I have a RecyclerView that contains a list of cards, each of which expand into child cards.
Each card has different text. I want that when the user clicks on a child card, it will expand to show the text inside. The expansion height is based on how much text the card contains.
I tried to measure the target height by using:
view.Measure(ViewGroup.LayoutParams.WrapContent, ViewGroup.LayoutParams.WrapContent);
And then expanding the card to the Measured Height (see here).
However, it gives the same Measured Height to all of the cards.
Here is my code, which is based on this (more specifically the Xamarin version):
This is the main Adapter, which creates and binds the parent and the child cards:
public class HalachaExpandableAdapter : ExpandableRecyclerAdapter<HalachaParentViewHolder, HalachaChildViewHolder>, View.IOnClickListener
{
LayoutInflater _inflater;
bool expand;
int targetHeight;
bool wave = false;
public HalachaExpandableAdapter(Context context, List<IParentObject> itemList) : base(context, itemList)
{
_inflater = LayoutInflater.From(context);
}
public override void OnBindChildViewHolder(HalachaChildViewHolder childViewHolder, int position, object childObject)
{
var halachaChild = (HalachaChild)childObject;
childViewHolder.halachaChildTitle.Text = halachaChild.Title.ToString();
targetHeight = childViewHolder.halachaChildCard.Height;
childViewHolder.halachaChildCard.LayoutParameters.Height = 100;
childViewHolder.halachaChildCard.SetOnClickListener(this);
expand = childViewHolder.expand;
}
public override void OnBindParentViewHolder(HalachaParentViewHolder parentViewHolder, int position, object parentObject)
{
var halacha = (HalachaItem)parentObject;
parentViewHolder._halachaTitleTextView.Text = halacha.Title();
parentViewHolder._halachaContentTextView.Text = halacha.Content;
if (halacha.ChildObjectList.Count == 1)
wave = true;
}
public void OnClick(View v)
{
if (v.Height == 100)
{
AnimationCollapse anim = new AnimationCollapse(v, targetHeight, 100);
anim.Duration = 300;
v.StartAnimation(anim);
expand = false;
}
else
{
AnimationCollapse anim = new AnimationCollapse(v, 100, v.Height);
anim.Duration = 300;
v.StartAnimation(anim);
expand = true;
}
}
public override HalachaChildViewHolder OnCreateChildViewHolder(ViewGroup childViewGroup)
{
var view = _inflater.Inflate(Resource.Layout.halachotListItem, childViewGroup, false);
return new HalachaChildViewHolder(view);
}
public override HalachaParentViewHolder OnCreateParentViewHolder(ViewGroup parentViewGroup)
{
var view = _inflater.Inflate(Resource.Layout.halachotListHeader, parentViewGroup, false);
wave = false;
return new HalachaParentViewHolder(view);
}
}
I think this is where the code is needed to be done, but if you need some of the other code of the other classes, I will gladly post them. You can also look at the links above for reference to how this works.
Hope someone can help me.
Thanks!
I finally managed to solve the problem.
I needed to change the way I measured the view's wrap_content height to this:
v.Measure(MeasureSpec.MakeMeasureSpec(v.Width, MeasureSpecMode.Exactly), MeasureSpec.MakeMeasureSpec(ViewGroup.LayoutParams.WrapContent, MeasureSpecMode.AtMost));
The rest is the same.
Thanks to this post.
I dont know why do you want to find the height of the card , instead you can just wrap the child cards height to that of text and make child card invisible , as soon as user click a card , child card s visiblity will be turned to visible and card wih its text with the same height will appear !
