When i call setVisibility on view's child while the (parent) view is animated with ViewCompat.postOnAnimation things get broken. (setVisibility doesn't work + some other things get broken).
Question - is there any method of animation or workaround which allows to call setVisibility on child while the parent is animated?
This is very important request and i think not so unusual, because for example http request is returned in random time, and the view can be animated anytime during that.
Code request edit:
Regarding code, it is bit complicated. I will first explain. It is animation in the custom CoordinatorLayout Behavior, clone of the standard BottomSheetBehavior (sliding of sheet from bottom to up).
Animation is launched by calling this:
ViewCompat.postOnAnimation(child, new SettleRunnable(child, targetState));
SettleRunnable is this:
private class SettleRunnable implements Runnable {
private final View mView;
#State
private final int mTargetState;
SettleRunnable(View view, #State int targetState) {
mView = view;
mTargetState = targetState;
}
#Override
public void run() {
if (mViewDragHelper != null && mViewDragHelper.continueSettling(true)) {
ViewCompat.postOnAnimation(mView, this);
} else {
setStateInternal(mTargetState);
}
}
}
So as you can see, all the animation movement is done by mViewDragHelper.continueSettling. Drag helper is standard class ViewDragHelper.
ViewDragHelper.continueSettling looks like this
public boolean continueSettling(boolean deferCallbacks) {
if (mDragState == STATE_SETTLING) {
boolean keepGoing = mScroller.computeScrollOffset();
final int x = mScroller.getCurrX();
final int y = mScroller.getCurrY();
final int dx = x - mCapturedView.getLeft();
final int dy = y - mCapturedView.getTop();
if (dx != 0) {
ViewCompat.offsetLeftAndRight(mCapturedView, dx);
}
if (dy != 0) {
ViewCompat.offsetTopAndBottom(mCapturedView, dy);
}
if (dx != 0 || dy != 0) {
mCallback.onViewPositionChanged(mCapturedView, x, y, dx, dy);
}
if (keepGoing && x == mScroller.getFinalX() && y == mScroller.getFinalY()) {
// Close enough. The interpolator/scroller might think we're still moving
// but the user sure doesn't.
mScroller.abortAnimation();
keepGoing = false;
}
if (!keepGoing) {
if (deferCallbacks) {
mParentView.post(mSetIdleRunnable);
} else {
setDragState(STATE_IDLE);
}
}
}
return mDragState == STATE_SETTLING;
}
It simply animates the sheet up or down to desired position according the chosen target state.
Pseudo code of problem is:
launchAnimation(); // it takes eg 300 ms
changeVisibilityOfAnimatedViewChildren(); // this is problem
I can wait until the animation finishes, but as i said, in case of http request it is bit problem, i would like to ideally refresh the data right away without waiting.
Animated element is CoordinatorLayout. Affected child by setVisibility is one or more its children.
Judging by this link, android seems to have generally problem with animations and setVisibility.
Possible solutions i am thinking of now:
Maybe if i would change the visibility with another parallel postOnAnimation() task (?)
Or because it are basically just step by step subsequent calls of moving function mViewDragHelper.continueSettling() why don't do it without postOnAnimation()? I could run the task also without it. But i guess that postOnAnimation chooses some correct delay of animation step for concrete device + probably some other things.
You can add AnimatorListenerAdapter to your parent animation, and override onAnimationEnd() method. In this method you can call the child animation. However, I would rather change alpha of view than visibility. You can achieve more smoothly effect in this case.
For example, consider this code:
parentAnimationInstance.addListener(new AnimatorListenerAdapter() {
#Override
public void onAnimationEnd(Animator animation) {
super.onAnimationEnd(animation);
childView.animate()
.alpha(1.f)
.setDuration(200)
.start();
}
});
Iphone App video link
How I can design and develop view which is posted in above video? This is basically the item expansion of recyclerview with animation. I have tried with onItemtouchlistener of recyclerview and also with some custom view with animation, but didn't get the accurate result.
