As a mobile developer, I was sad to find nothing native that supports auto resizing. My searches did not turn up anything that worked for me and in the end, I spent the better half of my weekend and created my own auto resize text view. I will post the code here and hopefully it will be useful for someone else.

This class uses a static layout with the text paint of the original text view to measure the height. From there, I step down by 2 font pixels and remeasure until I have a size that fits. At the end, if the text still does not fit, I append an ellipsis. I had requirements to animate the text and reuse views and this seems to work well on the devices I have and seems to run fast enough for me.

/** * DO WHAT YOU WANT TO PUBLIC LICENSE * Version 2, December 2004 * * Copyright (C) 2004 Sam Hocevar <[email protected]> * * Everyone is permitted to copy and distribute verbatim or modified * copies of this license document, and changing it is allowed as long * as the name is changed. * * DO WHAT YOU WANT TO PUBLIC LICENSE * TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION * * 0. You just DO WHAT YOU WANT TO. */ import android.content.Context; import android.text.Layout.Alignment; import android.text.StaticLayout; import android.text.TextPaint; import android.util.AttributeSet; import android.util.TypedValue; import android.widget.TextView; /** * Text view that auto adjusts text size to fit within the view. * If the text size equals the minimum text size and still does not * fit, append with an ellipsis. * * @author Chase Colburn * @since Apr 4, 2011 */ public class AutoResizeTextView extends TextView { // Minimum text size for this text view public static final float MIN_TEXT_SIZE = 20; // Interface for resize notifications public interface OnTextResizeListener { public void onTextResize(TextView textView, float oldSize, float newSize); } // Our ellipse string private static final String mEllipsis = "..."; // Registered resize listener private OnTextResizeListener mTextResizeListener; // Flag for text and/or size changes to force a resize private boolean mNeedsResize = false; // Text size that is set from code. This acts as a starting point for resizing private float mTextSize; // Temporary upper bounds on the starting text size private float mMaxTextSize = 0; // Lower bounds for text size private float mMinTextSize = MIN_TEXT_SIZE; // Text view line spacing multiplier private float mSpacingMult = 1.0f; // Text view additional line spacing private float mSpacingAdd = 0.0f; // Add ellipsis to text that overflows at the smallest text size private boolean mAddEllipsis = true; // Default constructor override public AutoResizeTextView(Context context) { this(context, null); } // Default constructor when inflating from XML file public AutoResizeTextView(Context context, AttributeSet attrs) { this(context, attrs, 0); } // Default constructor override public AutoResizeTextView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); mTextSize = getTextSize(); } /** * When text changes, set the force resize flag to true and reset the text size. */ @Override protected void onTextChanged(final CharSequence text, final int start, final int before, final int after) { mNeedsResize = true; // Since this view may be reused, it is good to reset the text size resetTextSize(); } /** * If the text view size changed, set the force resize flag to true */ @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { if (w != oldw || h != oldh) { mNeedsResize = true; } } /** * Register listener to receive resize notifications * @param listener */ public void setOnResizeListener(OnTextResizeListener listener) { mTextResizeListener = listener; } /** * Override the set text size to update our internal reference values */ @Override public void setTextSize(float size) { super.setTextSize(size); mTextSize = getTextSize(); } /** * Override the set text size to update our internal reference values */ @Override public void setTextSize(int unit, float size) { super.setTextSize(unit, size); mTextSize = getTextSize(); } /** * Override the set line spacing to update our internal reference values */ @Override public void setLineSpacing(float add, float mult) { super.setLineSpacing(add, mult); mSpacingMult = mult; mSpacingAdd = add; } /** * Set the upper text size limit and invalidate the view * @param maxTextSize */ public void setMaxTextSize(float maxTextSize) { mMaxTextSize = maxTextSize; requestLayout(); invalidate(); } /** * Return upper text size limit * @return */ public float getMaxTextSize() { return mMaxTextSize; } /** * Set the lower text size limit and invalidate the view * @param minTextSize */ public void setMinTextSize(float minTextSize) { mMinTextSize = minTextSize; requestLayout(); invalidate(); } /** * Return lower text size limit * @return */ public float getMinTextSize() { return mMinTextSize; } /** * Set flag to add ellipsis to text that overflows at the smallest text size * @param addEllipsis */ public void setAddEllipsis(boolean addEllipsis) { mAddEllipsis = addEllipsis; } /** * Return flag to add ellipsis to text that overflows at the smallest text size * @return */ public boolean getAddEllipsis() { return mAddEllipsis; } /** * Reset the text to the original size */ public void resetTextSize() { if (mTextSize > 0) { super.setTextSize(TypedValue.COMPLEX_UNIT_PX, mTextSize); mMaxTextSize = mTextSize; } } /** * Resize text after measuring */ @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { if (changed || mNeedsResize) { int widthLimit = (right - left) - getCompoundPaddingLeft() - getCompoundPaddingRight(); int heightLimit = (bottom - top) - getCompoundPaddingBottom() - getCompoundPaddingTop(); resizeText(widthLimit, heightLimit); } super.onLayout(changed, left, top, right, bottom); } /** * Resize the text size with default width and height */ public void resizeText() { int heightLimit = getHeight() - getPaddingBottom() - getPaddingTop(); int widthLimit = getWidth() - getPaddingLeft() - getPaddingRight(); resizeText(widthLimit, heightLimit); } /** * Resize the text size with specified width and height * @param width * @param height */ public void resizeText(int width, int height) { CharSequence text = getText(); // Do not resize if the view does not have dimensions or there is no text if (text == null || text.length() == 0 || height <= 0 || width <= 0 || mTextSize == 0) { return; } if (getTransformationMethod() != null) { text = getTransformationMethod().getTransformation(text, this); } // Get the text view's paint object TextPaint textPaint = getPaint(); // Store the current text size float oldTextSize = textPaint.getTextSize(); // If there is a max text size set, use the lesser of that and the default text size float targetTextSize = mMaxTextSize > 0 ? Math.min(mTextSize, mMaxTextSize) : mTextSize; // Get the required text height int textHeight = getTextHeight(text, textPaint, width, targetTextSize); // Until we either fit within our text view or we had reached our min text size, incrementally try smaller sizes while (textHeight > height && targetTextSize > mMinTextSize) { targetTextSize = Math.max(targetTextSize - 2, mMinTextSize); textHeight = getTextHeight(text, textPaint, width, targetTextSize); } // If we had reached our minimum text size and still don't fit, append an ellipsis if (mAddEllipsis && targetTextSize == mMinTextSize && textHeight > height) { // Draw using a static layout // modified: use a copy of TextPaint for measuring TextPaint paint = new TextPaint(textPaint); // Draw using a static layout StaticLayout layout = new StaticLayout(text, paint, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, false); // Check that we have a least one line of rendered text if (layout.getLineCount() > 0) { // Since the line at the specific vertical position would be cut off, // we must trim up to the previous line int lastLine = layout.getLineForVertical(height) - 1; // If the text would not even fit on a single line, clear it if (lastLine < 0) { setText(""); } // Otherwise, trim to the previous line and add an ellipsis else { int start = layout.getLineStart(lastLine); int end = layout.getLineEnd(lastLine); float lineWidth = layout.getLineWidth(lastLine); float ellipseWidth = textPaint.measureText(mEllipsis); // Trim characters off until we have enough room to draw the ellipsis while (width < lineWidth + ellipseWidth) { lineWidth = textPaint.measureText(text.subSequence(start, --end + 1).toString()); } setText(text.subSequence(0, end) + mEllipsis); } } } // Some devices try to auto adjust line spacing, so force default line spacing // and invalidate the layout as a side effect setTextSize(TypedValue.COMPLEX_UNIT_PX, targetTextSize); setLineSpacing(mSpacingAdd, mSpacingMult); // Notify the listener if registered if (mTextResizeListener != null) { mTextResizeListener.onTextResize(this, oldTextSize, targetTextSize); } // Reset force resize flag mNeedsResize = false; } // Set the text size of the text paint object and use a static layout to render text off screen before measuring private int getTextHeight(CharSequence source, TextPaint paint, int width, float textSize) { // modified: make a copy of the original TextPaint object for measuring // (apparently the object gets modified while measuring, see also the // docs for TextView.getPaint() (which states to access it read-only) TextPaint paintCopy = new TextPaint(paint); // Update the text paint object paintCopy.setTextSize(textSize); // Measure using a static layout StaticLayout layout = new StaticLayout(source, paintCopy, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true); return layout.getHeight(); } } 

Warning. There is an important fixed bug affecting Android 3.1 - 4.04 causing all AutoResizingTextView widgets not to work. Please read: https://stackoverflow.com/a/21851157/2075875

UPDATE: Following code also fulfills the requirement of an ideal AutoScaleTextView as described here : Auto-fit TextView for Android and is marked as winner.

UPDATE 2: Support of maxlines added, now works fine before API level 16.

Update 3: Support for android:drawableLeft, android:drawableRight, android:drawableTop and android:drawableBottom tags added, thanks to MartinH's simple fix here.

My requirements were little bit different. I needed an efficient way to adjust size because I was animating an integer from, may be 0 to ~4000 in TextView in 2 seconds and I wanted to adjust the size accordingly. My solution works bit differently. Here is what final result looks like:

and the code that produced it:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="vertical" android:padding="16dp" > <com.vj.widgets.AutoResizeTextView android:layout_width="match_parent" android:layout_height="100dp" android:ellipsize="none" android:maxLines="2" android:text="Auto Resized Text, max 2 lines" android:textSize="100sp" /> <!-- maximum size --> <com.vj.widgets.AutoResizeTextView android:layout_width="match_parent" android:layout_height="100dp" android:ellipsize="none" android:gravity="center" android:maxLines="1" android:text="Auto Resized Text, max 1 line" android:textSize="100sp" /> <!-- maximum size --> <com.vj.widgets.AutoResizeTextView android:layout_width="match_parent" android:layout_height="wrap_content" android:text="Auto Resized Text" android:textSize="500sp" /> <!-- maximum size --> </LinearLayout> 