What i've tried to far:
Calling measure()
tv.measure(0, 0);
int height = tv.getMeasuredHeight();
Calling measure() with specified sizes/modes
int widthMeasureSpec = View.MeasureSpec.makeMeasureSpec(99999, View.MeasureSpec.AT_MOST);
int heightMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
tv.measure(widthMeasureSpec, heightMeasureSpec);
int height = tv.getMeasuredHeight();
Calling getTextBounds()
Rect bounds = new Rect();
tv.getPaint().getTextBounds(tv.getText().toString(), 0, tv.getText().length(), bounds);
int height = bounds.height();
Calling measure() and then calling getTextBounds()
Calling getLineCount() * getLineHeight()
None seem to work. They all return incorrect values (container view gets incorrect height - it's either too small or too large)
Ideas on how to calculate this simple thing??
You need to specify the available width so the height can be properly calculated.
Note: In cases where you just need to get the height of a view that is already drawn, use ViewTreeObserver. See this question for a thing to consider in that case.
This is why I do, in a piece of code where I want to scale a view from hidden to its full necessary height:
int availableWidth = getParentWidth(viewToScale);
int widthSpec = View.MeasureSpec.makeMeasureSpec(availableWidth, View.MeasureSpec.AT_MOST);
int heightSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
viewToScale.measure(widthSpec, heightSpec);
int measuredHeight = viewToScale.getMeasuredHeight();
// Offtopic: Now I animate the height from 1 to measuredHeight (0 doesn't work)
You may pass the availableWidth yourself, but I calculate it from the parent:
private int getParentWidth(View viewToScale)
{
final ViewParent parent = viewToScale.getParent();
if (parent instanceof View) {
final int parentWidth = ((View) parent).getWidth();
if (parentWidth > 0) {
return parentWidth;
}
}
throw new IllegalStateException("View to scale must have parent with measured width");
}
Where are you calling those methods?
The best way to do what you are trying to do is to use ViewTreeObserver and add onPreDrawListener.
Take a look at this i think it will help
What you can do here is get ViewTreeObserver associated with this TextView and add OnGlobalLayoutListener to it:
final ViewTreeObserver vto = textView.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
// textView dimensions are calculated at this stage, but textView
// isn't rendered yet. Do what you need to do and remove OnGlobalLayoutListener
// after
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
textView.getViewTreeObserver().removeGlobalOnLayoutListener(this);
} else {
textView.getViewTreeObserver().removeOnGlobalLayoutListener(this);
}
}
}
I had a similar problem recently, trying to measure the height of a ViewGroup containing several multiline TextView.
What worked for me was to measure() the TextView, then add (lineCount-1)*lineHeight to its measuredHeight.
Here is the code to measure only one TextView :
private int getMeasuredHeight(TextView textView) {
textView.measure(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
int height = textView.getMeasuredHeight();
height += (textView.getLineCount()-1) * textView.getLineHeight();
return height;
}
And in the case of a ViewGroup with many TextViews, here is my code :
private int getMeasuredHeight(ViewGroup viewGroup) {
viewGroup.measure(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
int height = viewGroup.getMeasuredHeight();
for(TextView textView : findAllTextView(viewGroup)) {
height += (textView.getLineCount()-1) * textView.getLineHeight();
}
return height;
}
private List<TextView> findAllTextView(ViewGroup v) {
List<TextView> result = new ArrayList<>();
for (int i = 0; i < v.getChildCount(); i++) {
Object child = v.getChildAt(i);
if (child instanceof TextView)
result.add((TextView) child);
else if (child instanceof ViewGroup)
for(TextView tv: findAllTextView((ViewGroup) child))
result.add(tv);
}
return result;
}
I have a RecyclerView with Expandable Child Views, when the child ViewGroup is clicked it inflates an amount of views animating the ViewGroup height from 0 to the measured viewgroup height, like the following gif:
The problem is: I'm calling smoothScrollToPosition on recyclerView, it smooth scroll to the view position, but it considers the current view height, which is still not expanded, in the above gif i'm touching on the under view of the recyclerview, which dont scroll to position because the view is already visible, but when i touch again (calling the smoothscrolltoposition again) it scroll the view to the correct position, because the view is already expanded.
Is there any approach to scroll the view to the top of screen or just scroll to make content visible?