Finally i came accross addonscrolllistener, this give me results but not accurate.
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
if(newState == RecyclerView.FOCUS_UP) {
System.out.println("hello, ia m going up");
}
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if (dy > 0){
TextView tv = (TextView)recyclerView.findViewById(R.id.title);
//tv.setVisibility(View.VISIBLE);
if (tv.getVisibility()==View.VISIBLE){
System.out.println("yes");
}else {
slideToTop(tv);
}
}
}
});
private void slideToTop(View view){
TranslateAnimation animate = new TranslateAnimation(0,0,0,-view.getHeight());
animate.setDuration(1000);
animate.setFillAfter(false);
view.startAnimation(animate);
view.setVisibility(View.VISIBLE);
}
I think your question is too broad - however, here is some psuedocode:
onScrolled() {
View child = getSecondVisibleChild();
int distanceFromTop = child.getTop();
int distanceAtWhichExpandingShouldOccur = 100;
if(distanceFromTop < distanceAtWhichExpandingShouldOccur ) {
child.setHeight(child.getOriginalHeight() + (distanceFromTop - distanceAtWhichExpandingShouldOccur))
}
}
So you'll notice, the second visible child is the one who's height changes. It changed when it's less than distanceAtWhichExpandingShouldOccur from the top of the window. Its height changes to ensure its bottom remains stationary - therefore its height is increasing at the same pace its top is moving.
Once it's no longer the second visible child (aka, its top is 0), it should be scrolled off as normal and the next child should have its height changed when its top is less than distanceAtWhichExpandingShouldOccur.
This library can be a study case for you: https://github.com/florent37/MaterialLeanBack
This is my first ever post here and I'm a dumb novice, so I hope someone out there can both help me and excuse my ignorance.
I have a ListView which is populated with an ArrayAdapter. When I either scroll or click, I want the selected item, or the item nearest the vertical center, to be forced to the exact vertical center of the screen. If I call listView.setSelection(int position) it aligns the selected position at the top of the screen, so I need to use listView.setSelectionFromTop(position, offset) instead. To find my offset, I take half of the View's height from the half of the ListView's height.
So, I can vertically center my item easy enough, within OnItemClick or OnScrollStateChanged, with the following:
int x = listView.getHeight();
int y = listView.getChildAt(0).getHeight();
listView.setSelectionFromTop(myPosition, x/2 - y/2);
All this works fine. My problem is with the initial ListView setup. I want an item to be centered when the activity starts, but I can't because I get a NullPointerException from:
int y = listView.getChildAt(0).getHeight();
I understand this is because the ListView has not yet rendered, so it has no children, when I call this from OnCreate() or OnResume().
So my question is simply: how can I force my ListView to render at startup so I can get the height value I need? Or, alternatively, is there any other way to center items vertically within a ListView?
Thanks in advance for any help!
int y = listView.getChildAt(0).getHeight();
I understand this is because the ListView has not yet rendered, so it has no children, when I call this from onCreate() or onResume().
You should call it in onScroll.
listView.setOnScrollListener(new OnScrollListener() {
#Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}
#Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
//Write your logic here
int y = listView.getChildAt(0).getHeight();
}
});
I'm answering my own question here, but it's very much a hack. I think it's interesting because it sheds some light on the behavior of listviews.
The problem was in trying to act on data (a listview row) that did not yet exist (it had not been rendered). listview.getChildAt(int) was null because the listview had no children yet. I found out onScroll() is called immediately when the activity is created, so I simply put everything in a thread and delayed the getChildAt() call. I then enclosed the whole thing in a boolean wrapper to make sure it is only ever called once (on startup).
The interesting thing was that I only had to delay the call by 1ms for everything to be OK. And that's too fast for the eye to see.