And finally the java code:

import android.annotation.TargetApi; import android.content.Context; import android.content.res.Resources; import android.graphics.RectF; import android.os.Build; import android.text.Layout.Alignment; import android.text.StaticLayout; import android.text.TextPaint; import android.util.AttributeSet; import android.util.SparseIntArray; import android.util.TypedValue; import android.widget.TextView; public class AutoResizeTextView extends TextView { private interface SizeTester { /** * * @param suggestedSize * Size of text to be tested * @param availableSpace * available space in which text must fit * @return an integer < 0 if after applying {@code suggestedSize} to * text, it takes less space than {@code availableSpace}, > 0 * otherwise */ public int onTestSize(int suggestedSize, RectF availableSpace); } private RectF mTextRect = new RectF(); private RectF mAvailableSpaceRect; private SparseIntArray mTextCachedSizes; private TextPaint mPaint; private float mMaxTextSize; private float mSpacingMult = 1.0f; private float mSpacingAdd = 0.0f; private float mMinTextSize = 20; private int mWidthLimit; private static final int NO_LINE_LIMIT = -1; private int mMaxLines; private boolean mEnableSizeCache = true; private boolean mInitiallized; public AutoResizeTextView(Context context) { super(context); initialize(); } public AutoResizeTextView(Context context, AttributeSet attrs) { super(context, attrs); initialize(); } public AutoResizeTextView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); initialize(); } private void initialize() { mPaint = new TextPaint(getPaint()); mMaxTextSize = getTextSize(); mAvailableSpaceRect = new RectF(); mTextCachedSizes = new SparseIntArray(); if (mMaxLines == 0) { // no value was assigned during construction mMaxLines = NO_LINE_LIMIT; } mInitiallized = true; } @Override public void setText(final CharSequence text, BufferType type) { super.setText(text, type); adjustTextSize(text.toString()); } @Override public void setTextSize(float size) { mMaxTextSize = size; mTextCachedSizes.clear(); adjustTextSize(getText().toString()); } @Override public void setMaxLines(int maxlines) { super.setMaxLines(maxlines); mMaxLines = maxlines; reAdjust(); } public int getMaxLines() { return mMaxLines; } @Override public void setSingleLine() { super.setSingleLine(); mMaxLines = 1; reAdjust(); } @Override public void setSingleLine(boolean singleLine) { super.setSingleLine(singleLine); if (singleLine) { mMaxLines = 1; } else { mMaxLines = NO_LINE_LIMIT; } reAdjust(); } @Override public void setLines(int lines) { super.setLines(lines); mMaxLines = lines; reAdjust(); } @Override public void setTextSize(int unit, float size) { Context c = getContext(); Resources r; if (c == null) r = Resources.getSystem(); else r = c.getResources(); mMaxTextSize = TypedValue.applyDimension(unit, size, r.getDisplayMetrics()); mTextCachedSizes.clear(); adjustTextSize(getText().toString()); } @Override public void setLineSpacing(float add, float mult) { super.setLineSpacing(add, mult); mSpacingMult = mult; mSpacingAdd = add; } /** * Set the lower text size limit and invalidate the view * * @param minTextSize */ public void setMinTextSize(float minTextSize) { mMinTextSize = minTextSize; reAdjust(); } private void reAdjust() { adjustTextSize(getText().toString()); } private void adjustTextSize(String string) { if (!mInitiallized) { return; } int startSize = (int) mMinTextSize; int heightLimit = getMeasuredHeight() - getCompoundPaddingBottom() - getCompoundPaddingTop(); mWidthLimit = getMeasuredWidth() - getCompoundPaddingLeft() - getCompoundPaddingRight(); mAvailableSpaceRect.right = mWidthLimit; mAvailableSpaceRect.bottom = heightLimit; super.setTextSize( TypedValue.COMPLEX_UNIT_PX, efficientTextSizeSearch(startSize, (int) mMaxTextSize, mSizeTester, mAvailableSpaceRect)); } private final SizeTester mSizeTester = new SizeTester() { @TargetApi(Build.VERSION_CODES.JELLY_BEAN) @Override public int onTestSize(int suggestedSize, RectF availableSPace) { mPaint.setTextSize(suggestedSize); String text = getText().toString(); boolean singleline = getMaxLines() == 1; if (singleline) { mTextRect.bottom = mPaint.getFontSpacing(); mTextRect.right = mPaint.measureText(text); } else { StaticLayout layout = new StaticLayout(text, mPaint, mWidthLimit, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true); // return early if we have more lines if (getMaxLines() != NO_LINE_LIMIT && layout.getLineCount() > getMaxLines()) { return 1; } mTextRect.bottom = layout.getHeight(); int maxWidth = -1; for (int i = 0; i < layout.getLineCount(); i++) { if (maxWidth < layout.getLineWidth(i)) { maxWidth = (int) layout.getLineWidth(i); } } mTextRect.right = maxWidth; } mTextRect.offsetTo(0, 0); if (availableSPace.contains(mTextRect)) { // may be too small, don't worry we will find the best match return -1; } else { // too big return 1; } } }; /** * Enables or disables size caching, enabling it will improve performance * where you are animating a value inside TextView. This stores the font * size against getText().length() Be careful though while enabling it as 0 * takes more space than 1 on some fonts and so on. * * @param enable * enable font size caching */ public void enableSizeCache(boolean enable) { mEnableSizeCache = enable; mTextCachedSizes.clear(); adjustTextSize(getText().toString()); } private int efficientTextSizeSearch(int start, int end, SizeTester sizeTester, RectF availableSpace) { if (!mEnableSizeCache) { return binarySearch(start, end, sizeTester, availableSpace); } String text = getText().toString(); int key = text == null ? 0 : text.length(); int size = mTextCachedSizes.get(key); if (size != 0) { return size; } size = binarySearch(start, end, sizeTester, availableSpace); mTextCachedSizes.put(key, size); return size; } private static int binarySearch(int start, int end, SizeTester sizeTester, RectF availableSpace) { int lastBest = start; int lo = start; int hi = end - 1; int mid = 0; while (lo <= hi) { mid = (lo + hi) >>> 1; int midValCmp = sizeTester.onTestSize(mid, availableSpace); if (midValCmp < 0) { lastBest = lo; lo = mid + 1; } else if (midValCmp > 0) { hi = mid - 1; lastBest = hi; } else { return mid; } } // make sure to return last best // this is what should always be returned return lastBest; } @Override protected void onTextChanged(final CharSequence text, final int start, final int before, final int after) { super.onTextChanged(text, start, before, after); reAdjust(); } @Override protected void onSizeChanged(int width, int height, int oldwidth, int oldheight) { mTextCachedSizes.clear(); super.onSizeChanged(width, height, oldwidth, oldheight); if (width != oldwidth || height != oldheight) { reAdjust(); } } } 

Actually a solution is in Google's DialogTitle class... though it's not as effective as the accepted one, it's a lot simpler and is easy to adapt.

public class SingleLineTextView extends TextView { public SingleLineTextView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); setSingleLine(); setEllipsize(TruncateAt.END); } public SingleLineTextView(Context context, AttributeSet attrs) { super(context, attrs); setSingleLine(); setEllipsize(TruncateAt.END); } public SingleLineTextView(Context context) { super(context); setSingleLine(); setEllipsize(TruncateAt.END); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); final Layout layout = getLayout(); if (layout != null) { final int lineCount = layout.getLineCount(); if (lineCount > 0) { final int ellipsisCount = layout.getEllipsisCount(lineCount - 1); if (ellipsisCount > 0) { final float textSize = getTextSize(); // textSize is already expressed in pixels setTextSize(TypedValue.COMPLEX_UNIT_PX, (textSize - 1)); super.onMeasure(widthMeasureSpec, heightMeasureSpec); } } } } } 

I started with Chase's solution, but had to adapt two things before it was working as expected on my device (Galaxy Nexus, Android 4.1):

1. using a copy of TextPaint for measuring layout The documentation for TextView.getPaint() states that it should be used read-only, so I made a copy in both places where we use the paint object for measuring:

   // 1. in resizeText() if (mAddEllipsis && targetTextSize == mMinTextSize && textHeight > height) { // Draw using a static layout // modified: use a copy of TextPaint for measuring TextPaint paint = new TextPaint(textPaint); // 2. in getTextHeight() private int getTextHeight(CharSequence source, TextPaint originalPaint, int width, float textSize) { // modified: make a copy of the original TextPaint object for measuring // (apparently the object gets modified while measuring, see also the // docs for TextView.getPaint() (which states to access it read-only) TextPaint paint = new TextPaint(originalPaint); // Update the text paint object paint.setTextSize(textSize); ... 

2. adding a unit to setting the text size

   // modified: setting text size via this.setTextSize (instead of textPaint.setTextSize(targetTextSize)) setTextSize(TypedValue.COMPLEX_UNIT_PX, targetTextSize); setLineSpacing(mSpacingAdd, mSpacingMult); 

With these two modifications the solution is working perfectly for me, thanks Chase! I don't know whether it is due to Android 4.x that the original solution was not working. In case you want to see it in action or test whether it really works on your device, you can have a look at my flashcard app Flashcards ToGo where I use this solution to scale the text of a flashcard. The text can have arbitrary length, and the flashcards are displayed in different activities, sometimes smaller sometimes bigger, plus in landscape + portrait mode, and I haven't found any corner case where the solution would not work properly...

AppcompatTextView now supports auto sizing starting from Support Library 26.0. TextView in Android O also works same way. More info can be found here. A simple demo app can be found here.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="wrap_content"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" app:autoSizeTextType="uniform" app:autoSizeMinTextSize="12sp" app:autoSizeMaxTextSize="100sp" app:autoSizeStepGranularity="2sp" /> </LinearLayout> 

Text to Fit Bounds (1 line)

To have the text shrink to fit bounds for one line:

<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" app:autoSizeTextType="uniform" android:lines="1"/> 

I started with Chase's AutoResizeTextView class, and made a minor change so it would fit both vertically and horizontally.

I also discovered a bug which causes a Null Pointer Exception in the Layout Editor (in Eclipse) under some rather obscure conditions.

Change 1: Fit the text both vertically and horizontally

Chase's original version reduces the text size until it fits vertically, but allows the text to be wider than the target. In my case, I needed the text to fit a specified width.

This change makes it resize until the text fits both vertically and horizontally.

In resizeText(int,int) change from:

// Get the required text height int textHeight = getTextHeight(text, textPaint, width, targetTextSize); // Until we either fit within our text view or we had reached our min text size, incrementally try smaller sizes while(textHeight > height && targetTextSize > mMinTextSize) { targetTextSize = Math.max(targetTextSize - 2, mMinTextSize); textHeight = getTextHeight(text, textPaint, width, targetTextSize); } 

to:

// Get the required text height int textHeight = getTextHeight(text, textPaint, width, targetTextSize); int textWidth = getTextWidth(text, textPaint, width, targetTextSize); // Until we either fit within our text view or we had reached our min text size, incrementally try smaller sizes while(((textHeight >= height) || (textWidth >= width) ) && targetTextSize > mMinTextSize) { targetTextSize = Math.max(targetTextSize - 2, mMinTextSize); textHeight = getTextHeight(text, textPaint, width, targetTextSize); textWidth = getTextWidth(text, textPaint, width, targetTextSize); } 

Then, at the end of the file, append the getTextWidth() routine; it's just a slightly modified getTextHeight(). It probably would be more efficient to combine them to one routine which returns both height and width.

// Set the text size of the text paint object and use a static layout to render text off screen before measuring private int getTextWidth(CharSequence source, TextPaint paint, int width, float textSize) { // Update the text paint object paint.setTextSize(textSize); // Draw using a static layout StaticLayout layout = new StaticLayout(source, paint, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true); layout.draw(sTextResizeCanvas); return layout.getWidth(); } 

Change 2: Fix a EmptyStackException in the Eclipse Android Layout Editor

Under rather obscure and very precise conditions, the Layout Editor will fail to display the graphical display of the layout; it will throw an "EmptyStackException: null" exception in com.android.ide.eclipse.adt.