For references:
This is the method called to inflate the views:
collapsible_content.removeAllViews();
for(int i = 0; i < 5; i++) {
View link_view = getLayoutInflater().inflate(R.layout.list_item_timeline_step_link, collapsible_content, false);
TextView text = (TextView) link_view.findViewById(R.id.step_link_text);
text.setText("Test");
collapsible_content.addView(link_view);
}
And this is my method to expand:
public void toggle() {
collapsible_content.measure(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
Animation a;
if (mExpanded) {
a = new ExpandAnimation(collapsible_content.getLayoutParams().height, 0);
} else {
a = new ExpandAnimation(collapsible_content.getLayoutParams().height, getMeasuredHeight());
}
a.setDuration(mAnimationDuration);
collapsible_content.startAnimation(a);
mExpanded = !mExpanded;
}
And the animation:
private class ExpandAnimation extends Animation {
private final int mStartHeight;
private final int mDeltaHeight;
public ExpandAnimation(int startHeight, int endHeight) {
mStartHeight = startHeight;
mDeltaHeight = endHeight - startHeight;
}
#Override
protected void applyTransformation(float interpolatedTime,
Transformation t) {
final int newHeight = (int) (mStartHeight + mDeltaHeight *
interpolatedTime);
collapsible_content getLayoutParams().height = newHeight;
if (newHeight <= 0) {
collapsible_content setVisibility(View.GONE);
} else {
collapsible_content setVisibility(View.VISIBLE);
}
collapsible_content requestLayout();
}
#Override
public boolean willChangeBounds() {
return true;
}
}
My solution was to constant check for view bottom within applyTransformation method, and compare it with RecyclerView height, if the bottom get higher than the RV height, i scroll by the diff values:
final int bottom = collapsible_content.getBottom();
final int listViewHeight = mRecyclerView.getHeight();
if (bottom > listViewHeight) {
final int top = collapsible_content.getTop();
if (top > 0) {
mRecyclerView.smoothScrollBy(0, Math.min(bottom - listViewHeight + mRecyclerView.getPaddingBottom(), top));
}
}
The trick was to use Math.min to get the view top, so it don't scroll up making the top not visible.
Solution based on ListViewAnimations
Add an animationlistener and start the scrolling of the recyclerview after the expanding animation is finished.
I am creating all of the elements in my android project dynamically. I am trying to get the width and height of a button so that I can rotate that button around. I am just trying to learn how to work with the android language. However, it returns 0.
I did some research and I saw that it needs to be done somewhere other than in the onCreate() method. If someone can give me an example of how to do it, that would be great.
Here is my current code:
package com.animation;
import android.app.Activity;
import android.os.Bundle;
import android.view.animation.Animation;
import android.view.animation.LinearInterpolator;
import android.view.animation.RotateAnimation;
import android.widget.Button;
import android.widget.LinearLayout;
public class AnimateScreen extends Activity {
//Called when the activity is first created.
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
LinearLayout ll = new LinearLayout(this);
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
layoutParams.setMargins(30, 20, 30, 0);
Button bt = new Button(this);
bt.setText(String.valueOf(bt.getWidth()));
RotateAnimation ra = new RotateAnimation(0,360,bt.getWidth() / 2,bt.getHeight() / 2);
ra.setDuration(3000L);
ra.setRepeatMode(Animation.RESTART);
ra.setRepeatCount(Animation.INFINITE);
ra.setInterpolator(new LinearInterpolator());
bt.startAnimation(ra);
ll.addView(bt,layoutParams);
setContentView(ll);
}
Any help is appreciated.
