Overview: I'm trying to make a class which extends Drawable. My test app does not behave as I expect. No image fills the screen, when I expect one should.
Details: I am trying to understand how to create custom Drawables that take other Drawables as parameters and manipulate them as desired. I've read through and generally understand the source code for obvious existing examples such as LayerDrawable and LevelListDrawable, then I came across a very stripped back version of this concept in the ProxyDrawable class.
As I understand it, it basically;
overrides Drawable's getters to take the properties of the Drawable passed to its constructor as its own.
overrides Drawable's setters to pass on properties down to the passed in Drawable.
calls the passed in Drawable's own draw() method to draw it to the ProxyDrawable's canvas.
I have tried to implement this in a simple test app, as shown in the code below.
The FrameLayout frame1 is set to match_parent for both the width and height in my activity_main.xml so it takes up the full screen.
When I run this test app however, the ic_launcher image does not appear in the frame.
As noted in the code comments, if I use the ic_launcher directly when setting the frame's background, the image does appear. Hence the problem must be in the MyProxyDrawable class.
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
MyProxyDrawable myDrawable = new MyProxyDrawable(getResources().getDrawable(R.drawable.ic_launcher));
FrameLayout myFrame = (FrameLayout)findViewById(R.id.frame1);
myFrame.setBackground(myDrawable);
// ** NOTE **
// The ic_launcher image fills the whole screen if
// I replace the line above with the line below, so there
// is no problem with the resource or frame.
//myFrame.setBackground(getResources().getDrawable(R.drawable.ic_launcher));
}
public class MyProxyDrawable extends Drawable {
private Drawable mProxy;
private boolean mMutated;
public MyProxyDrawable(Drawable target) {
mProxy = target;
}
public Drawable getProxy() {
return mProxy;
}
public void setProxy(Drawable proxy) {
if (proxy != this) {
mProxy = proxy;
}
}
#Override
public void draw(Canvas canvas) {
if (mProxy != null) {
mProxy.draw(canvas);
}
}
#Override
public int getIntrinsicWidth() {
return mProxy != null ? mProxy.getIntrinsicWidth() : -1;
}
#Override
public int getIntrinsicHeight() {
return mProxy != null ? mProxy.getIntrinsicHeight() : -1;
}
#Override
public int getOpacity() {
return mProxy != null ? mProxy.getOpacity() : PixelFormat.TRANSPARENT;
}
#Override
public void setFilterBitmap(boolean filter) {
if (mProxy != null) {
mProxy.setFilterBitmap(filter);
}
}
#Override
public void setDither(boolean dither) {
if (mProxy != null) {
mProxy.setDither(dither);
}
}
#Override
public void setColorFilter(ColorFilter colorFilter) {
if (mProxy != null) {
mProxy.setColorFilter(colorFilter);
}
}
#Override
public void setAlpha(int alpha) {
if (mProxy != null) {
mProxy.setAlpha(alpha);
}
}
#Override
public Drawable mutate() {
if (mProxy != null && !mMutated && super.mutate() == this) {
mProxy.mutate();
mMutated = true;
}
return this;
}
}
}
Related
To begin with I have tried a lot of ways to make a smooth animation in Android and probably my best option was to use AnimationDrawable. Everything was perfect until I got out of memory exception on older devices. The reason for that obviously is the number of frames, in my case 75. That is how I got to the point of using AsyncTask and Thread.sleep() to animate the frames. To avoid animation lag I used a Stack in which I preload the first 10 frames and then just pop the used one and push a new one until there are no more frames. Everything worked better than I expected, but the only problem is that at the end of the animation the last frame disappears and I am hitting my head whole day to understand why is that happening with no success obviously. Below is the code from the Activity in which I call the animation and the file where the animation code is.