The conditions required are:
- create an AutoResizeTextView widget
- create a style for that widget
- specify the text item in the style; not in the widget definition

as in:

res/layout/main.xml:

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <com.ajw.DemoCrashInADT.AutoResizeTextView android:id="@+id/resizingText" style="@style/myTextStyle" /> </LinearLayout> 

res/values/myStyles.xml:

<?xml version="1.0" encoding="utf-8"?> <resources> <style name="myTextStyle" parent="@android:style/Widget.TextView"> <item name="android:layout_height">wrap_content</item> <item name="android:layout_width">fill_parent</item> <item name="android:text">some message</item> </style> </resources> 

With these files, selecting the Graphical Layout tab when editing main.xml will display:

error!
EmptyStackException: null
Exception details are logged in Window > Show View > Error Log

instead of the graphical view of the layout.

To keep an already too-long story shorter, I tracked this down to the following lines (again in resizeText):

// If there is a max text size set, use the lesser of that and the default text size float targetTextSize = mMaxTextSize > 0 ? Math.min(mTextSize, mMaxTextSize) : mTextSize; 

The problem is that under the specific conditions, mTextSize is never initialized; it has the value 0.

With the above, targetTextSize is set to zero (as a result of Math.min).

That zero is passed to getTextHeight() (and getTextWidth()) as the textSize argument. When it gets to
layout.draw(sTextResizeCanvas);
we get the exception.

It's more efficient to test if (mTextSize == 0) at the beginning of resizeText() rather than testing in getTextHeight() and getTextWidth(); testing earlier saves all the intervening work.

With these updates, the file (as in my crash-demo test app) is now:

// // from: http://stackoverflow.com/questions/5033012/auto-scale-textview-text-to-fit-within-bounds // // package com.ajw.DemoCrashInADT; import android.content.Context; import android.graphics.Canvas; import android.text.Layout.Alignment; import android.text.StaticLayout; import android.text.TextPaint; import android.util.AttributeSet; import android.util.TypedValue; import android.widget.TextView; /** * Text view that auto adjusts text size to fit within the view. If the text * size equals the minimum text size and still does not fit, append with an * ellipsis. * * 2011-10-29 changes by Alan Jay Weiner * * change to fit both vertically and horizontally * * test mTextSize for 0 in resizeText() to fix exception in Layout Editor * * @author Chase Colburn * @since Apr 4, 2011 */ public class AutoResizeTextView extends TextView { // Minimum text size for this text view public static final float MIN_TEXT_SIZE = 20; // Interface for resize notifications public interface OnTextResizeListener { public void onTextResize(TextView textView, float oldSize, float newSize); } // Off screen canvas for text size rendering private static final Canvas sTextResizeCanvas = new Canvas(); // Our ellipse string private static final String mEllipsis = "..."; // Registered resize listener private OnTextResizeListener mTextResizeListener; // Flag for text and/or size changes to force a resize private boolean mNeedsResize = false; // Text size that is set from code. This acts as a starting point for // resizing private float mTextSize; // Temporary upper bounds on the starting text size private float mMaxTextSize = 0; // Lower bounds for text size private float mMinTextSize = MIN_TEXT_SIZE; // Text view line spacing multiplier private float mSpacingMult = 1.0f; // Text view additional line spacing private float mSpacingAdd = 0.0f; // Add ellipsis to text that overflows at the smallest text size private boolean mAddEllipsis = true; // Default constructor override public AutoResizeTextView(Context context) { this(context, null); } // Default constructor when inflating from XML file public AutoResizeTextView(Context context, AttributeSet attrs) { this(context, attrs, 0); } // Default constructor override public AutoResizeTextView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); mTextSize = getTextSize(); } /** * When text changes, set the force resize flag to true and reset the text * size. */ @Override protected void onTextChanged(final CharSequence text, final int start, final int before, final int after) { mNeedsResize = true; // Since this view may be reused, it is good to reset the text size resetTextSize(); } /** * If the text view size changed, set the force resize flag to true */ @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { if (w != oldw || h != oldh) { mNeedsResize = true; } } /** * Register listener to receive resize notifications * * @param listener */ public void setOnResizeListener(OnTextResizeListener listener) { mTextResizeListener = listener; } /** * Override the set text size to update our internal reference values */ @Override public void setTextSize(float size) { super.setTextSize(size); mTextSize = getTextSize(); } /** * Override the set text size to update our internal reference values */ @Override public void setTextSize(int unit, float size) { super.setTextSize(unit, size); mTextSize = getTextSize(); } /** * Override the set line spacing to update our internal reference values */ @Override public void setLineSpacing(float add, float mult) { super.setLineSpacing(add, mult); mSpacingMult = mult; mSpacingAdd = add; } /** * Set the upper text size limit and invalidate the view * * @param maxTextSize */ public void setMaxTextSize(float maxTextSize) { mMaxTextSize = maxTextSize; requestLayout(); invalidate(); } /** * Return upper text size limit * * @return */ public float getMaxTextSize() { return mMaxTextSize; } /** * Set the lower text size limit and invalidate the view * * @param minTextSize */ public void setMinTextSize(float minTextSize) { mMinTextSize = minTextSize; requestLayout(); invalidate(); } /** * Return lower text size limit * * @return */ public float getMinTextSize() { return mMinTextSize; } /** * Set flag to add ellipsis to text that overflows at the smallest text size * * @param addEllipsis */ public void setAddEllipsis(boolean addEllipsis) { mAddEllipsis = addEllipsis; } /** * Return flag to add ellipsis to text that overflows at the smallest text * size * * @return */ public boolean getAddEllipsis() { return mAddEllipsis; } /** * Reset the text to the original size */ public void resetTextSize() { super.setTextSize(TypedValue.COMPLEX_UNIT_PX, mTextSize); mMaxTextSize = mTextSize; } /** * Resize text after measuring */ @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { if (changed || mNeedsResize) { int widthLimit = (right - left) - getCompoundPaddingLeft() - getCompoundPaddingRight(); int heightLimit = (bottom - top) - getCompoundPaddingBottom() - getCompoundPaddingTop(); resizeText(widthLimit, heightLimit); } super.onLayout(changed, left, top, right, bottom); } /** * Resize the text size with default width and height */ public void resizeText() { int heightLimit = getHeight() - getPaddingBottom() - getPaddingTop(); int widthLimit = getWidth() - getPaddingLeft() - getPaddingRight(); resizeText(widthLimit, heightLimit); } /** * Resize the text size with specified width and height * * @param width * @param height */ public void resizeText(int width, int height) { CharSequence text = getText(); // Do not resize if the view does not have dimensions or there is no // text // or if mTextSize has not been initialized if (text == null || text.length() == 0 || height <= 0 || width <= 0 || mTextSize == 0) { return; } // Get the text view's paint object TextPaint textPaint = getPaint(); // Store the current text size float oldTextSize = textPaint.getTextSize(); // If there is a max text size set, use the lesser of that and the // default text size float targetTextSize = mMaxTextSize > 0 ? Math.min(mTextSize, mMaxTextSize) : mTextSize; // Get the required text height int textHeight = getTextHeight(text, textPaint, width, targetTextSize); int textWidth = getTextWidth(text, textPaint, width, targetTextSize); // Until we either fit within our text view or we had reached our min // text size, incrementally try smaller sizes while (((textHeight > height) || (textWidth > width)) && targetTextSize > mMinTextSize) { targetTextSize = Math.max(targetTextSize - 2, mMinTextSize); textHeight = getTextHeight(text, textPaint, width, targetTextSize); textWidth = getTextWidth(text, textPaint, width, targetTextSize); } // If we had reached our minimum text size and still don't fit, append // an ellipsis if (mAddEllipsis && targetTextSize == mMinTextSize && textHeight > height) { // Draw using a static layout StaticLayout layout = new StaticLayout(text, textPaint, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, false); layout.draw(sTextResizeCanvas); int lastLine = layout.getLineForVertical(height) - 1; int start = layout.getLineStart(lastLine); int end = layout.getLineEnd(lastLine); float lineWidth = layout.getLineWidth(lastLine); float ellipseWidth = textPaint.measureText(mEllipsis); // Trim characters off until we have enough room to draw the // ellipsis while (width < lineWidth + ellipseWidth) { lineWidth = textPaint.measureText(text.subSequence(start, --end + 1) .toString()); } setText(text.subSequence(0, end) + mEllipsis); } // Some devices try to auto adjust line spacing, so force default line // spacing // and invalidate the layout as a side effect textPaint.setTextSize(targetTextSize); setLineSpacing(mSpacingAdd, mSpacingMult); // Notify the listener if registered if (mTextResizeListener != null) { mTextResizeListener.onTextResize(this, oldTextSize, targetTextSize); } // Reset force resize flag mNeedsResize = false; } // Set the text size of the text paint object and use a static layout to // render text off screen before measuring private int getTextHeight(CharSequence source, TextPaint paint, int width, float textSize) { // Update the text paint object paint.setTextSize(textSize); // Draw using a static layout StaticLayout layout = new StaticLayout(source, paint, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true); layout.draw(sTextResizeCanvas); return layout.getHeight(); } // Set the text size of the text paint object and use a static layout to // render text off screen before measuring private int getTextWidth(CharSequence source, TextPaint paint, int width, float textSize) { // Update the text paint object paint.setTextSize(textSize); // Draw using a static layout StaticLayout layout = new StaticLayout(source, paint, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true); layout.draw(sTextResizeCanvas); return layout.getWidth(); } } 

A big thank you to Chase for posting the initial code. I enjoyed reading through it to see how it worked, and I'm pleased to be able to add to it.

At google IO conference in 2017, google introduced autoSize property of TextView

https://youtu.be/fjUdJ2aVqE4

<android.support.v7.widget.AppCompatTextView android:layout_width="match_parent" android:layout_height="match_parent" android:text="@string/my_text" app:autoSizeTextType="uniform" app:autoSizeMaxTextSize="10sp" app:autoSizeMinTextSize="6sp" app:autoSizeStepGranularity="1sp"/> 

A workaround for Android 4.x:

I found AutoResizeTextView and it works great on my Android 2.1 emulator. I loved it so much. But unfortunately it failed on my own 4.0.4 cellphone and 4.1 emulator. After trying I found it could be easily resolved by adding following attributes in AutoResizeTextView class in the xml:

android:ellipsize="none"

android:singleLine="true"

With the 2 lines above, now AutoResizeTextView working perfectly on my 2.1 & 4.1 emulators and my own 4.0.4 cellphone now.

Hope this helps you. :-)

Warning, bug in Android Honeycomb and Ice Cream Sandwich

Androids versions: 3.1 - 4.04 have a bug, that setTextSize() inside of TextView works only for the 1st time (1st invocation).

Bug is described here: http://code.google.com/p/android/issues/detail?id=22493 http://code.google.com/p/android/issues/detail?id=17343#c9

workaround is to add new line character to text assigned to TextView before changing size:

final String DOUBLE_BYTE_SPACE = "\u3000"; textView.append(DOUBLE_BYTE_SPACE); 

I use it in my code as follow:

final String DOUBLE_BYTE_SPACE = "\u3000"; AutoResizeTextView textView = (AutoResizeTextView) view.findViewById(R.id.aTextView); String fixString = ""; if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.HONEYCOMB_MR1 && android.os.Build.VERSION.SDK_INT <= android.os.Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1) { fixString = DOUBLE_BYTE_SPACE; } textView.setText(fixString + "The text" + fixString); 

I add this "\u3000" character on left and right of my text, to keep it centered. If you have it aligned to left then append to the right only. Of course it can be also embedded with AutoResizeTextView widget, but I wanted to keep fix code outside.