The basic problem is, that you have to wait for the drawing phase for the actual measurements (especially with dynamic values like wrap_content or match_parent), but usually this phase hasn't been finished up to onResume(). So you need a workaround for waiting for this phase. There a are different possible solutions to this:
1. Listen to Draw/Layout Events: ViewTreeObserver
A ViewTreeObserver gets fired for different drawing events. Usually the OnGlobalLayoutListener is what you want for getting the measurement, so the code in the listener will be called after the layout phase, so the measurements are ready:
view.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
view.getViewTreeObserver().removeOnGlobalLayoutListener(this);
view.getHeight(); //height is ready
}
});
Note: The listener will be immediately removed because otherwise it will fire on every layout event. If you have to support apps SDK Lvl < 16 use this to unregister the listener:
public void removeGlobalOnLayoutListener (ViewTreeObserver.OnGlobalLayoutListener victim)
2. Add a runnable to the layout queue: View.post()
Not very well known and my favourite solution. Basically just use the View's post method with your own runnable. This basically queues your code after the view's measure, layout, etc. as stated by Romain Guy:
The UI event queue will process events in order. After
setContentView() is invoked, the event queue will contain a message
asking for a relayout, so anything you post to the queue will happen
after the layout pass
Example:
final View view=//smth;
...
view.post(new Runnable() {
#Override
public void run() {
view.getHeight(); //height is ready
}
});
The advantage over ViewTreeObserver:
your code is only executed once and you don't have to disable the Observer after execution which can be a hassle
less verbose syntax
References:
https://stackoverflow.com/a/3602144/774398
https://stackoverflow.com/a/3948036/774398
3. Overwrite Views's onLayout Method
This is only practical in certain situation when the logic can be encapsulated in the view itself, otherwise this is a quite verbose and cumbersome syntax.
view = new View(this) {
#Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
super.onLayout(changed, l, t, r, b);
view.getHeight(); //height is ready
}
};
Also mind, that onLayout will be called many times, so be considerate what you do in the method, or disable your code after the first time
4. Check if has been through layout phase
If you have code that is executing multiple times while creating the ui you could use the following support v4 lib method:
View viewYouNeedHeightFrom = ...
...
if(ViewCompat.isLaidOut(viewYouNeedHeightFrom)) {
viewYouNeedHeightFrom.getHeight();
}
Returns true if view has been through at least one layout since it was
last attached to or detached from a window.
Additional: Getting staticly defined measurements
If it suffices to just get the statically defined height/width, you can just do this with:
View.getMeasuredWidth()
View.getMeasuredHeigth()
But mind you, that this might be different to the actual width/height after drawing. The javadoc describes the difference in more detail:
The size of a view is expressed with a width and a height. A view
actually possess two pairs of width and height values.
The first pair is known as measured width and measured height. These
dimensions define how big a view wants to be within its parent (see
Layout for more details.) The measured dimensions can be obtained by
calling getMeasuredWidth() and getMeasuredHeight().
The second pair is simply known as width and height, or sometimes
drawing width and drawing height. These dimensions define the actual
size of the view on screen, at drawing time and after layout. These
values may, but do not have to, be different from the measured width
and height. The width and height can be obtained by calling getWidth()
and getHeight().
We can use
#Override
public void onWindowFocusChanged(boolean hasFocus) {
super.onWindowFocusChanged(hasFocus);
//Here you can get the size!
}
You are calling getWidth() too early. The UI has not been sized and laid out on the screen yet.
I doubt you want to be doing what you are doing, anyway -- widgets being animated do not change their clickable areas, and so the button will still respond to clicks in the original orientation regardless of how it has rotated.
That being said, you can use a dimension resource to define the button size, then reference that dimension resource from your layout file and your source code, to avoid this problem.
I used this solution, which I think is better than onWindowFocusChanged(). If you open a DialogFragment, then rotate the phone, onWindowFocusChanged will be called only when the user closes the dialog):
yourView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
// Ensure you call it only once :
yourView.getViewTreeObserver().removeGlobalOnLayoutListener(this);
// Here you can get the size :)
}
});
Edit : as removeGlobalOnLayoutListener is deprecated, you should now do :
#SuppressLint("NewApi")
#SuppressWarnings("deprecation")
#Override
public void onGlobalLayout() {
// Ensure you call it only once :
if(android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.JELLY_BEAN) {
yourView.getViewTreeObserver().removeOnGlobalLayoutListener(this);
}
else {
yourView.getViewTreeObserver().removeGlobalOnLayoutListener(this);
}
// Here you can get the size :)
}
If you need to get width of some widget before it is displayed on screen, you can use getMeasuredWidth() or getMeasuredHeight().