Like I said, this is all a hack so I'm sure all this is a bad idea. Thanks for any help!
private boolean listViewReady = false;
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
if (!listViewReady){
Thread timer = new Thread() {
public void run() {
try{
sleep(1);
}catch (InterruptedException e) {
e.printStackTrace();
}finally{
runOnUiThread(new Runnable() {
public void run() {
myPosition = 2;
int x = listView.getHeight();
int y = listView.getChildAt(0).getHeight();
listView.setSelectionFromTop(myPosition, x/2 - y/2);
listViewReady = true;
}
});
}
}
};
timer.start();
}//if !ListViewReady
I have achieved the same using a in my opinion slighlty simpler solution
mListView.post(new Runnable() {
#Override
public void run() {
int height = mListView.getHeight();
int itemHeight = mListView.getChildAt(0).getHeight();
if (positionOfMyItem == myCollection.size() - 1) {
// last element - > don't subtract item height
itemHeight = 0;
}
mListView.setSelectionFromTop(position, height / 2 - itemHeight / 2);
}
});
I have a very long activity with a scrollview. It is a form with various fields that the user must fill in. I have a checkbox half way down my form, and when the user checks it I want to scroll to a specific part of the view. Is there any way to scroll to an EditText object (or any other view object) programmatically?
Also, I know this is possible using X and Y coords but I want to avoid doing this as the form may changed from user to user.
private final void focusOnView(){
yourScrollView.post(new Runnable() {
#Override
public void run() {
yourScrollView.scrollTo(0, yourEditText.getBottom());
}
});
}
The answer of Sherif elKhatib can be greatly improved, if you want to scroll the view to the center of the scroll view. This reusable method smooth scrolls the view to the visible center of a HorizontalScrollView.
private final void focusOnView(final HorizontalScrollView scroll, final View view) {
new Handler().post(new Runnable() {
#Override
public void run() {
int vLeft = view.getLeft();
int vRight = view.getRight();
int sWidth = scroll.getWidth();
scroll.smoothScrollTo(((vLeft + vRight - sWidth) / 2), 0);
}
});
}
For a vertical ScrollView use
...
int vTop = view.getTop();
int vBottom = view.getBottom();
int sHeight = scroll.getBottom();
scroll.smoothScrollTo(0, ((vTop + vBottom - sHeight) / 2));
...
This works well for me :
targetView.getParent().requestChildFocus(targetView,targetView);
public void RequestChildFocus (View child, View focused)
child - The child of this ViewParent that wants focus. This view will contain the focused view. It is not necessarily the view that actually has focus.
focused - The view that is a descendant of child that actually has focus
In my opinion the best way to scroll to a given rectangle is via View.requestRectangleOnScreen(Rect, Boolean). You should call it on a View you want to scroll to and pass a local rectangle you want to be visible on the screen. The second parameter should be false for smooth scrolling and true for immediate scrolling.
final Rect rect = new Rect(0, 0, view.getWidth(), view.getHeight());
view.requestRectangleOnScreen(rect, false);
I made a small utility method based on Answer from WarrenFaith, this code also takes in account if that view is already visible in the scrollview, no need for scroll.
public static void scrollToView(final ScrollView scrollView, final View view) {
// View needs a focus
view.requestFocus();
// Determine if scroll needs to happen
final Rect scrollBounds = new Rect();
scrollView.getHitRect(scrollBounds);
if (!view.getLocalVisibleRect(scrollBounds)) {
new Handler().post(new Runnable() {
#Override
public void run() {
scrollView.smoothScrollTo(0, view.getBottom());
}
});
}
}
You should make your TextView request focus:
mTextView.requestFocus();
Another varition would be:
scrollView.postDelayed(new Runnable()
{
#Override
public void run()
{
scrollView.smoothScrollTo(0, img_transparent.getTop());
}
}, 200);
or you can use the post() method.
My EditText was nested several layers inside my ScrollView, which itself isn't the layout's root view. Because getTop() and getBottom() were seeming to report the coordinates within it's containing view, I had it compute the distance from the top of the ScrollView to the top of the EditText by iterating through the parents of the EditText.