My need was to resize text in order to perfectly fit view bounds. Chase's solution only reduces text size, this one enlarges also the text if there is enough space.

To make all fast & precise i used a bisection method instead of an iterative while, as you can see in resizeText() method. That's why you have also a MAX_TEXT_SIZE option. I also included onoelle's tips.

Tested on Android 4.4

/** * DO WHAT YOU WANT TO PUBLIC LICENSE * Version 2, December 2004 * * Copyright (C) 2004 Sam Hocevar <[email protected]> * * Everyone is permitted to copy and distribute verbatim or modified * copies of this license document, and changing it is allowed as long * as the name is changed. * * DO WHAT YOU WANT TO PUBLIC LICENSE * TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION * * 0. You just DO WHAT YOU WANT TO. */ import android.content.Context; import android.text.Layout.Alignment; import android.text.StaticLayout; import android.text.TextPaint; import android.util.AttributeSet; import android.util.TypedValue; import android.widget.TextView; /** * Text view that auto adjusts text size to fit within the view. * If the text size equals the minimum text size and still does not * fit, append with an ellipsis. * * @author Chase Colburn * @since Apr 4, 2011 */ public class AutoResizeTextView extends TextView { // Minimum text size for this text view public static final float MIN_TEXT_SIZE = 26; // Maximum text size for this text view public static final float MAX_TEXT_SIZE = 128; private static final int BISECTION_LOOP_WATCH_DOG = 30; // Interface for resize notifications public interface OnTextResizeListener { public void onTextResize(TextView textView, float oldSize, float newSize); } // Our ellipse string private static final String mEllipsis = "..."; // Registered resize listener private OnTextResizeListener mTextResizeListener; // Flag for text and/or size changes to force a resize private boolean mNeedsResize = false; // Text size that is set from code. This acts as a starting point for resizing private float mTextSize; // Temporary upper bounds on the starting text size private float mMaxTextSize = MAX_TEXT_SIZE; // Lower bounds for text size private float mMinTextSize = MIN_TEXT_SIZE; // Text view line spacing multiplier private float mSpacingMult = 1.0f; // Text view additional line spacing private float mSpacingAdd = 0.0f; // Add ellipsis to text that overflows at the smallest text size private boolean mAddEllipsis = true; // Default constructor override public AutoResizeTextView(Context context) { this(context, null); } // Default constructor when inflating from XML file public AutoResizeTextView(Context context, AttributeSet attrs) { this(context, attrs, 0); } // Default constructor override public AutoResizeTextView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); mTextSize = getTextSize(); } /** * When text changes, set the force resize flag to true and reset the text size. */ @Override protected void onTextChanged(final CharSequence text, final int start, final int before, final int after) { mNeedsResize = true; // Since this view may be reused, it is good to reset the text size resetTextSize(); } /** * If the text view size changed, set the force resize flag to true */ @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { if (w != oldw || h != oldh) { mNeedsResize = true; } } /** * Register listener to receive resize notifications * @param listener */ public void setOnResizeListener(OnTextResizeListener listener) { mTextResizeListener = listener; } /** * Override the set text size to update our internal reference values */ @Override public void setTextSize(float size) { super.setTextSize(size); mTextSize = getTextSize(); } /** * Override the set text size to update our internal reference values */ @Override public void setTextSize(int unit, float size) { super.setTextSize(unit, size); mTextSize = getTextSize(); } /** * Override the set line spacing to update our internal reference values */ @Override public void setLineSpacing(float add, float mult) { super.setLineSpacing(add, mult); mSpacingMult = mult; mSpacingAdd = add; } /** * Set the upper text size limit and invalidate the view * @param maxTextSize */ public void setMaxTextSize(float maxTextSize) { mMaxTextSize = maxTextSize; requestLayout(); invalidate(); } /** * Return upper text size limit * @return */ public float getMaxTextSize() { return mMaxTextSize; } /** * Set the lower text size limit and invalidate the view * @param minTextSize */ public void setMinTextSize(float minTextSize) { mMinTextSize = minTextSize; requestLayout(); invalidate(); } /** * Return lower text size limit * @return */ public float getMinTextSize() { return mMinTextSize; } /** * Set flag to add ellipsis to text that overflows at the smallest text size * @param addEllipsis */ public void setAddEllipsis(boolean addEllipsis) { mAddEllipsis = addEllipsis; } /** * Return flag to add ellipsis to text that overflows at the smallest text size * @return */ public boolean getAddEllipsis() { return mAddEllipsis; } /** * Reset the text to the original size */ public void resetTextSize() { if(mTextSize > 0) { super.setTextSize(TypedValue.COMPLEX_UNIT_PX, mTextSize); //mMaxTextSize = mTextSize; } } /** * Resize text after measuring */ @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { if(changed || mNeedsResize) { int widthLimit = (right - left) - getCompoundPaddingLeft() - getCompoundPaddingRight(); int heightLimit = (bottom - top) - getCompoundPaddingBottom() - getCompoundPaddingTop(); resizeText(widthLimit, heightLimit); } super.onLayout(changed, left, top, right, bottom); } /** * Resize the text size with default width and height */ public void resizeText() { int heightLimit = getHeight() - getPaddingBottom() - getPaddingTop(); int widthLimit = getWidth() - getPaddingLeft() - getPaddingRight(); resizeText(widthLimit, heightLimit); } /** * Resize the text size with specified width and height * @param width * @param height */ public void resizeText(int width, int height) { CharSequence text = getText(); // Do not resize if the view does not have dimensions or there is no text if(text == null || text.length() == 0 || height <= 0 || width <= 0 || mTextSize == 0) { return; } // Get the text view's paint object TextPaint textPaint = getPaint(); // Store the current text size float oldTextSize = textPaint.getTextSize(); // Bisection method: fast & precise float lower = mMinTextSize; float upper = mMaxTextSize; int loop_counter=1; float targetTextSize = (lower+upper)/2; int textHeight = getTextHeight(text, textPaint, width, targetTextSize); while(loop_counter < BISECTION_LOOP_WATCH_DOG && upper - lower > 1) { targetTextSize = (lower+upper)/2; textHeight = getTextHeight(text, textPaint, width, targetTextSize); if(textHeight > height) upper = targetTextSize; else lower = targetTextSize; loop_counter++; } targetTextSize = lower; textHeight = getTextHeight(text, textPaint, width, targetTextSize); // If we had reached our minimum text size and still don't fit, append an ellipsis if(mAddEllipsis && targetTextSize == mMinTextSize && textHeight > height) { // Draw using a static layout // modified: use a copy of TextPaint for measuring TextPaint paintCopy = new TextPaint(textPaint); paintCopy.setTextSize(targetTextSize); StaticLayout layout = new StaticLayout(text, paintCopy, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, false); // Check that we have a least one line of rendered text if(layout.getLineCount() > 0) { // Since the line at the specific vertical position would be cut off, // we must trim up to the previous line int lastLine = layout.getLineForVertical(height) - 1; // If the text would not even fit on a single line, clear it if(lastLine < 0) { setText(""); } // Otherwise, trim to the previous line and add an ellipsis else { int start = layout.getLineStart(lastLine); int end = layout.getLineEnd(lastLine); float lineWidth = layout.getLineWidth(lastLine); float ellipseWidth = paintCopy.measureText(mEllipsis); // Trim characters off until we have enough room to draw the ellipsis while(width < lineWidth + ellipseWidth) { lineWidth = paintCopy.measureText(text.subSequence(start, --end + 1).toString()); } setText(text.subSequence(0, end) + mEllipsis); } } } // Some devices try to auto adjust line spacing, so force default line spacing // and invalidate the layout as a side effect setTextSize(TypedValue.COMPLEX_UNIT_PX, targetTextSize); setLineSpacing(mSpacingAdd, mSpacingMult); // Notify the listener if registered if(mTextResizeListener != null) { mTextResizeListener.onTextResize(this, oldTextSize, targetTextSize); } // Reset force resize flag mNeedsResize = false; } // Set the text size of the text paint object and use a static layout to render text off screen before measuring private int getTextHeight(CharSequence source, TextPaint originalPaint, int width, float textSize) { // modified: make a copy of the original TextPaint object for measuring // (apparently the object gets modified while measuring, see also the // docs for TextView.getPaint() (which states to access it read-only) TextPaint paint = new TextPaint(originalPaint); // Update the text paint object paint.setTextSize(textSize); // Measure using a static layout StaticLayout layout = new StaticLayout(source, paint, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true); return layout.getHeight(); } } 

Since I've been looking for this forever, and I found a solution a while ago which is missing here, I'm gonna write it here, for future reference also.

Note: this code was taken directly from Google Android Lollipop dialer a while back, I don't remember If changes were made at the time. Also, I don't know which license is this under, but I have reason to think it is Apache 2.0.

Class ResizeTextView, the actual View

public class ResizeTextView extends TextView { private final int mOriginalTextSize; private final int mMinTextSize; private final static int sMinSize = 20; public ResizeTextView(Context context, AttributeSet attrs) { super(context, attrs); mOriginalTextSize = (int) getTextSize(); mMinTextSize = (int) sMinSize; } @Override protected void onTextChanged(CharSequence text, int start, int lengthBefore, int lengthAfter) { super.onTextChanged(text, start, lengthBefore, lengthAfter); ViewUtil.resizeText(this, mOriginalTextSize, mMinTextSize); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { super.onSizeChanged(w, h, oldw, oldh); ViewUtil.resizeText(this, mOriginalTextSize, mMinTextSize); } 

This ResizeTextView class could extend TextView and all its children as I undestand, so EditText as well.

Class ViewUtil with method resizeText(...)

/* * Copyright (C) 2012 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import android.graphics.Paint; import android.util.TypedValue; import android.widget.TextView; public class ViewUtil { private ViewUtil() {} public static void resizeText(TextView textView, int originalTextSize, int minTextSize) { final Paint paint = textView.getPaint(); final int width = textView.getWidth(); if (width == 0) return; textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, originalTextSize); float ratio = width / paint.measureText(textView.getText().toString()); if (ratio <= 1.0f) { textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, Math.max(minTextSize, originalTextSize * ratio)); } } } 

You should set your view as

<yourpackage.yourapp.ResizeTextView android:layout_width="match_parent" android:layout_height="64dp" android:gravity="center" android:maxLines="1"/> 

Hope it helps!