myImage.measure(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
int width = myImage.getMeasuredWidth();
int height = myImage.getMeasuredHeight();
As Ian states in this Android Developers thread:
Anyhow, the deal is that layout of the
contents of a window happens
after all the elements are constructed and added to their parent
views. It has to be this way, because
until you know what components a View
contains, and what they contain, and
so on, there's no sensible way you can
lay it out.
Bottom line, if you call getWidth()
etc. in a constructor, it will return
zero. The procedure is to create all
your view elements in the constructor,
then wait for your View's
onSizeChanged() method to be called --
that's when you first find out your
real size, so that's when you set up
the sizes of your GUI elements.
Be aware too that onSizeChanged() is
sometimes called with parameters of
zero -- check for this case, and
return immediately (so you don't get a
divide by zero when calculating your
layout, etc.). Some time later it
will be called with the real values.
I would rather use OnPreDrawListener() instead of addOnGlobalLayoutListener(), since it is called a bit earlier than other listeners.
view.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener()
{
#Override
public boolean onPreDraw()
{
if (view.getViewTreeObserver().isAlive())
view.getViewTreeObserver().removeOnPreDrawListener(this);
// put your code here
return true;
}
});
Adjusted the code according to comment of #Pang. onPreDraw method should return true to proceed with the current drawing pass.
AndroidX has multiple extension functions that help you with this kind of work, inside androidx.core.view
You need to use Kotlin for this.
The one that best fits here is doOnLayout:
Performs the given action when this view is laid out. If the view has been laid out and it has not requested a layout, the action will be performed straight away otherwise, the action will be performed after the view is next laid out.
The action will only be invoked once on the next layout and then removed.
In your example:
bt.doOnLayout {
val ra = RotateAnimation(0,360,it.width / 2,it.height / 2)
// more code
}
Dependency: androidx.core:core-ktx:1.0.0
A Kotlin Extension to observe on the global layout and perform a given task when height is ready dynamically.
Usage:
view.height { Log.i("Info", "Here is your height:" + it) }
Implementation:
fun <T : View> T.height(function: (Int) -> Unit) {
if (height == 0)
viewTreeObserver.addOnGlobalLayoutListener(object : ViewTreeObserver.OnGlobalLayoutListener {
override fun onGlobalLayout() {
viewTreeObserver.removeOnGlobalLayoutListener(this)
function(height)
}
})
else function(height)
}
It happens because the view needs more time to be inflated. So instead of calling view.width and view.height on the main thread, you should use view.post { ... } to make sure that your view has already been inflated. In Kotlin:
view.post{width}
view.post{height}
In Java you can also call getWidth() and getHeight() methods in a Runnable and pass the Runnable to view.post() method.
view.post(new Runnable() {
#Override
public void run() {
view.getWidth();
view.getHeight();
}
});
One liner if you are using RxJava & RxBindings. Similar approach without the boilerplate. This also solves the hack to suppress warnings as in the answer by Tim Autin.
RxView.layoutChanges(yourView).take(1)
.subscribe(aVoid -> {
// width and height have been calculated here
});
This is it. No need to be unsubscribe, even if never called.
Maybe this helps someone:
Create an extension function for the View class
filename: ViewExt.kt
fun View.afterLayout(what: () -> Unit) {
if(isLaidOut) {
what.invoke()
} else {
viewTreeObserver.addOnGlobalLayoutListener(object : ViewTreeObserver.OnGlobalLayoutListener {
override fun onGlobalLayout() {
viewTreeObserver.removeOnGlobalLayoutListener(this)
what.invoke()
}
})
}
}
This can then be used on any view with:
view.afterLayout {
do something with view.height
}
Height and width are zero because view has not been created by the time you are requesting it's height and width .
