I would like a ScrollView to start all the way at the bottom. Any methods?
19 Answers
you should run the code inside the scroll.post like this:
scroll.post(new Runnable() { @Override public void run() { scroll.fullScroll(View.FOCUS_DOWN); } }); 6 Comments
scroll.scrollTo(0, scroll.getHeight()); to jump to the bottom, or scroll.smoothScrollTo(0, scroll.getHeight()); for a smoother scrollscrollView.post { scrollView.fullScroll(View.FOCUS_DOWN) }scroll.fullScroll(View.FOCUS_DOWN) also should work.
Put this in a scroll.Post(Runnable run)
Kotlin Code
scrollView.post { scrollView.fullScroll(View.FOCUS_DOWN) } 11 Comments
scroll.fullScroll(View.FOCUS_DOWN) will lead to the change of focus. That will bring some strange behavior when there are more than one focusable views, e.g two EditText. There is another way for this question.
View lastChild = scrollLayout.getChildAt(scrollLayout.getChildCount() - 1); int bottom = lastChild.getBottom() + scrollLayout.getPaddingBottom(); int sy = scrollLayout.getScrollY(); int sh = scrollLayout.getHeight(); int delta = bottom - (sy + sh); scrollLayout.smoothScrollBy(0, delta); This works well.
Kotlin Extension
fun ScrollView.scrollToBottom() { val lastChild = getChildAt(childCount - 1) val bottom = lastChild.bottom + paddingBottom val delta = bottom - (scrollY+ height) smoothScrollBy(0, delta) } Or if you want to further enhance to check whether it is already at the bottom before scrolling, you can do something like this:
fun ScrollView.scrollToBottom() { val lastChild = children.lastOrNull() ?: return val bottom = lastChild.bottom + paddingBottom val currentY = height + scrollY val alreadyAtBottom = bottom <= currentY if (!alreadyAtBottom) { val delta = bottom - currentY smoothScrollBy(0, delta) } else { // already at bottom, do nothing } } 10 Comments
Sometimes scrollView.post doesn't work
scrollView.post(new Runnable() { @Override public void run() { scrollView.fullScroll(ScrollView.FOCUS_DOWN); } }); BUT if you use scrollView.postDelayed, it will definitely work
scrollView.postDelayed(new Runnable() { @Override public void run() { scrollView.fullScroll(ScrollView.FOCUS_DOWN); } },1000); 4 Comments
What worked best for me is
scroll_view.post(new Runnable() { @Override public void run() { // This method works but animates the scrolling // which looks weird on first load // scroll_view.fullScroll(View.FOCUS_DOWN); // This method works even better because there are no animations. scroll_view.scrollTo(0, scroll_view.getBottom()); } }); 1 Comment
I increment to work perfectly.
private void sendScroll(){ final Handler handler = new Handler(); new Thread(new Runnable() { @Override public void run() { try {Thread.sleep(100);} catch (InterruptedException e) {} handler.post(new Runnable() { @Override public void run() { scrollView.fullScroll(View.FOCUS_DOWN); } }); } }).start(); } Note
This answer is a workaround for really old versions of android. Today the postDelayed has no more that bug and you should use it.
5 Comments
postDelayed :)Here is some other ways to scroll to bottom
fun ScrollView.scrollToBottom() { // use this for scroll immediately scrollTo(0, this.getChildAt(0).height) // or this for smooth scroll //smoothScrollBy(0, this.getChildAt(0).height) // or this for **very** smooth scroll //ObjectAnimator.ofInt(this, "scrollY", this.getChildAt(0).height).setDuration(2000).start() } Using
If you scrollview already laid out
my_scroll_view.scrollToBottom() If your scrollview is not finish laid out (eg: you scroll to bottom in Activity onCreate method ...)
my_scroll_view.post { my_scroll_view.scrollToBottom() } Comments
When the view is not loaded yet, you cannot scroll. You can do it 'later' with a post or sleep call as above, but this is not very elegant.