I hope this helps you

import android.content.Context; import android.graphics.Rect; import android.text.TextPaint; import android.util.AttributeSet; import android.widget.TextView; /* Based on * from http://stackoverflow.com/questions/2617266/how-to-adjust-text-font-size-to-fit-textview */ public class FontFitTextView extends TextView { private static float MAX_TEXT_SIZE = 20; public FontFitTextView(Context context) { this(context, null); } public FontFitTextView(Context context, AttributeSet attrs) { super(context, attrs); float size = this.getTextSize(); if (size > MAX_TEXT_SIZE) setTextSize(MAX_TEXT_SIZE); } private void refitText(String text, int textWidth) { if (textWidth > 0) { float availableWidth = textWidth - this.getPaddingLeft() - this.getPaddingRight(); TextPaint tp = getPaint(); Rect rect = new Rect(); tp.getTextBounds(text, 0, text.length(), rect); float size = rect.width(); if (size > availableWidth) setTextScaleX(availableWidth / size); } } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); int parentWidth = MeasureSpec.getSize(widthMeasureSpec); int parentHeight = MeasureSpec.getSize(heightMeasureSpec); refitText(this.getText().toString(), parentWidth); this.setMeasuredDimension(parentWidth, parentHeight); } @Override protected void onTextChanged(final CharSequence text, final int start, final int before, final int after) { refitText(text.toString(), this.getWidth()); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { if (w != oldw) { refitText(this.getText().toString(), w); } } } 

NOTE: I use MAX_TEXT_SIZE in case of text size is bigger than 20 because I don't want to allow big fonts applies to my View, if this is not your case, you can just simply remove it.

Here's a simple solution that uses TextView itself with a TextChangedListened added to it:

expressionView = (TextView) findViewById(R.id.expressionView); expressionView.addTextChangedListener(textAutoResizeWatcher(expressionView, 25, 55)); private TextWatcher textAutoResizeWatcher(final TextView view, final int MIN_SP, final int MAX_SP) { return new TextWatcher() { @Override public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {} @Override public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {} @Override public void afterTextChanged(Editable editable) { final int widthLimitPixels = view.getWidth() - view.getPaddingRight() - view.getPaddingLeft(); Paint paint = new Paint(); float fontSizeSP = pixelsToSp(view.getTextSize()); paint.setTextSize(spToPixels(fontSizeSP)); String viewText = view.getText().toString(); float widthPixels = paint.measureText(viewText); // Increase font size if necessary. if (widthPixels < widthLimitPixels){ while (widthPixels < widthLimitPixels && fontSizeSP <= MAX_SP){ ++fontSizeSP; paint.setTextSize(spToPixels(fontSizeSP)); widthPixels = paint.measureText(viewText); } --fontSizeSP; } // Decrease font size if necessary. else { while (widthPixels > widthLimitPixels || fontSizeSP > MAX_SP) { if (fontSizeSP < MIN_SP) { fontSizeSP = MIN_SP; break; } --fontSizeSP; paint.setTextSize(spToPixels(fontSizeSP)); widthPixels = paint.measureText(viewText); } } view.setTextSize(fontSizeSP); } }; } private float pixelsToSp(float px) { float scaledDensity = getResources().getDisplayMetrics().scaledDensity; return px/scaledDensity; } private float spToPixels(float sp) { float scaledDensity = getResources().getDisplayMetrics().scaledDensity; return sp * scaledDensity; } 

This approach will increase or decrease the font size as needed to fit the text, respecting the MIN_SP and MAX_SP bounds received as parameters.

I wrote a blog post about this.

I created a component called ResizableButton based on Kirill Grouchnikov's blog post about custom components used in the new android market app. I placed the src code here.

On the other hand, mosabua read my post and told me he was going to open source his implementation which was faster than mine. I hope he release it soon enough :)

I found the following to work nicely for me. It doesn't loop and accounts for both height and width. Note that it is important to specify the PX unit when calling setTextSize on the view.

Paint paint = adjustTextSize(getPaint(), numChars, maxWidth, maxHeight); setTextSize(TypedValue.COMPLEX_UNIT_PX,paint.getTextSize()); 

Here is the routine I use, passing in the getPaint() from the view. A 10 character string with a 'wide' character is used to estimate the width independent from the actual string.

private static final String text10="OOOOOOOOOO"; public static Paint adjustTextSize(Paint paint, int numCharacters, int widthPixels, int heightPixels) { float width = paint.measureText(text10)*numCharacters/text10.length(); float newSize = (int)((widthPixels/width)*paint.getTextSize()); paint.setTextSize(newSize); // remeasure with font size near our desired result width = paint.measureText(text10)*numCharacters/text10.length(); newSize = (int)((widthPixels/width)*paint.getTextSize()); paint.setTextSize(newSize); // Check height constraints FontMetricsInt metrics = paint.getFontMetricsInt(); float textHeight = metrics.descent-metrics.ascent; if (textHeight > heightPixels) { newSize = (int)(newSize * (heightPixels/textHeight)); paint.setTextSize(newSize); } return paint; } 

My implementation is a bit more complex, but comes with the following goodies:

• takes the available width and available height into account
• works with single line and multiline labels
• uses ellipsis in case the minimum font size is hit
• since the internal text representation is changed, remembers the originally set text in a separate variable
• ensures that the canvas is always only as big as it needs to be, while it uses all the available height of the parent

/** * Text view that auto adjusts text size to fit within the view. If the text * size equals the minimum text size and still does not fit, append with an * ellipsis. * * Based on the original work from Chase Colburn * &lt;http://stackoverflow.com/a/5535672/305532> * * @author Thomas Keller &lt;[email protected]> */ public class AutoResizeTextView extends TextView { // in dip private static final int MIN_TEXT_SIZE = 20; private static final boolean SHRINK_TEXT_SIZE = true; private static final char ELLIPSIS = '\u2026'; private static final float LINE_SPACING_MULTIPLIER_MULTILINE = 0.8f; private static final float LINE_SPACING_MULTIPLIER_SINGLELINE = 1f; private static final float LINE_SPACING_EXTRA = 0.0f; private CharSequence mOriginalText; // temporary upper bounds on the starting text size private float mMaxTextSize; // lower bounds for text size private float mMinTextSize; // determines whether we're currently in the process of measuring ourselves, // so we do not enter onMeasure recursively private boolean mInMeasure = false; // if the text size should be shrinked or if the text size should be kept // constant and only characters should be removed to hit the boundaries private boolean mShrinkTextSize; public AutoResizeTextView(Context context) { this(context, null); init(context, null); } public AutoResizeTextView(Context context, AttributeSet attrs) { this(context, attrs, 0); init(context, attrs); } public AutoResizeTextView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); init(context, attrs); } private void init(Context context, AttributeSet attrs) { // the current text size is used as maximum text size we can apply to // our widget mMaxTextSize = getTextSize(); if (attrs != null) { TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.AutoResizeTextView); mMinTextSize = a.getFloat(R.styleable.AutoResizeTextView_minFontSize, MIN_TEXT_SIZE); mShrinkTextSize = a.getBoolean(R.styleable.AutoResizeTextView_shrinkTextSize, SHRINK_TEXT_SIZE); a.recycle(); } } @Override public void setTextSize(float size) { mMaxTextSize = size; super.setTextSize(size); } /** * Returns the original, unmodified text of this widget * * @return */ public CharSequence getOriginalText() { // text has not been resized yet if (mOriginalText == null) { return getText(); } return mOriginalText; } @Override public void setText(CharSequence text, BufferType type) { if (!mInMeasure) { mOriginalText = text.toString(); } super.setText(text, type); } @SuppressLint("DrawAllocation") @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { mInMeasure = true; try { int availableWidth = MeasureSpec.getSize(widthMeasureSpec) - getCompoundPaddingLeft() - getCompoundPaddingRight(); int availableHeight = MeasureSpec.getSize(heightMeasureSpec) - getCompoundPaddingTop() - getCompoundPaddingBottom(); // Do not resize if the view does not have dimensions or there is no // text if (mOriginalText == null || mOriginalText.length() == 0 || availableWidth <= 0) { return; } TextPaint textPaint = getPaint(); // start with the recorded max text size float targetTextSize = mMaxTextSize; String originalText = mOriginalText.toString(); String finalText = originalText; Rect textSize = getTextSize(originalText, textPaint, targetTextSize); boolean textExceedsBounds = textSize.height() > availableHeight || textSize.width() > availableWidth; if (mShrinkTextSize && textExceedsBounds) { // check whether all lines can be rendered in the available // width / height without violating the bounds of the parent and // without using a text size that is smaller than the minimum // text size float heightMultiplier = availableHeight / (float) textSize.height(); float widthMultiplier = availableWidth / (float) textSize.width(); float multiplier = Math.min(heightMultiplier, widthMultiplier); targetTextSize = Math.max(targetTextSize * multiplier, mMinTextSize); // measure again textSize = getTextSize(finalText, textPaint, targetTextSize); } // we cannot shrink the height further when we hit the available // height, but we can shrink the width by applying an ellipsis on // each line if (textSize.width() > availableWidth) { StringBuilder modifiedText = new StringBuilder(); String lines[] = originalText.split(System.getProperty("line.separator")); for (int i = 0; i < lines.length; i++) { modifiedText.append(resizeLine(textPaint, lines[i], availableWidth)); // add the separator back to all but the last processed line if (i != lines.length - 1) { modifiedText.append(System.getProperty("line.separator")); } } finalText = modifiedText.toString(); // measure again textSize = getTextSize(finalText, textPaint, targetTextSize); } textPaint.setTextSize(targetTextSize); boolean isMultiline = finalText.indexOf('\n') > -1; // do not include extra font padding (for accents, ...) for // multiline texts, this will prevent proper placement with // Gravity.CENTER_VERTICAL if (isMultiline) { setLineSpacing(LINE_SPACING_EXTRA, LINE_SPACING_MULTIPLIER_MULTILINE); setIncludeFontPadding(false); } else { setLineSpacing(LINE_SPACING_EXTRA, LINE_SPACING_MULTIPLIER_SINGLELINE); setIncludeFontPadding(true); } // according to // <http://code.google.com/p/android/issues/detail?id=22493> // we have to add a unicode character to trigger the text centering // in ICS. this particular character is known as "zero-width" and // does no harm. setText(finalText + "\u200B"); int measuredWidth = textSize.width() + getCompoundPaddingLeft() + getCompoundPaddingRight(); int measuredHeight = textSize.height() + getCompoundPaddingTop() + getCompoundPaddingBottom(); // expand the view to the parent's height in case it is smaller or // to the minimum height that has been set // FIXME: honor the vertical measure mode (EXACTLY vs AT_MOST) here // somehow measuredHeight = Math.max(measuredHeight, MeasureSpec.getSize(heightMeasureSpec)); setMeasuredDimension(measuredWidth, measuredHeight); } finally { mInMeasure = false; } } private Rect getTextSize(String text, TextPaint textPaint, float textSize) { textPaint.setTextSize(textSize); // StaticLayout depends on a given width in which it should lay out the // text (and optionally also split into separate lines). // Therefor we calculate the current text width manually and start with // a fake (read: maxmimum) width for the height calculation. // We do _not_ use layout.getLineWidth() here since this returns // slightly smaller numbers and therefor would lead to exceeded text box // drawing. StaticLayout layout = new StaticLayout(text, textPaint, Integer.MAX_VALUE, Alignment.ALIGN_NORMAL, 1f, 0f, true); int textWidth = 0; String lines[] = text.split(System.getProperty("line.separator")); for (int i = 0; i < lines.length; ++i) { textWidth = Math.max(textWidth, measureTextWidth(textPaint, lines[i])); } return new Rect(0, 0, textWidth, layout.getHeight()); } private String resizeLine(TextPaint textPaint, String line, int availableWidth) { checkArgument(line != null && line.length() > 0, "expected non-empty string"); int textWidth = measureTextWidth(textPaint, line); int lastDeletePos = -1; StringBuilder builder = new StringBuilder(line); while (textWidth > availableWidth && builder.length() > 0) { lastDeletePos = builder.length() / 2; builder.deleteCharAt(builder.length() / 2); // don't forget to measure the ellipsis character as well; it // doesn't matter where it is located in the line, it just has to be // there, since there are no (known) ligatures that use this glyph String textToMeasure = builder.toString() + ELLIPSIS; textWidth = measureTextWidth(textPaint, textToMeasure); } if (lastDeletePos > -1) { builder.insert(lastDeletePos, ELLIPSIS); } return builder.toString(); } // there are several methods in Android to determine the text width, namely // getBounds() and measureText(). // The latter works for us the best as it gives us the best / nearest // results without that our text canvas needs to wrap its text later on // again. private int measureTextWidth(TextPaint textPaint, String line) { return Math.round(textPaint.measureText(line)); } } 

