How to make a Scroll Listener for WebView in Android

Question

How to implement the Scroll Listener for WebView in Android

i tried this but its not calling my Log.i on scrolling the webview.

package com.example.webview.full.width; import android.content.Context; import android.util.AttributeSet; import android.util.Log; import android.webkit.WebView; import android.widget.AbsListView; import android.widget.AbsListView.OnScrollListener; public class scorllableWebview extends WebView implements OnScrollListener { Context ctx; AttributeSet atrs; public scorllableWebview(Context context) { super(context); ctx = context; } public scorllableWebview(Context context, AttributeSet atters){ super(context, atters); ctx = context; atrs = atters; } @Override public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { Log.i("onScroll", "Called"); } @Override public void onScrollStateChanged(AbsListView view, int scrollState) { Log.i("onScrollStateChanged", "Called"); } }

Here is my MainActivity.java

package com.example.webview.full.width; import android.app.Activity; import android.app.ProgressDialog; import android.os.Bundle; import android.view.Menu; import android.webkit.WebView; import android.webkit.WebViewClient; import android.widget.Toast; public class MainActivity extends Activity { ProgressDialog progressDialog; scorllableWebview wv; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); wv = (scorllableWebview) findViewById(R.id.scorllableWebview); wv.getSettings().setJavaScriptEnabled(true); wv.getSettings().setBuiltInZoomControls(true); wv.getSettings().supportZoom(); progressDialog = ProgressDialog.show(MainActivity.this, "Loading Book...!", "Please Wait"); progressDialog.setCancelable(true); String htnlString = "<!DOCTYPE html><html><body style = \"text-align:center\"><script type=\"text/javascript\">for(a=1;a<=10;a++)document.write('<img style=\"border-style:dotted;border-width:10px;border-color:black;\"src=\"http://myURL.com/books_snaps/EN567/'+a+'.jpg\" alt=\"Page Not Found\"/>');</script></body></html>"; // width=\"100%\" wv.setWebViewClient(new WebViewClient() { @Override public void onPageFinished(WebView view, String url) { progressDialog.dismiss(); Toast.makeText(MainActivity.this, "Completed", Toast.LENGTH_SHORT).show(); wv.pageUp(true); super.onPageFinished(view, url); } }); wv.loadDataWithBaseURL(null, htnlString, "text/html", "UTF-8", null); } }

and here is my XML file.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" > <com.example.webview.full.width.scorllableWebview xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/scorllableWebview" android:layout_width="match_parent" android:layout_height="match_parent" /> </RelativeLayout>

check this stackoverflow.com/questions/6253444/android-webview-scrollable and stackoverflow.com/questions/10552702/… — baldguy
– baldguy, Commented Feb 7, 2013 at 13:46
its not calling my onScroll method while scrolling the webview. please have a look on my scorllableWebview.java class — Qadir Hussain
– Qadir Hussain, Commented Feb 7, 2013 at 13:58

Komal12 · Accepted Answer · 2018-03-16 10:20:43Z

Something like:

public class ObservableWebView extends WebView { private OnScrollChangedCallback mOnScrollChangedCallback; public ObservableWebView(final Context context) { super(context); } public ObservableWebView(final Context context, final AttributeSet attrs) { super(context, attrs); } public ObservableWebView(final Context context, final AttributeSet attrs, final int defStyle) { super(context, attrs, defStyle); } @Override protected void onScrollChanged(final int l, final int t, final int oldl, final int oldt) { super.onScrollChanged(l, t, oldl, oldt); if(mOnScrollChangedCallback != null) mOnScrollChangedCallback.onScroll(l, t, oldl, oldt); } public OnScrollChangedCallback getOnScrollChangedCallback() { return mOnScrollChangedCallback; } public void setOnScrollChangedCallback(final OnScrollChangedCallback onScrollChangedCallback) { mOnScrollChangedCallback = onScrollChangedCallback; } /** * Impliment in the activity/fragment/view that you want to listen to the webview */ public static interface OnScrollChangedCallback { public void onScroll(int l, int t, int oldl, int oldt); } }

Should work, this is untested but this works for almost every other view in Android.

You would implement like:

wv = (ObservableWebView) findViewById(R.id.scorllableWebview); wv.setOnScrollChangedCallback(new OnScrollChangedCallback(){ public void onScroll(int l, int t, int oldl, int oldt){ if(t> oldt){ //Do stuff System.out.println("Swipe UP"); //Do stuff } else if(t< oldt){ System.out.println("Swipe Down"); } Log.d(TAG,"We Scrolled etc..."); } });

@Chris.Jenkins it didn't worked, it gave an error on line where we used findViewBid of ClassCastException
@AnasReza You have to make sure you implement your ObservableWebView in your XML file. This was implied.
@Chris.Jenkins yeah thanks i implemented in my XML file and it worked fine
nt tek = (int) Math.floor(mTermsCondWV.getContentHeight() * mTermsCondWV.getScale()); if(tek - mTermsCondWV.getScrollY() == mTermsCondWV.getHeight()){ mAgreeBT.setEnabled(true); mAgreeBT.setBackground(ContextCompat.getDrawable(getActivity(),R.drawable.button_bg)); }
Hi its not working for the latest version apis , can you please update answer