SplashActivity.java
private void startAnimation() {
gifImageView = (LogoAnimImageView) findViewById(R.id.gifImageView);
gifImageView.setSplashActivityContext(this);
gifImageView.setBackgroundResource(R.drawable.logo_frame_0);
gifImageView.setAnimImageViewListener(new LogoAnimImageView.LogoAnimImageViewInterface() {
#Override
public void animationEnd() {
mAnimationFinished = true;
LoadNextActivity();
}
});
gifImageView.startLogoAnimation();
}
LogoAnimImageView.java
public class LogoAnimImageView extends ImageView {
public interface LogoAnimImageViewInterface {
void animationEnd();
}
final Handler mHandler = new Handler();
private Stack<Drawable> mImageStack;
private SplashActivity mSplashActivity;
private LogoAnimImageViewInterface mListener;
private int mFrameIndex;
private int[] mResources = {R.drawable.logo_frame_0,R.drawable.logo_frame_1,R.drawable.logo_frame_2,R.drawable.logo_frame_3,
R.drawable.logo_frame_4,R.drawable.logo_frame_5,R.drawable.logo_frame_6,
R.drawable.logo_frame_7,R.drawable.logo_frame_8,R.drawable.logo_frame_9,R.drawable.logo_frame_10,
R.drawable.logo_frame_11,R.drawable.logo_frame_12,R.drawable.logo_frame_13,R.drawable.logo_frame_14,
R.drawable.logo_frame_15,R.drawable.logo_frame_16,R.drawable.logo_frame_17,R.drawable.logo_frame_18,
R.drawable.logo_frame_19,R.drawable.logo_frame_20,R.drawable.logo_frame_21,R.drawable.logo_frame_22,
R.drawable.logo_frame_23,R.drawable.logo_frame_24,R.drawable.logo_frame_25,R.drawable.logo_frame_26,
R.drawable.logo_frame_27,R.drawable.logo_frame_28,R.drawable.logo_frame_29,R.drawable.logo_frame_30,
R.drawable.logo_frame_31,R.drawable.logo_frame_32,R.drawable.logo_frame_33,R.drawable.logo_frame_34,
R.drawable.logo_frame_35,R.drawable.logo_frame_36,R.drawable.logo_frame_37,R.drawable.logo_frame_38,
R.drawable.logo_frame_39,R.drawable.logo_frame_40,R.drawable.logo_frame_41,R.drawable.logo_frame_42,
R.drawable.logo_frame_43,R.drawable.logo_frame_44,R.drawable.logo_frame_45,R.drawable.logo_frame_46,
R.drawable.logo_frame_47,R.drawable.logo_frame_48,R.drawable.logo_frame_49,R.drawable.logo_frame_50,
R.drawable.logo_frame_51,R.drawable.logo_frame_52,R.drawable.logo_frame_53,R.drawable.logo_frame_54,
R.drawable.logo_frame_55,R.drawable.logo_frame_56,R.drawable.logo_frame_57,R.drawable.logo_frame_58,
R.drawable.logo_frame_59,R.drawable.logo_frame_60,R.drawable.logo_frame_61,R.drawable.logo_frame_62,
R.drawable.logo_frame_63,R.drawable.logo_frame_64,R.drawable.logo_frame_65,R.drawable.logo_frame_66,
R.drawable.logo_frame_67,R.drawable.logo_frame_68,R.drawable.logo_frame_69,R.drawable.logo_frame_70,
R.drawable.logo_frame_71,R.drawable.logo_frame_72,R.drawable.logo_frame_73,R.drawable.logo_frame_74
};
public LogoAnimImageView(Context context) {
super(context);
}
public LogoAnimImageView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public LogoAnimImageView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
public void startLogoAnimation() {
mFrameIndex = 10;
mImageStack = new Stack<Drawable>();
for (int i=1;i<=mFrameIndex;i++) {
Drawable drawable = getDrawable(mResources[i]);
mImageStack.push(drawable);
}
mFrameIndex++;
mSplashActivity.runOnUiThread(new Runnable() {
#Override
public void run() {
new LogoAnimOperation().execute((Object)null);
}
});
}
public void setSplashActivityContext(SplashActivity splashActivity) {
this.mSplashActivity = splashActivity;
}
public void setAnimImageViewListener(LogoAnimImageViewInterface listener) {
this.mListener = listener;
}
private Drawable getDrawable(int id) {
Drawable drawable;
if(android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP){
drawable = mSplashActivity.getDrawable(id);
} else {
drawable = mSplashActivity.getResources().getDrawable(id);
}
return drawable;
}
private class LogoAnimOperation extends AsyncTask<Object,Void,String> {
#Override
protected String doInBackground(Object... params) {
int number=1;
while (mImageStack.size() > 1) {
try {
Thread.sleep(40);
} catch (InterruptedException e) {
e.printStackTrace();
}
final Drawable drawable = mImageStack.pop();
mSplashActivity.runOnUiThread(new Runnable() {
#Override
public void run() {
if(android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
LogoAnimImageView.this.setBackground(drawable);
}
else {
LogoAnimImageView.this.setBackgroundDrawable(drawable);
}
if (mFrameIndex < mResources.length) {
Drawable newDrawable = getDrawable(mResources[mFrameIndex]);
mImageStack.push(newDrawable);
mFrameIndex++;
}
}
});
}
return "";
}
#Override
protected void onPostExecute(String s) {
mSplashActivity.runOnUiThread(new Runnable() {
#Override
public void run() {
Drawable drawable = getDrawable(R.drawable.logo_frame_74);
if(android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
LogoAnimImageView.this.setBackground(drawable);
}
else {
LogoAnimImageView.this.setBackgroundDrawable(drawable);
}
}
});
mListener.animationEnd();
super.onPostExecute(s);
}
}
}
...but the only problem is that at the end of the animation the last
frame disappears and I am hitting my head whole day to understand why
is that happening with no success obviously.