[revised on 2012-11-21]

• fixed the placement of the ellipsis (off-by-one error)
• reworked text size calculation; now always the full text including line breaks is measured, to fix problems when the addition of the height of two single measured lines just didn't lead to the same result as the measurement of the height of the text as a whole
• instead of looping to find the smallest available text size, just calculate it after the first measurement

My method is:

public void changeTextSize(int initialSize, TextView tv) { DisplayMetrics displayMetrics = new DisplayMetrics(); getWindowManager().getDefaultDisplay().getMetrics(displayMetrics); double width = displayMetrics.widthPixels / displayMetrics.xdpi; double height = displayMetrics.heightPixels / displayMetrics.ydpi; Log.i("LOG", "The width of the tested emulator is: " + width); Log.i("LOG", "The height of the tested emulator is: " + height); double scale = Math.min(width / 2.25, height / 4.0); //See the logcat >>> width = 2.25 and heigt = 4.0 tv.setTextSize(TypedValue.COMPLEX_UNIT_SP, (int) (initialSize * scale)); } 

For example:

changeTextSize(16, findViewById(R.id.myTextView)); changeTextSize(12, findViewById(R.id.myEditText)); 

Here's an enumeration of what else I've found for anyone still searching:

1) Here's a solution that recursively re-paints the textview until it fits. This means literally watching your text shrink into place, but at least it fits when it's done. The code will need some tweaking to implement, but it's mostly there.

2) You can try hacking together a custom solution like this, or dunni's class in this, which is what I did using the getPaint().measureText(str) to search for the right size, but it got a lot messier since I need it to wrap only on whitespace...

3) You can keep searching- I've tried more alternatives than I can count. Ted's advice on StaticLayout hasn't paid off for me but maybe there's something there; I tried using the StaticLayout.getEllipsis(line) to determine if text was going off screen, to no effect. See my (presently un-answered) post about that here.

I needed a specific solution. I have got an edittext and textview in my layout. The textview is fixed height and width. When the user starts to type in the edittext, the text should immediately appear in the textview. The text in the textfield should auto - resize to fit the textview. So I updated Chase's solution to work for me. So when the text changes in the textview, resizing starts. The difference between mine and Chase's soluton: resizing is done even if the user DELETE some chars. I hope it can help someone.

public class TextFitTextView extends TextView { // Minimum text size for this text view public static final float MIN_TEXT_SIZE = 10; // Maximum text size for this text view - if it is 0, then the text acts // like match_parent public static final float MAX_TEXT_SIZE = 0; // Our ellipse string private static final String mEllipsis = "..."; // Text size that is set from code. This acts as a starting point for // resizing private float mTextSize; // Lower bounds for text size private float mMinTextSize = MIN_TEXT_SIZE; // Max bounds for text size private float mMaxTextSize = MAX_TEXT_SIZE; // Text view line spacing multiplier private float mSpacingMult = 1.0f; // Text view additional line spacing private float mSpacingAdd = 0.0f; // Add ellipsis to text that overflows at the smallest text size private boolean mAddEllipsis = true; // Add ellipsis to text that overflows at the smallest text size private int heightLimit; private int widthLimit; // Default constructor override public TextFitTextView(Context context) { this(context, null); } // Default constructor when inflating from XML file public TextFitTextView(Context context, AttributeSet attrs) { this(context, attrs, 0); } // Default constructor override public TextFitTextView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); mTextSize = getTextSize(); } /** * When text changes resize the text size. */ @Override protected void onTextChanged(final CharSequence text, final int start, final int before, final int after) { // if we are adding new chars to text if (before <= after && after != 1) { resizeText(true); // now we are deleting chars } else { resizeText(false); } } /** * Override the set text size to update our internal reference values */ @Override public void setTextSize(float size) { super.setTextSize(size); mTextSize = getTextSize(); } /** * Override the set text size to update our internal reference values */ @Override public void setTextSize(int unit, float size) { super.setTextSize(unit, size); mTextSize = getTextSize(); } /** * Override the set line spacing to update our internal reference values */ @Override public void setLineSpacing(float add, float mult) { super.setLineSpacing(add, mult); mSpacingMult = mult; mSpacingAdd = add; } /** * Set the lower text size limit and invalidate the view * * @param minTextSize */ public void setMinTextSize(float minTextSize) { mMinTextSize = minTextSize; requestLayout(); invalidate(); } /** * Return lower text size limit * * @return */ public float getMinTextSize() { return mMinTextSize; } /** * Set flag to add ellipsis to text that overflows at the smallest text size * * @param addEllipsis */ public void setAddEllipsis(boolean addEllipsis) { mAddEllipsis = addEllipsis; } /** * Return flag to add ellipsis to text that overflows at the smallest text * size * * @return */ public boolean getAddEllipsis() { return mAddEllipsis; } /** * Get width and height limits */ @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { if (widthLimit == 0 && heightLimit == 0) { widthLimit = (right - left) - getCompoundPaddingLeft() - getCompoundPaddingRight(); heightLimit = (bottom - top) - getCompoundPaddingBottom() - getCompoundPaddingTop(); } super.onLayout(changed, left, top, right, bottom); } /** * Resize the text size with specified width and height * * @param width * @param height */ public void resizeText(boolean increase) { CharSequence text = getText(); // Do not resize if the view does not have dimensions or there is no // text if (text == null || text.length() == 0 || heightLimit <= 0 || widthLimit <= 0 || mTextSize == 0) { return; } // Get the text view's paint object TextPaint textPaint = getPaint(); // Get the required text height int textHeight = getTextHeight(text, textPaint, widthLimit, mTextSize); // If the text length is increased // Until we either fit within our text view or we had reached our min // text size, incrementally try smaller sizes if (increase) { while (textHeight > heightLimit && mTextSize > mMinTextSize) { mTextSize = Math.max(mTextSize - 2, mMinTextSize); textHeight = getTextHeight(text, textPaint, widthLimit, mTextSize); } } // text length has been decreased else { // if max test size is set then add it to while condition if (mMaxTextSize != 0) { while (textHeight < heightLimit && mTextSize <= mMaxTextSize) { mTextSize = mTextSize + 2; textHeight = getTextHeight(text, textPaint, widthLimit, mTextSize); } } else { while (textHeight < heightLimit) { mTextSize = mTextSize + 2; textHeight = getTextHeight(text, textPaint, widthLimit, mTextSize); } } mTextSize = textHeight > heightLimit ? mTextSize - 2 : mTextSize; } // If we had reached our minimum text size and still don't fit, append // an ellipsis if (mAddEllipsis && mTextSize == mMinTextSize && textHeight > heightLimit) { // Draw using a static layout TextPaint paint = new TextPaint(textPaint); StaticLayout layout = new StaticLayout(text, paint, widthLimit, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, false); // Check that we have a least one line of rendered text if (layout.getLineCount() > 0) { // Since the line at the specific vertical position would be cut // off, // we must trim up to the previous line int lastLine = layout.getLineForVertical(heightLimit) - 1; // If the text would not even fit on a single line, clear it if (lastLine < 0) { setText(""); } // Otherwise, trim to the previous line and add an ellipsis else { int start = layout.getLineStart(lastLine); int end = layout.getLineEnd(lastLine); float lineWidth = layout.getLineWidth(lastLine); float ellipseWidth = paint.measureText(mEllipsis); // Trim characters off until we have enough room to draw the // ellipsis while (widthLimit < lineWidth + ellipseWidth) { lineWidth = paint.measureText(text.subSequence(start, --end + 1).toString()); } setText(text.subSequence(0, end) + mEllipsis); } } } // Some devices try to auto adjust line spacing, so force default line // spacing // and invalidate the layout as a side effect setTextSize(TypedValue.COMPLEX_UNIT_PX, mTextSize); setLineSpacing(mSpacingAdd, mSpacingMult); } // Set the text size of the text paint object and use a static layout to // render text off screen before measuring private int getTextHeight(CharSequence source, TextPaint originalPaint, int width, float textSize) { // Update the text paint object TextPaint paint = new TextPaint(originalPaint); paint.setTextSize(textSize); // Measure using a static layout StaticLayout layout = new StaticLayout(source, paint, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true); return layout.getHeight(); } } 

Providing this version of top answer rewritten on C# for those who codes on Xamarin.Android. Worked for me well.