// Scroll the view so that the touched editText is near the top of the scroll view
new Thread(new Runnable()
{
#Override
public
void run ()
{
// Make it feel like a two step process
Utils.sleep(333);
// Determine where to set the scroll-to to by measuring the distance from the top of the scroll view
// to the control to focus on by summing the "top" position of each view in the hierarchy.
int yDistanceToControlsView = 0;
View parentView = (View) m_editTextControl.getParent();
while (true)
{
if (parentView.equals(scrollView))
{
break;
}
yDistanceToControlsView += parentView.getTop();
parentView = (View) parentView.getParent();
}
// Compute the final position value for the top and bottom of the control in the scroll view.
final int topInScrollView = yDistanceToControlsView + m_editTextControl.getTop();
final int bottomInScrollView = yDistanceToControlsView + m_editTextControl.getBottom();
// Post the scroll action to happen on the scrollView with the UI thread.
scrollView.post(new Runnable()
{
#Override
public void run()
{
int height =m_editTextControl.getHeight();
scrollView.smoothScrollTo(0, ((topInScrollView + bottomInScrollView) / 2) - height);
m_editTextControl.requestFocus();
}
});
}
}).start();
The above answers will work fine if the ScrollView is the direct parent of the ChildView. If your ChildView is being wrapped in another ViewGroup in the ScrollView, it will cause unexpected behavior because the View.getTop() get the position relative to its parent. In such case, you need to implement this:
public static void scrollToInvalidInputView(ScrollView scrollView, View view) {
int vTop = view.getTop();
while (!(view.getParent() instanceof ScrollView)) {
view = (View) view.getParent();
vTop += view.getTop();
}
final int scrollPosition = vTop;
new Handler().post(() -> scrollView.smoothScrollTo(0, scrollPosition));
}
I know this may be too late for a better answer but a desired perfect solution must be a system like positioner. I mean, when system makes a positioning for an Editor field it places the field just up to the keyboard, so as UI/UX rules it is perfect.
What below code makes is the Android way positioning smoothly. First of all we keep the current scroll point as a reference point. Second thing is to find the best positioning scroll point for an editor, to do this we scroll to top, and then request the editor fields to make the ScrollView component to do the best positioning. Gatcha! We've learned the best position. Now, what we'll do is scroll smoothly from the previous point to the point we've found newly. If you want you may omit smooth scrolling by using scrollTo instead of smoothScrollTo only.
NOTE: The main container ScrollView is a member field named scrollViewSignup, because my example was a signup screen, as you may figure out a lot.
view.setOnFocusChangeListener(new View.OnFocusChangeListener() {
#Override
public void onFocusChange(final View view, boolean b) {
if (b) {
scrollViewSignup.post(new Runnable() {
#Override
public void run() {
int scrollY = scrollViewSignup.getScrollY();
scrollViewSignup.scrollTo(0, 0);
final Rect rect = new Rect(0, 0, view.getWidth(), view.getHeight());
view.requestRectangleOnScreen(rect, true);
int new_scrollY = scrollViewSignup.getScrollY();
scrollViewSignup.scrollTo(0, scrollY);
scrollViewSignup.smoothScrollTo(0, new_scrollY);
}
});
}
}
});
If you want to use this block for all EditText instances, and quickly integrate it with your screen code. You can simply make a traverser like below. To do this, I've made the main OnFocusChangeListener a member field named focusChangeListenerToScrollEditor, and call it during onCreate as below.
traverseEditTextChildren(scrollViewSignup, focusChangeListenerToScrollEditor);
And the method implementation is as below.
private void traverseEditTextChildren(ViewGroup viewGroup, View.OnFocusChangeListener focusChangeListenerToScrollEditor) {
int childCount = viewGroup.getChildCount();
for (int i = 0; i < childCount; i++) {
View view = viewGroup.getChildAt(i);
if (view instanceof EditText)
{
((EditText) view).setOnFocusChangeListener(focusChangeListenerToScrollEditor);
}
else if (view instanceof ViewGroup)
{
traverseEditTextChildren((ViewGroup) view, focusChangeListenerToScrollEditor);
}
}
}
So, what we've done here is making all EditText instance children to call the listener at focus.