One simplest solution is
view.post(new Runnable() {
#Override
public void run() {
view.getHeight(); //height is ready
view.getWidth(); //width is ready
}
});
This method is good as compared to other methods as it is short and crisp.
If you are using Kotlin
customView.viewTreeObserver.addOnGlobalLayoutListener(object : ViewTreeObserver.OnGlobalLayoutListener {
override fun onGlobalLayout() {
if(android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.JELLY_BEAN) {
customView.viewTreeObserver.removeOnGlobalLayoutListener(this)
}
else {
customView.viewTreeObserver.removeGlobalOnLayoutListener(this)
}
// Here you can get the size :)
viewWidth = customView.width
}
})
Answer with post is incorrect, because the size might not be recalculated.
Another important thing is that the view and all it ancestors must be visible. For that I use a property View.isShown.
Here is my kotlin function, that can be placed somewhere in utils:
fun View.onInitialized(onInit: () -> Unit) {
viewTreeObserver.addOnGlobalLayoutListener(object : OnGlobalLayoutListener {
override fun onGlobalLayout() {
if (isShown) {
viewTreeObserver.removeOnGlobalLayoutListener(this)
onInit()
}
}
})
}
And the usage is:
myView.onInitialized {
Log.d(TAG, "width is: " + myView.width)
}
For Kotlin:
I have faced a production crash due to use view.height/ view.width which lead to NaN while I was using View.post() which sometimes view diemsions returned with 0 value.
So,
Use view.doOnPreDraw { // your action here} which is:
OneShotPreDrawListener so it called only one time.
Implements OnPreDrawListener which make sure view is layouted and measured
well , you can use addOnLayoutChangeListener
you can use it in onCreate in Activity or onCreateView in Fragment
#Edit
dont forget to remove it because in some cases its trigger infinite loop
myView.addOnLayoutChangeListener(object : View.OnLayoutChangeListener{
override fun onLayoutChange(
v: View?, left: Int, top: Int, right: Int, bottom: Int, oldLeft: Int, oldTop: Int, oldRight: Int, oldBottom: Int
) {
if (v?.width > 0 && v?.height > 0){
// do something
Log.i(TAG, "view : ${view.width}")
// remove after finish
v?.removeOnLayoutChangeListener(this)
}
}
})
Cleanest way of doing this is using post method of view :
kotlin:
view.post{
var width = view.width
var height = view.height
}
Java:
view.post(new Runnable() {
#Override
public void run() {
int width = view.getWidth();
int height = view.getHeight();
}
});
Gone views returns 0 as height if app in background.
This my code (1oo% works)
fun View.postWithTreeObserver(postJob: (View, Int, Int) -> Unit) {
viewTreeObserver.addOnGlobalLayoutListener(object : ViewTreeObserver.OnGlobalLayoutListener {
override fun onGlobalLayout() {
val widthSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED)
val heightSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED)
measure(widthSpec, heightSpec)
postJob(this#postWithTreeObserver, measuredWidth, measuredHeight)
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
#Suppress("DEPRECATION")
viewTreeObserver.removeGlobalOnLayoutListener(this)
} else {
viewTreeObserver.removeOnGlobalLayoutListener(this)
}
}
})
}
We need to wait for view will be drawn. For this purpose use OnPreDrawListener. Kotlin example:
val preDrawListener = object : ViewTreeObserver.OnPreDrawListener {
override fun onPreDraw(): Boolean {
view.viewTreeObserver.removeOnPreDrawListener(this)
// code which requires view size parameters
return true
}
}
view.viewTreeObserver.addOnPreDrawListener(preDrawListener)
In my case, I can't get a view's height by post or by addOnGlobalLayoutListener, it's always 0. Because my view is in a fragment, and the fragment is the second tab in MainActivity. when I open MainActivity, I enter the first tab, so the second tab doesn't show on the screen. But onGlobalLayout() or post() function still has a callback.