It is better to plan the scroll and do it on the next onLayout(). Example code here:
Comments
One thing to consider is what NOT to set. Make certain your child controls, especially EditText controls, do not have the RequestFocus property set. This may be one of the last interpreted properties on the layout and it will override gravity settings on its parents (the layout or ScrollView).
Comments
Not exactly the answer to the question, but I needed to scroll down as soon as an EditText got the focus. However the accepted answer would make the ET also lose focus right away (to the ScrollView I assume).
My workaround was the following:
emailEt.setOnFocusChangeListener(new View.OnFocusChangeListener() { @Override public void onFocusChange(View v, boolean hasFocus) { if(hasFocus){ Toast.makeText(getActivity(), "got the focus", Toast.LENGTH_LONG).show(); scrollView.postDelayed(new Runnable() { @Override public void run() { scrollView.fullScroll(ScrollView.FOCUS_DOWN); } }, 200); }else { Toast.makeText(getActivity(), "lost the focus", Toast.LENGTH_LONG).show(); } } }); Comments
I actually found that calling fullScroll twice does the trick:
myScrollView.fullScroll(View.FOCUS_DOWN); myScrollView.post(new Runnable() { @Override public void run() { myScrollView.fullScroll(View.FOCUS_DOWN); } }); It may have something to do with the activation of the post() method right after performing the first (unsuccessful) scroll. I think this behavior occurs after any previous method call on myScrollView, so you can try replacing the first fullScroll() method by anything else that may be relevant to you.
Comments
Using there is another cool way to do this with Kotlin coroutines. The advantage of using a coroutine opposed to a Handler with a runnable (post/postDelayed) is that it does not fire up an expensive thread to execute a delayed action.
launch(UI){ delay(300) scrollView.fullScroll(View.FOCUS_DOWN) } It is important to specify the coroutine's HandlerContext as UI otherwise the delayed action might not be called from the UI thread.
Comments
One possible reason of why scroll.fullScroll(View.FOCUS_DOWN) might not work even wrapped in .post() is that the view is not laid out. In this case View.doOnLayout() could be a better option:
scroll.doOnLayout(){ scroll.fullScroll(View.FOCUS_DOWN) } Or, something more elaborated for the brave souls: https://chris.banes.dev/2019/12/03/suspending-views/
Comments
A combination of all answers did the trick for me:
Extension Function PostDelayed
private fun ScrollView.postDelayed( time: Long = 325, // ms block: ScrollView.() -> Unit ) { postDelayed({block()}, time) } Extension Function measureScrollHeight
fun ScrollView.measureScrollHeight(): Int { val lastChild = getChildAt(childCount - 1) val bottom = lastChild.bottom + paddingBottom val delta = bottom - (scrollY+ height) return delta } Extension Function ScrolltoBottom
fun ScrollView.scrollToBottom() { postDelayed { smoothScrollBy(0, measureScrollHeight()) } } Be aware that the minimum delay should be at least 325ms or the scrolling will be buggy (not scrolling to the entire bottom). The larger your delta between the current height and the bottom is, the larger should be the delayed time.
Comments
Some people here said that scrollView.post didn't work.
If you don't want to use scrollView.postDelayed, another option is to use a listener. Here is what I did in another use case :
ViewTreeObserver.OnPreDrawListener viewVisibilityChanged = new ViewTreeObserver.OnPreDrawListener() { @Override public boolean onPreDraw() { if (my_view.getVisibility() == View.VISIBLE) { scroll_view.smoothScrollTo(0, scroll_view.getHeight()); } return true; } }; You can add it to your view this way :
my_view.getViewTreeObserver().addOnPreDrawListener(viewVisibilityChanged); Comments
This works instantly. Without delay.
// wait for the scroll view to be laid out scrollView.post(new Runnable() { public void run() { // then wait for the child of the scroll view (normally a LinearLayout) to be laid out scrollView.getChildAt(0).post(new Runnable() { public void run() { // finally scroll without animation scrollView.scrollTo(0, scrollView.getBottom()); } } } }