To reach this solution, I've checked it out all the solutions here, and generated a new solution for better UI/UX result.
Many thanks to all other answers inspiring me much.
yourScrollView.smoothScrollTo(0, yourEditText.getTop());
Just Do It ;)
scrollView.post(new Runnable() {
#Override
public void run() {
scrollView.smoothScrollTo(0, myTextView.getTop());
}
});
Answering from my practical project.
I think I have found more elegant and less error prone solution using
ScrollView.requestChildRectangleOnScreen
There is no math involved, and contrary to other proposed solutions, it will handle correctly scrolling both up and down.
/**
* Will scroll the {#code scrollView} to make {#code viewToScroll} visible
*
* #param scrollView parent of {#code scrollableContent}
* #param scrollableContent a child of {#code scrollView} whitch holds the scrollable content (fills the viewport).
* #param viewToScroll a child of {#code scrollableContent} to whitch will scroll the the {#code scrollView}
*/
void scrollToView(ScrollView scrollView, ViewGroup scrollableContent, View viewToScroll) {
Rect viewToScrollRect = new Rect(); //coordinates to scroll to
viewToScroll.getHitRect(viewToScrollRect); //fills viewToScrollRect with coordinates of viewToScroll relative to its parent (LinearLayout)
scrollView.requestChildRectangleOnScreen(scrollableContent, viewToScrollRect, false); //ScrollView will make sure, the given viewToScrollRect is visible
}
It is a good idea to wrap it into postDelayed to make it more reliable, in case the ScrollView is being changed at the moment
/**
* Will scroll the {#code scrollView} to make {#code viewToScroll} visible
*
* #param scrollView parent of {#code scrollableContent}
* #param scrollableContent a child of {#code scrollView} whitch holds the scrollable content (fills the viewport).
* #param viewToScroll a child of {#code scrollableContent} to whitch will scroll the the {#code scrollView}
*/
private void scrollToView(final ScrollView scrollView, final ViewGroup scrollableContent, final View viewToScroll) {
long delay = 100; //delay to let finish with possible modifications to ScrollView
scrollView.postDelayed(new Runnable() {
public void run() {
Rect viewToScrollRect = new Rect(); //coordinates to scroll to
viewToScroll.getHitRect(viewToScrollRect); //fills viewToScrollRect with coordinates of viewToScroll relative to its parent (LinearLayout)
scrollView.requestChildRectangleOnScreen(scrollableContent, viewToScrollRect, false); //ScrollView will make sure, the given viewToScrollRect is visible
}
}, delay);
}
reference : https://stackoverflow.com/a/6438240/2624806
Following worked far better.
mObservableScrollView.post(new Runnable() {
public void run() {
mObservableScrollView.fullScroll([View_FOCUS][1]);
}
});
Examining Android source code, you can find that there already is a member function of ScrollView– scrollToChild(View) – that does exactly what is requested. Unfortunatelly, this function is for some obscure reason marked private. Based on that function I've written following function that finds the first ScrollView above the View specified as a parameter and scrolls it so that it becomes visible within the ScrollView:
private void make_visible(View view)
{
int vt = view.getTop();
int vb = view.getBottom();
View v = view;
for(;;)
{
ViewParent vp = v.getParent();
if(vp == null || !(vp instanceof ViewGroup))
break;
ViewGroup parent = (ViewGroup)vp;
if(parent instanceof ScrollView)
{
ScrollView sv = (ScrollView)parent;
// Code based on ScrollView.computeScrollDeltaToGetChildRectOnScreen(Rect rect) (Android v5.1.1):
int height = sv.getHeight();
int screenTop = sv.getScrollY();
int screenBottom = screenTop + height;
int fadingEdge = sv.getVerticalFadingEdgeLength();
// leave room for top fading edge as long as rect isn't at very top
if(vt > 0)
screenTop += fadingEdge;
// leave room for bottom fading edge as long as rect isn't at very bottom
if(vb < sv.getChildAt(0).getHeight())
screenBottom -= fadingEdge;
int scrollYDelta = 0;
if(vb > screenBottom && vt > screenTop)
{
// need to move down to get it in view: move down just enough so
// that the entire rectangle is in view (or at least the first
// screen size chunk).