I get the view's height when the second fragment is visible on the screen. And this time I get the correct height.
Usage:
imageView.size { width, height ->
//your code
}
View extention:
fun <T : View> T.size(function: (Int, Int) -> Unit) {
if (isLaidOut && height != 0 && width != 0) {
function(width, height)
} else {
if (height == 0 || width == 0) {
var onLayoutChangeListener: View.OnLayoutChangeListener? = null
var onGlobalLayoutListener: ViewTreeObserver.OnGlobalLayoutListener? = null
onGlobalLayoutListener = object : ViewTreeObserver.OnGlobalLayoutListener {
override fun onGlobalLayout() {
if (isShown) {
removeOnLayoutChangeListener(onLayoutChangeListener)
viewTreeObserver.removeOnGlobalLayoutListener(this)
function(width, height)
}
}
}
onLayoutChangeListener = object : View.OnLayoutChangeListener {
override fun onLayoutChange(
v: View?,
left: Int,
top: Int,
right: Int,
bottom: Int,
oldLeft: Int,
oldTop: Int,
oldRight: Int,
oldBottom: Int
) {
val width = v?.width ?: 0
val height = v?.height ?: 0
if (width > 0 && height > 0) {
// remove after finish
viewTreeObserver.removeOnGlobalLayoutListener(onGlobalLayoutListener)
v?.removeOnLayoutChangeListener(this)
function(width, height)
}
}
}
viewTreeObserver.addOnGlobalLayoutListener(onGlobalLayoutListener)
addOnLayoutChangeListener(onLayoutChangeListener)
} else {
function(width, height)
}
}
}
public final class ViewUtils {
public interface ViewUtilsListener {
void onDrawCompleted();
}
private ViewUtils() {
}
public static void onDraw(View view, ViewUtilsListener listener) {
view.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
if (view.getHeight() != 0 && view.getWidth() != 0) {
if (listener != null) {
listener.onDrawCompleted();
}
view.getViewTreeObserver().removeOnGlobalLayoutListener(this);
}
}
});
}
}
you can use like this ;
ViewUtils.onDraw(view, new ViewUtils.ViewUtilsListener() {
#Override
public void onDrawCompleted() {
int width = view.getWidth();
int height = view.getHeight();
}
});
private val getWidth: Int
get() {
if (Build.VERSION.SDK_INT >= 30) {
val windowMetrics =windowManager.currentWindowMetrics
val bounds = windowMetrics.bounds
var adWidthPixels = View.width.toFloat()
if (adWidthPixels == 0f) {
adWidthPixels = bounds.width().toFloat()
}
val density = resources.displayMetrics.density
val adWidth = (adWidthPixels / density).toInt()
return adWidth
} else {
val display = windowManager.defaultDisplay
val outMetrics = DisplayMetrics()
display.getMetrics(outMetrics)
val density = outMetrics.density
var adWidthPixels = View.width.toFloat()
if (adWidthPixels == 0f) {
adWidthPixels = outMetrics.widthPixels.toFloat()
}
val adWidth = (adWidthPixels / density).toInt()
return adWidth
}
}
replace (View) with the view you want to measure
This is a little old, but was having trouble with this myself (needing to animate objects in a fragment when it is created). This solution worked for me, I believe it is self explanatory.
class YourFragment: Fragment() {
var width = 0
var height = 0
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
val root = inflater.inflate(R.layout.fragment_winner_splash, container, false)
container?.width.let {
if (it != null) {
width = it
}
}
container?.height.let {
if (it != null) {
height = it
}
}
return root
}
If you're worried about overworking the onDraw method, you can always set the dimension as null during construction and then only set the dimension inside of onDraw if it's null.
That way you're not really doing any work inside onDraw
class myView(context:Context,attr:AttributeSet?):View(context,attr){
var height:Float?=null
override fun onDraw(canvas:Canvas){
if (height==null){height=this.height.toFloat()}
}
}