 /** * DO WHAT YOU WANT TO PUBLIC LICENSE * Version 2, December 2004 * * Copyright (C) 2004 Sam Hocevar <[email protected]> * * Everyone is permitted to copy and distribute verbatim or modified * copies of this license document, and changing it is allowed as long * as the name is changed. * * DO WHAT YOU WANT TO PUBLIC LICENSE * TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION * * 0. You just DO WHAT YOU WANT TO. */ using System; using Android.Content; using Android.Runtime; using Android.Text; using Android.Util; using Android.Widget; using Java.Lang; namespace App.GuestGuide.Droid.Controls { public class OnTextResizeEventArgs : EventArgs { public TextView TextView { get; set; } public float OldSize { get; set; } public float NewSize { get; set; } } /// <inheritdoc /> /// <summary> /// Text view that auto adjusts text size to fit within the view. /// If the text size equals the minimum text size and still does not /// fit, append with an ellipsis. /// </summary> public class AutoResizeTextView : TextView { /// <summary> /// Minimum text size for this text view /// </summary> public static float MIN_TEXT_SIZE = 10; /// <summary> /// Our ellipse string /// </summary> private const string Ellipsis = "..."; private float _mMaxTextSize; private float _mMinTextSize = MIN_TEXT_SIZE; /// <summary> /// Register subscriber to receive resize notifications /// </summary> public event EventHandler<OnTextResizeEventArgs> OnTextResize; /// <summary> /// Flag for text and/or size changes to force a resize /// </summary> private bool _needsResize; /// <summary> /// Text size that is set from code. This acts as a starting point for resizing /// </summary> private float _textSize; /// <summary> /// Text view line spacing multiplier /// </summary> private float _spacingMult = 1.0f; /// <summary> /// Text view additional line spacing /// </summary> private float _spacingAdd; /// <summary> /// Add ellipsis to text that overflows at the smallest text size /// </summary> public bool ShouldAddEllipsis { get; set; } /// <inheritdoc /> /// <summary> /// Override the set text size to update our internal reference values /// </summary> public override float TextSize { get => base.TextSize; set { base.TextSize = value; _textSize = TextSize; } } /// <summary> /// Temporary upper bounds on the starting text size /// </summary> public float MaxTextSize { get => _mMaxTextSize; // Set the upper text size limit and invalidate the view set { _mMaxTextSize = value; RequestLayout(); Invalidate(); } } /// <summary> /// Lower bounds for text size /// </summary> public float MinTextSize { get => _mMinTextSize; //Set the lower text size limit and invalidate the view set { _mMinTextSize = value; RequestLayout(); Invalidate(); } } public AutoResizeTextView(Context context) : this(context, null) { } public AutoResizeTextView(Context context, IAttributeSet attrs) : this(context, attrs, 0) { } public AutoResizeTextView(Context context, IAttributeSet attrs, int defStyleAttr) : base(context, attrs, defStyleAttr) { _textSize = TextSize; } public AutoResizeTextView(Context context, IAttributeSet attrs, int defStyleAttr, int defStyleRes) : base(context, attrs, defStyleAttr, defStyleRes) { _textSize = TextSize; } protected AutoResizeTextView(IntPtr javaReference, JniHandleOwnership transfer) : base(javaReference, transfer) { _textSize = TextSize; } /// <inheritdoc /> /// <summary> /// When text changes, set the force resize flag to true and reset the text size. /// </summary> /// <param name="text"></param> /// <param name="start"></param> /// <param name="lengthBefore"></param> /// <param name="lengthAfter"></param> protected override void OnTextChanged(ICharSequence text, int start, int lengthBefore, int lengthAfter) { _needsResize = true; // Since this view may be reused, it is good to reset the text size ResetTextSize(); } /// <inheritdoc /> /// <summary> /// If the text view size changed, set the force resize flag to true /// </summary> /// <param name="w"></param> /// <param name="h"></param> /// <param name="oldw"></param> /// <param name="oldh"></param> protected override void OnSizeChanged(int w, int h, int oldw, int oldh) { if (w != oldw || h != oldh) { _needsResize = true; } } public override void SetTextSize([GeneratedEnum] ComplexUnitType unit, float size) { base.SetTextSize(unit, size); _textSize = TextSize; } /// <inheritdoc /> /// <summary> /// Override the set line spacing to update our internal reference values /// </summary> /// <param name="add"></param> /// <param name="mult"></param> public override void SetLineSpacing(float add, float mult) { base.SetLineSpacing(add, mult); _spacingMult = mult; _spacingAdd = add; } /// <summary> /// Reset the text to the original size /// </summary> public void ResetTextSize() { if (_textSize > 0) { base.SetTextSize(ComplexUnitType.Px, _textSize); _mMaxTextSize = _textSize; } } /// <inheritdoc /> /// <summary> /// Resize text after measuring /// </summary> /// <param name="changed"></param> /// <param name="left"></param> /// <param name="top"></param> /// <param name="right"></param> /// <param name="bottom"></param> protected override void OnLayout(bool changed, int left, int top, int right, int bottom) { if (changed || _needsResize) { var widthLimit = (right - left) - CompoundPaddingLeft - CompoundPaddingRight; var heightLimit = (bottom - top) - CompoundPaddingBottom - CompoundPaddingTop; ResizeText(widthLimit, heightLimit); } base.OnLayout(changed, left, top, right, bottom); } /// <summary> /// Resize the text size with default width and height /// </summary> public void ResizeText() { var heightLimit = Height - PaddingBottom - PaddingTop; var widthLimit = Width - PaddingLeft - PaddingRight; ResizeText(widthLimit, heightLimit); } /// <summary> /// Resize the text size with specified width and height /// </summary> /// <param name="width"></param> /// <param name="height"></param> public void ResizeText(int width, int height) { ICharSequence text = null; if (!string.IsNullOrEmpty(Text)) { text = new Java.Lang.String(Text); } // Do not resize if the view does not have dimensions or there is no text if (text == null || text.Length() == 0 || height <= 0 || width <= 0 || _textSize == 0) { return; } if (TransformationMethod != null) { text = TransformationMethod.GetTransformationFormatted(text, this); } // Get the text view's paint object var textPaint = Paint; // Store the current text size var oldTextSize = textPaint.TextSize; // If there is a max text size set, use the lesser of that and the default text size var targetTextSize = _mMaxTextSize > 0 ? System.Math.Min(_textSize, _mMaxTextSize) : _textSize; // Get the required text height var textHeight = GetTextHeight(text, textPaint, width, targetTextSize); // Until we either fit within our text view or we had reached our min text size, incrementally try smaller sizes while (textHeight > height && targetTextSize > _mMinTextSize) { targetTextSize = System.Math.Max(targetTextSize - 2, _mMinTextSize); textHeight = GetTextHeight(text, textPaint, width, targetTextSize); } // If we had reached our minimum text size and still don't fit, append an ellipsis if (ShouldAddEllipsis && targetTextSize == _mMinTextSize && textHeight > height) { // Draw using a static layout // modified: use a copy of TextPaint for measuring var paint = new TextPaint(textPaint); // Draw using a static layout var layout = new StaticLayout(text, paint, width, Layout.Alignment.AlignNormal, _spacingMult, _spacingAdd, false); // Check that we have a least one line of rendered text if (layout.LineCount > 0) { // Since the line at the specific vertical position would be cut off, // we must trim up to the previous line var lastLine = layout.GetLineForVertical(height) - 1; // If the text would not even fit on a single line, clear it if (lastLine < 0) { Text = string.Empty; } // Otherwise, trim to the previous line and add an ellipsis else { var start = layout.GetLineStart(lastLine); var end = layout.GetLineEnd(lastLine); var lineWidth = layout.GetLineWidth(lastLine); var ellipseWidth = textPaint.MeasureText(Ellipsis); // Trim characters off until we have enough room to draw the ellipsis while (width < lineWidth + ellipseWidth) { lineWidth = textPaint.MeasureText(text.SubSequence(start, --end + 1)); } Text = text.SubSequence(0, end) + Ellipsis; } } } // Some devices try to auto adjust line spacing, so force default line spacing // and invalidate the layout as a side effect SetTextSize(ComplexUnitType.Px, targetTextSize); SetLineSpacing(_spacingAdd, _spacingMult); var notifyArgs = new OnTextResizeEventArgs { TextView = this, NewSize = targetTextSize, OldSize = oldTextSize }; // Notify the listener if registered OnTextResize?.Invoke(this, notifyArgs); // Reset force resize flag _needsResize = false; } /// <summary> /// Set the text size of the text paint object and use a static layout to render text off screen before measuring /// </summary> /// <param name="source"></param> /// <param name="paint"></param> /// <param name="width"></param> /// <param name="textSize"></param> /// <returns></returns> private int GetTextHeight(ICharSequence source, TextPaint paint, int width, float textSize) { // modified: make a copy of the original TextPaint object for measuring // (apparently the object gets modified while measuring, see also the // docs for TextView.getPaint() (which states to access it read-only) // Update the text paint object var paintCopy = new TextPaint(paint) { TextSize = textSize }; // Measure using a static layout var layout = new StaticLayout(source, paintCopy, width, Layout.Alignment.AlignNormal, _spacingMult, _spacingAdd, true); return layout.Height; } } } 

You can use the android.text.StaticLayout class for this. That's what TextView uses internally.

I just created the following method (based on the ideas of Chase) which might help you if you want to draw text to any canvas:

private static void drawText(Canvas canvas, int xStart, int yStart, int xWidth, int yHeigth, String textToDisplay, TextPaint paintToUse, float startTextSizeInPixels, float stepSizeForTextSizeSteps) { // Text view line spacing multiplier float mSpacingMult = 1.0f; // Text view additional line spacing float mSpacingAdd = 0.0f; StaticLayout l = null; do { paintToUse.setTextSize(startTextSizeInPixels); startTextSizeInPixels -= stepSizeForTextSizeSteps; l = new StaticLayout(textToDisplay, paintToUse, xWidth, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true); } while (l.getHeight() > yHeigth); int textCenterX = xStart + (xWidth / 2); int textCenterY = (yHeigth - l.getHeight()) / 2; canvas.save(); canvas.translate(textCenterX, textCenterY); l.draw(canvas); canvas.restore(); } 

This could be used e.g. in any onDraw() method of any custom view.

Here's yet another solution, just for kicks. It's probably not very efficient, but it does cope with both height and width of the text, and with marked-up text.

@Override protected void onMeasure(final int widthMeasureSpec, final int heightMeasureSpec) { if ((MeasureSpec.getMode(widthMeasureSpec) != MeasureSpec.UNSPECIFIED) && (MeasureSpec.getMode(heightMeasureSpec) != MeasureSpec.UNSPECIFIED)) { final float desiredWidth = MeasureSpec.getSize(widthMeasureSpec); final float desiredHeight = MeasureSpec.getSize(heightMeasureSpec); float textSize = getTextSize(); float lastScale = Float.NEGATIVE_INFINITY; while (textSize > MINIMUM_AUTO_TEXT_SIZE_PX) { // Measure how big the textview would like to be with the current text size. super.onMeasure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED); // Calculate how much we'd need to scale it to fit the desired size, and // apply that scaling to the text size as an estimate of what we need. final float widthScale = desiredWidth / getMeasuredWidth(); final float heightScale = desiredHeight / getMeasuredHeight(); final float scale = Math.min(widthScale, heightScale); // If we don't need to shrink the text, or we don't seem to be converging, we're done. if ((scale >= 1f) || (scale <= lastScale)) { break; } // Shrink the text size and keep trying. textSize = Math.max((float) Math.floor(scale * textSize), MINIMUM_AUTO_TEXT_SIZE_PX); setTextSize(TypedValue.COMPLEX_UNIT_PX, textSize); lastScale = scale; } } super.onMeasure(widthMeasureSpec, heightMeasureSpec); } 

I combined some of the above suggestions to make one that scales up and down, with bisection method. It also scales within the width.