if(vb-vt > height) // just enough to get screen size chunk on
scrollYDelta += (vt - screenTop);
else // get entire rect at bottom of screen
scrollYDelta += (vb - screenBottom);
// make sure we aren't scrolling beyond the end of our content
int bottom = sv.getChildAt(0).getBottom();
int distanceToBottom = bottom - screenBottom;
scrollYDelta = Math.min(scrollYDelta, distanceToBottom);
}
else if(vt < screenTop && vb < screenBottom)
{
// need to move up to get it in view: move up just enough so that
// entire rectangle is in view (or at least the first screen
// size chunk of it).
if(vb-vt > height) // screen size chunk
scrollYDelta -= (screenBottom - vb);
else // entire rect at top
scrollYDelta -= (screenTop - vt);
// make sure we aren't scrolling any further than the top our content
scrollYDelta = Math.max(scrollYDelta, -sv.getScrollY());
}
sv.smoothScrollBy(0, scrollYDelta);
break;
}
// Transform coordinates to parent:
int dy = parent.getTop()-parent.getScrollY();
vt += dy;
vb += dy;
v = parent;
}
}
My solution is:
int[] spinnerLocation = {0,0};
spinner.getLocationOnScreen(spinnerLocation);
int[] scrollLocation = {0, 0};
scrollView.getLocationInWindow(scrollLocation);
int y = scrollView.getScrollY();
scrollView.smoothScrollTo(0, y + spinnerLocation[1] - scrollLocation[1]);
Vertical scroll, good for forms. Answer is based on Ahmadalibaloch horizontal scroll.
private final void focusOnView(final HorizontalScrollView scroll, final View view) {
new Handler().post(new Runnable() {
#Override
public void run() {
int top = view.getTop();
int bottom = view.getBottom();
int sHeight = scroll.getHeight();
scroll.smoothScrollTo(0, ((top + bottom - sHeight) / 2));
}
});
}
You can use ObjectAnimator like this:
ObjectAnimator.ofInt(yourScrollView, "scrollY", yourView.getTop()).setDuration(1500).start();
Add postDelayed to the view so that getTop() does not return 0.
binding.scrollViewLogin.postDelayed({
val scrollTo = binding.textInputLayoutFirstName.top
binding.scrollViewLogin.isSmoothScrollingEnabled = true
binding.scrollViewLogin.smoothScrollTo(0, scrollTo)
}, 400
)
Also make sure the view is a direct child of scrollView, otherwise you would get getTop() as zero. Example: getTop() of edittext which is embedded inside TextInputLayout would return 0. So in this case, we have to compute getTop() of TextInputLayout which is a direct child of ScrollView.
<ScrollView>
<TextInputLayout>
<EditText/>
</TextInputLayout>
</ScrollView>
In my case, that's not EditText, that's googleMap.
And it works successfully like this.
private final void focusCenterOnView(final ScrollView scroll, final View view) {
new Handler().post(new Runnable() {
#Override
public void run() {
int centreX=(int) (view.getX() + view.getWidth() / 2);
int centreY= (int) (view.getY() + view.getHeight() / 2);
scrollView.smoothScrollBy(centreX, centreY);
}
});
}
Que:Is there a way to programmatically scroll a scroll view to a specific edittext?