Alécio Carvalho · Accepted Answer · 2015-12-05 20:20:59Z

Since API 23, you won't need to do it anymore, you can just use the new OnScrollChangeListener available on all views, including on the WebView. But as you still need to support older versions, you can still use the suggestion from @Chris.Jenkins. I made some adjustments the proposed class to be 'more compatible' with the new OnScrollChangeListener interface:

public class ObservableWebView extends WebView { private OnScrollChangeListener onScrollChangeListener; public ObservableWebView(Context context) { super(context); } public ObservableWebView(Context context, AttributeSet attrs) { super(context, attrs); } public ObservableWebView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); } @Override protected void onScrollChanged(int l, int t, int oldl, int oldt) { super.onScrollChanged(l, t, oldl, oldt); if (onScrollChangeListener != null) { onScrollChangeListener.onScrollChange(this, l, t, oldl, oldt); } } public void setOnScrollChangeListener(OnScrollChangeListener onScrollChangeListener) { this.onScrollChangeListener = onScrollChangeListener; } public OnScrollChangeListener getOnScrollChangeListener() { return onScrollChangeListener; } public interface OnScrollChangeListener { /** * Called when the scroll position of a view changes. * * @param v The view whose scroll position has changed. * @param scrollX Current horizontal scroll origin. * @param scrollY Current vertical scroll origin. * @param oldScrollX Previous horizontal scroll origin. * @param oldScrollY Previous vertical scroll origin. */ void onScrollChange(WebView v, int scrollX, int scrollY, int oldScrollX, int oldScrollY); } }

@LucasS.Müller : you have to support backward version so you can't simply ignore it

coyer · Accepted Answer · 2019-10-24 13:50:43Z

10

There is no need to extend WebView. What about:

webView.getViewTreeObserver().addOnScrollChangedListener(new ViewTreeObserver.OnScrollChangedListener() { @Override public void onScrollChanged() { Log.v(TAG, "+++ scrollchanged "+webView.getScrollY()); } });

answered Oct 24, 2019 at 13:50

coyer

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3 Comments

abir-cse Over a year ago

And what is the webView Scroll Stop Listener ?

user10771503 Over a year ago

workin in 2022 best answer... for webview...

Luis Febro Over a year ago

Still 100% workable in 2023.

Antonis Radz · Accepted Answer · 2019-10-03 11:29:52Z

Here is more elegant Kotlin version of accepted answer

 class ObservableWebView @JvmOverloads constructor( context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0 ) : WebView(context, attrs, defStyleAttr) { var scrollListener: WebViewScrollListener? = null override fun onScrollChanged(scrollX: Int, scrollY: Int, oldScrollX: Int, oldScrollY: Int) { super.onScrollChanged(scrollX, scrollY, oldScrollX, oldScrollY) when { scrollY > oldScrollY -> scrollListener?.onScrollDown() scrollY < oldScrollY -> scrollListener?.onScrollUp() } scrollListener?.onScroll(scrollX, scrollY, oldScrollX, oldScrollY) } } interface WebViewScrollListener{ fun onScroll(scrollX: Int, scrollY: Int, oldScrollX: Int, oldScrollY: Int) fun onScrollDown() fun onScrollUp() }

SamiunNafis · Accepted Answer · 2020-09-15 05:56:43Z

You can try this:

It works for API >= 23 Android Marshmallow

web.setOnScrollChangeListener(new View.OnScrollChangeListener() { @Override public void onScrollChange(View p1, int p2, int p3, int p4, int p5) { Toast.makeText(getApplicationContext, "Scrolled", Toast.LENGTH_SHORT).show(); } });

Ole Pannier · Accepted Answer · 2021-08-07 20:19:50Z

From API 23 (Android - 6.0) , You can implement WebView.OnScrollChangeListener like

 public class MainActivity extends AppCompatActivity implements WebView.OnScrollChangeListener { @Override public void onScrollChange(View v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) { if(oldScrollY < scrollY) { //Scrolling Upwards } else if(oldScrollY > scrollY) { //Scrolling Downwards } } }

MrMaavin · Accepted Answer · 2019-06-07 13:30:51Z

Try this (for all view what you want): Сreate a GestureDetector then a TouchListener and set to a view who scrolling

OnCreate private GestureDetector gestureDetector; gestureDetector = new GestureDetector(this, new GestureDetector.SimpleOnGestureListener() { @Override public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) { if (velocityY < 0) { collapse(frToolBar); } else if (velocityY > 0) { if (frToolBar.getVisibility()==View.GONE) expand(frToolBar); } return super.onFling(e1, e2, velocityX, velocityY); } @Override public boolean onDown(MotionEvent e) { return super.onDown(e); } }); webView.setOnTouchListener((view, motionEvent) -> gestureDetector.onTouchEvent(motionEvent)); Two method - public static void expand(final View v) { v.measure(WindowManager.LayoutParams.MATCH_PARENT, indowManager.LayoutParams.WRAP_CONTENT); // final int targetHeight = v.getMeasuredHeight(); final int targetHeight = v.getHeight(); v.getLayoutParams().height = 1; v.setVisibility(View.VISIBLE); Animation a = new Animation() { @Override protected void applyTransformation(float interpolatedTime, Transformation t) { v.getLayoutParams().height = interpolatedTime == 1 ? WindowManager.LayoutParams.WRAP_CONTENT : (int) (targetHeight * interpolatedTime); v.requestLayout(); } @Override public boolean willChangeBounds() { return true; } }; a.setDuration(300); v.startAnimation(a); } public static void collapse(final View v) { final int initialHeight = v.getMeasuredHeight(); Animation a = new Animation() { @Override protected void applyTransformation(float interpolatedTime, Transformation t) { if (interpolatedTime == 1) { v.setVisibility(View.GONE); } else { v.getLayoutParams().height = initialHeight - (int) (initialHeight * interpolatedTime); v.requestLayout(); } } @Override public boolean willChangeBounds() { return true; } }; a.setDuration(300); v.startAnimation(a); }

Сreate a gesturdektor then touchlister and set to a view who scrolling

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