/** * DO WHAT YOU WANT TO PUBLIC LICENSE * Version 2, December 2004 * * Copyright (C) 2004 Sam Hocevar <[email protected]> * * Everyone is permitted to copy and distribute verbatim or modified * copies of this license document, and changing it is allowed as long * as the name is changed. * * DO WHAT YOU WANT TO PUBLIC LICENSE * TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION * * 0. You just DO WHAT YOU WANT TO. */ import android.content.Context; import android.text.Layout.Alignment; import android.text.StaticLayout; import android.text.TextPaint; import android.util.AttributeSet; import android.util.TypedValue; import android.widget.TextView; /** * Text view that auto adjusts text size to fit within the view. If the text * size equals the minimum text size and still does not fit, append with an * ellipsis. * * @author Chase Colburn * @since Apr 4, 2011 */ public class AutoResizeTextView extends TextView { // Minimum text size for this text view public static final float MIN_TEXT_SIZE = 10; // Minimum text size for this text view public static final float MAX_TEXT_SIZE = 128; private static final int BISECTION_LOOP_WATCH_DOG = 30; // Interface for resize notifications public interface OnTextResizeListener { public void onTextResize(TextView textView, float oldSize, float newSize); } // Our ellipse string private static final String mEllipsis = "..."; // Registered resize listener private OnTextResizeListener mTextResizeListener; // Flag for text and/or size changes to force a resize private boolean mNeedsResize = false; // Text size that is set from code. This acts as a starting point for // resizing private float mTextSize; // Temporary upper bounds on the starting text size private float mMaxTextSize = MAX_TEXT_SIZE; // Lower bounds for text size private float mMinTextSize = MIN_TEXT_SIZE; // Text view line spacing multiplier private float mSpacingMult = 1.0f; // Text view additional line spacing private float mSpacingAdd = 0.0f; // Add ellipsis to text that overflows at the smallest text size private boolean mAddEllipsis = true; // Default constructor override public AutoResizeTextView(Context context) { this(context, null); } // Default constructor when inflating from XML file public AutoResizeTextView(Context context, AttributeSet attrs) { this(context, attrs, 0); } // Default constructor override public AutoResizeTextView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); mTextSize = getTextSize(); } /** * When text changes, set the force resize flag to true and reset the text * size. */ @Override protected void onTextChanged(final CharSequence text, final int start, final int before, final int after) { mNeedsResize = true; // Since this view may be reused, it is good to reset the text size resetTextSize(); } /** * If the text view size changed, set the force resize flag to true */ @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { if (w != oldw || h != oldh) { mNeedsResize = true; } } /** * Register listener to receive resize notifications * * @param listener */ public void setOnResizeListener(OnTextResizeListener listener) { mTextResizeListener = listener; } /** * Override the set text size to update our internal reference values */ @Override public void setTextSize(float size) { super.setTextSize(size); mTextSize = getTextSize(); } /** * Override the set text size to update our internal reference values */ @Override public void setTextSize(int unit, float size) { super.setTextSize(unit, size); mTextSize = getTextSize(); } /** * Override the set line spacing to update our internal reference values */ @Override public void setLineSpacing(float add, float mult) { super.setLineSpacing(add, mult); mSpacingMult = mult; mSpacingAdd = add; } /** * Set the upper text size limit and invalidate the view * * @param maxTextSize */ public void setMaxTextSize(float maxTextSize) { mMaxTextSize = maxTextSize; requestLayout(); invalidate(); } /** * Return upper text size limit * * @return */ public float getMaxTextSize() { return mMaxTextSize; } /** * Set the lower text size limit and invalidate the view * * @param minTextSize */ public void setMinTextSize(float minTextSize) { mMinTextSize = minTextSize; requestLayout(); invalidate(); } /** * Return lower text size limit * * @return */ public float getMinTextSize() { return mMinTextSize; } /** * Set flag to add ellipsis to text that overflows at the smallest text size * * @param addEllipsis */ public void setAddEllipsis(boolean addEllipsis) { mAddEllipsis = addEllipsis; } /** * Return flag to add ellipsis to text that overflows at the smallest text * size * * @return */ public boolean getAddEllipsis() { return mAddEllipsis; } /** * Reset the text to the original size */ public void resetTextSize() { if (mTextSize > 0) { super.setTextSize(TypedValue.COMPLEX_UNIT_PX, mTextSize); // mMaxTextSize = mTextSize; } } /** * Resize text after measuring */ @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { if (changed || mNeedsResize) { int widthLimit = (right - left) - getCompoundPaddingLeft() - getCompoundPaddingRight(); int heightLimit = (bottom - top) - getCompoundPaddingBottom() - getCompoundPaddingTop(); resizeText(widthLimit, heightLimit); } super.onLayout(changed, left, top, right, bottom); } /** * Resize the text size with default width and height */ public void resizeText() { // Height and width with a padding as a percentage of height int heightLimit = getHeight() - getPaddingBottom() - getPaddingTop(); int widthLimit = getWidth() - getPaddingLeft() - getPaddingRight(); resizeText(widthLimit, heightLimit); } /** * Resize the text size with specified width and height * * @param width * @param height */ public void resizeText(int width, int height) { CharSequence text = getText(); // Do not resize if the view does not have dimensions or there is no // text if (text == null || text.length() == 0 || height <= 0 || width <= 0 || mTextSize == 0) { return; } // Get the text view's paint object TextPaint textPaint = getPaint(); // Store the current text size float oldTextSize = textPaint.getTextSize(); // Bisection method: fast & precise float lower = mMinTextSize; float upper = mMaxTextSize; int loop_counter = 1; float targetTextSize = (lower + upper) / 2; int textHeight = getTextHeight(text, textPaint, width, targetTextSize); int textWidth = getTextWidth(text, textPaint, width, targetTextSize); while (loop_counter < BISECTION_LOOP_WATCH_DOG && upper - lower > 1) { targetTextSize = (lower + upper) / 2; textHeight = getTextHeight(text, textPaint, width, targetTextSize); textWidth = getTextWidth(text, textPaint, width, targetTextSize); if (textHeight > (height) || textWidth > (width)) upper = targetTextSize; else lower = targetTextSize; loop_counter++; } targetTextSize = lower; textHeight = getTextHeight(text, textPaint, width, targetTextSize); // If we had reached our minimum text size and still don't fit, append // an ellipsis if (mAddEllipsis && targetTextSize == mMinTextSize && textHeight > height) { // Draw using a static layout // modified: use a copy of TextPaint for measuring TextPaint paintCopy = new TextPaint(textPaint); paintCopy.setTextSize(targetTextSize); StaticLayout layout = new StaticLayout(text, paintCopy, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, false); // Check that we have a least one line of rendered text if (layout.getLineCount() > 0) { // Since the line at the specific vertical position would be cut // off, // we must trim up to the previous line int lastLine = layout.getLineForVertical(height) - 1; // If the text would not even fit on a single line, clear it if (lastLine < 0) { setText(""); } // Otherwise, trim to the previous line and add an ellipsis else { int start = layout.getLineStart(lastLine); int end = layout.getLineEnd(lastLine); float lineWidth = layout.getLineWidth(lastLine); float ellipseWidth = paintCopy.measureText(mEllipsis); // Trim characters off until we have enough room to draw the // ellipsis while (width < lineWidth + ellipseWidth) { lineWidth = paintCopy.measureText(text.subSequence( start, --end + 1).toString()); } setText(text.subSequence(0, end) + mEllipsis); } } } // Some devices try to auto adjust line spacing, so force default line // spacing // and invalidate the layout as a side effect setTextSize(TypedValue.COMPLEX_UNIT_PX, targetTextSize); setLineSpacing(mSpacingAdd, mSpacingMult); // Notify the listener if registered if (mTextResizeListener != null) { mTextResizeListener.onTextResize(this, oldTextSize, targetTextSize); } // Reset force resize flag mNeedsResize = false; } // Set the text size of the text paint object and use a static layout to // render text off screen before measuring private int getTextHeight(CharSequence source, TextPaint originalPaint, int width, float textSize) { // modified: make a copy of the original TextPaint object for measuring // (apparently the object gets modified while measuring, see also the // docs for TextView.getPaint() (which states to access it read-only) TextPaint paint = new TextPaint(originalPaint); // Update the text paint object paint.setTextSize(textSize); // Measure using a static layout StaticLayout layout = new StaticLayout(source, paint, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true); return layout.getHeight(); } // Set the text size of the text paint object and use a static layout to // render text off screen before measuring private int getTextWidth(CharSequence source, TextPaint originalPaint, int width, float textSize) { // Update the text paint object TextPaint paint = new TextPaint(originalPaint); // Draw using a static layout paint.setTextSize(textSize); StaticLayout layout = new StaticLayout(source, paint, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true); return (int) layout.getLineWidth(0); } } 

I have use code from chase and M-WaJeEh and I found some advantage & disadvantage here

from chase

Advantage:

• it's perfect for 1 line TextView

Disadvantage:

• if it's more than 1 line with custom font some of text will disappear

• if it's enable ellipse, it didn't prepare space for ellipse

• if it's custom font (typeface), it didn't support

from M-WaJeEh

Advantage:

• it's perfect for multi-line

Disadvantage:

• if set height as wrap-content, this code will start from minimum size and it will reduce to smallest as it can, not from the setSize and reduce by the limited width

• if it's custom font (typeface), it didn't support

The problem is about how to have this feature on Button; For TextView it's easy and works very well by following the official document here.

Style.xml:

 <style name="Widget.Button.CustomStyle" parent="Widget.MaterialComponents.Button"> <item name="android:minHeight">50dp</item> <item name="android:maxWidth">300dp</item> <item name="android:textStyle">bold</item> <item name="android:textSize">16sp</item> <item name="backgroundTint">@color/white</item> <item name="cornerRadius">25dp</item> <item name="autoSizeTextType">uniform</item> <item name="autoSizeMinTextSize">10sp</item> <item name="autoSizeMaxTextSize">16sp</item> <item name="autoSizeStepGranularity">2sp</item> <item name="android:maxLines">1</item> <item name="android:textColor">@color/colorPrimary</item> <item name="android:insetTop">0dp</item> <item name="android:insetBottom">0dp</item> <item name="android:lineSpacingExtra">4sp</item> <item name="android:gravity">center</item> </style> 

Usage:

<com.google.android.material.button.MaterialButton android:id="@+id/blah" style="@style/Widget.Button.CustomStyle" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginStart="16dp" android:layout_marginEnd="16dp" android:text="Your long text, to the infinity and beyond!!! Why not :)" /> 

Result:

I have found another solution not mentioned here:

android:justificationMode="inter_word" 

This will evenly spread your strings wrt the width of your TextView.

This solutions works for us:

public class CustomFontButtonTextFit extends CustomFontButton { private final float DECREMENT_FACTOR = .1f; public CustomFontButtonTextFit(Context context) { super(context); } public CustomFontButtonTextFit(Context context, AttributeSet attrs) { super(context, attrs); } public CustomFontButtonTextFit(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } private synchronized void refitText(String text, int textWidth) { if (textWidth > 0) { float availableWidth = textWidth - this.getPaddingLeft() - this.getPaddingRight(); TextPaint tp = getPaint(); Rect rect = new Rect(); tp.getTextBounds(text, 0, text.length(), rect); float size = rect.width(); while(size > availableWidth) { setTextSize( getTextSize() - DECREMENT_FACTOR ); tp = getPaint(); tp.getTextBounds(text, 0, text.length(), rect); size = rect.width(); } } } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); int parentWidth = MeasureSpec.getSize(widthMeasureSpec); int parentHeight = MeasureSpec.getSize(heightMeasureSpec); refitText(this.getText().toString(), parentWidth); if(parentWidth < getSuggestedMinimumWidth()) parentWidth = getSuggestedMinimumWidth(); if(parentHeight < getSuggestedMinimumHeight()) parentHeight = getSuggestedMinimumHeight(); this.setMeasuredDimension(parentWidth, parentHeight); } @Override protected void onTextChanged(final CharSequence text, final int start, final int before, final int after) { super.onTextChanged(text, start, before, after); refitText(text.toString(), this.getWidth()); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { super.onSizeChanged(w, h, oldw, oldh); if (w != oldw) refitText(this.getText().toString(), w); } }