Ans:Nested scroll view in recyclerview last position added record data.
adapter.notifyDataSetChanged();
nested_scroll.setScrollY(more Detail Recycler.getBottom());
Is there a way to programmatically scroll a scroll view to a specific edit text?
The following is what I'm using:
int amountToScroll = viewToShow.getBottom() - scrollView.getHeight() + ((LinearLayout.LayoutParams) viewToShow.getLayoutParams()).bottomMargin;
// Check to see if scrolling is necessary to show the view
if (amountToScroll > 0){
scrollView.smoothScrollTo(0, amountToScroll);
}
This gets the scroll amount necessary to show the bottom of the view, including any margin on the bottom of that view.
Based on Sherif's answer, the following worked best for my use case. Notable changes are getTop() instead of getBottom() and smoothScrollTo() instead of scrollTo().
private void scrollToView(final View view){
final ScrollView scrollView = findViewById(R.id.bookmarksScrollView);
if(scrollView == null) return;
scrollView.post(new Runnable() {
#Override
public void run() {
scrollView.smoothScrollTo(0, view.getTop());
}
});
}
If you want to scroll to a view when a soft keyboard is opened, then it might get a bit tricky.
The best solution I've got so far is to use a combination of inset callbacks and requestRectangleOnScreen method.
First, you need to setup inset callbacks:
fun View.doOnApplyWindowInsetsInRoot(block: (View, WindowInsetsCompat, Rect) -> Unit) {
val initialPadding = recordInitialPaddingForView(this)
val root = getRootForView(this)
ViewCompat.setOnApplyWindowInsetsListener(root) { v, insets ->
block(v, insets, initialPadding)
insets
}
requestApplyInsetsWhenAttached()
}
fun View.requestApplyInsetsWhenAttached() {
if (isAttachedToWindow) {
requestApplyInsets()
} else {
addOnAttachStateChangeListener(object : View.OnAttachStateChangeListener {
override fun onViewAttachedToWindow(v: View) {
v.removeOnAttachStateChangeListener(this)
v.requestApplyInsets()
}
override fun onViewDetachedFromWindow(v: View) = Unit
})
}
}
We are setting a callback on a root view to make sure we get called. Insets could be consumed before our view in question received them, so we have to do additional work here.
Now it's almost easy:
doOnApplyWindowInsetsInRoot { _, _, _ ->
post {
if (viewInQuestion.hasFocus()) {
requestRectangleOnScreen(Rect(0, 0, width, height))
}
}
}
You can get rid of a focus check. It's there to limit number of calls to requestRectangleOnScreen. I use post to run an action after scrollable parent scheduled scroll to a focused view.
If anybody is looking for a Kotlin version you can do this with an extension function
fun ScrollView.scrollToChild(view: View, onScrolled: (() -> Unit)? = null) {
view.requestFocus()
val scrollBounds = Rect()
getHitRect(scrollBounds)
if (!view.getLocalVisibleRect(scrollBounds)) {
findViewTreeLifecycleOwner()?.lifecycleScope?.launch(Dispatchers.Main) {
smoothScrollTo(0, view.bottom - 40)
onScrolled?.invoke()
}
}
}
There is a little callback that lets you do something after the scroll.
If scrlMain is your NestedScrollView, then use the following:
scrlMain.post(new Runnable() {
#Override
public void run() {
scrlMain.fullScroll(View.FOCUS_UP);
}
});
here is another better version for efficient scrolling:
kotlin code to scroll to particular position of view added in scrollview(horizontal)
horizontalScrollView.post {
val targetView = findViewById<View>(R.id.target_view)
val targetX = targetView.left
horizontalScrollView.smoothScrollTo(targetX, 0)
}
for vertical scroll just change targetView.left to targetView.top
for JAVA here is a sample code:
scrollView.postDelayed(new Runnable() {
#Override
public void run() {
int targetViewY = targetView.getTop();
scrollView.smoothScrollTo(0, targetViewY);
}
}, 500);