The problem may lie in your AsyncTask's onPostExecute(String):
#Override
protected void onPostExecute(String s) {
mSplashActivity.runOnUiThread(new Runnable() {
#Override
public void run() {
Drawable drawable = getDrawable(R.drawable.logo_frame_74);
if(android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
LogoAnimImageView.this.setBackground(drawable);
} else {
LogoAnimImageView.this.setBackgroundDrawable(drawable);
}
}
});
mListener.animationEnd();
super.onPostExecute(s);
}
onPostExecute(String) will always be called on the UI thread. So, mSplashActivity.runOnUiThread(....) is redundant.
By using runOnUiThread(Runnable), you are posting to the UI thread's event queue. So, the runnable is executed when its turn comes up. However, the code after the mSplashActivity.runOnUiThread(....) call may get executed before the runnable. So, mListener.animationEnd() may be getting called before your LogoAnimImageView has a chance to display R.drawable.logo_frame_74.
But, this should not happen in your case. If runOnUiThread(Runnable) is called from the UI thread (which, it is), the Runnable is not posted to the event queue, and executed immediately instead.
I suspect that the real issue here is that there isn't any delay between the last frame of your animation (R.drawable.logo_frame_74), and launch of next activity. Perhaps you could comment out the call to mListener.animationEnd(), to check whether the animation ends at the last or second-last frame.
Although this is an interesting approach, and one I haven't seen before, I have to say that you are meddling with more threads than you need to. If you're trying to load Drawables as and when they are needed, there is a simpler way:
public class LogoAnimImageView extends ImageView {
....
....
// flag to indicate whether `mNextFrameDrawable` should continue loading the next frame
private boolean mStopAnimating;
// loads the next frame, and calls back to activity when done
private Runnable mNextFrameRunnable = new Runnable() {
#Override
public void run() {
if (!mStopAnimating) {
if (isFinishedAnimating() && mListener != null) {
mListener.animationEnd();
} else { // Load next frame
setViewBg(getNextFrameDrawable());
// Will load the next frame in 40 ms
postDelayed(this, 40L);
}
}
}
};
// This method can be set `public static` and placed in a separate `Utils` class
private void setViewBg(Drawable d) {
if(android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
setBackground(drawable);
} else {
setBackgroundDrawable(drawable);
}
}
private Boolean isFinishedAnimating() {
return mFrameIndex >= mResources.length;
}
// returns the next frame's drawable and increments the `mFrameIndex` pointer
private Drawable getNextFrameDrawable() {
return getDrawable(mResources[mFrameIndex++]);
}
// start animating
public void startLogoAnimation() {
mFrameIndex = 0;
mStopAnimating = false;
post(mNextFrameRunnable);
}
// stop animating
public void stopLogoAnimation() {
mStopAnimating = true;
removeCallbacks(mNextFrameRunnable);
}
....
....
}
AsyncTask is neither needed, nor designed to handle such scenarios.
I write the custom ImageView to display an animation with list of bitmaps. Here is my source code:
public class CustomImageView extends ImageView {
public CustomImageView(Context context) {
super(context);
}
public void startAnimation(List<BitmapDrawable> arrBitmapDelay, int[] durations) {
if (arrBitmapDelay.size() > 1 && arrBitmapDelay.size() == durations.length) {
final AnimationDrawable oAnimation = new AnimationDrawable();
oAnimation.setOneShot(false);
int i = 0;
for (BitmapDrawable oBitmapDelay : arrBitmapDelay) {
oAnimation.addFrame(oBitmapDelay, durations[i]);
i++;
}
if(getContext() instanceof Activity)
if(((Activity)getContext()).isFinishing())
return;
if(oAnimation.getNumberOfFrames()<=0) return;
setImageDrawable(oAnimation);
post(new Runnable() {
#Override
public void run() {
oAnimation.start();
}
});
}
}
}
And the result: https://goo.gl/photos/FSC5RaEE2ajfe23v6
You can see, it loop correctly time, but sometimes it flashing... Please help!
EDIT
I add code of reading list bitmap.
public void decodeAndShow() {
List<Bitmap> bitmaps = new ArrayList<>();
int[] duration = new int[20];
for (int i=0; i<20; i++) {
bitmaps.add(BitmapFactory.decodeFile(new File(getContext().getCacheDir(), "bitmapsample"+i+".png").getAbsolutePath()));
duration[i] = 100;
}
img.startAnimation(bitmaps, duration);
}
Sorry, because my project is too much complicated to copy here.
Add android:hardwareAccelerated="true" to your manifest, either for the or the . This ensures that your app uses the devices graphics card and should help with your animation.
I fixed by myself with a cheat. I don't know why it's OK.
This is my code:
public class CustomImageView extends ImageView {
private Runnable runningAnimation;
public CustomImageView(Context context) {
super(context);
}
public void startAnimation(List<BitmapDrawable> arrBitmapDelay, int[] durations) {
if(runningAnimation != null) {
this.removeCallbacks(runningAnimation);
}
if (arrBitmapDelay.size() > 1 && arrBitmapDelay.size() == durations.length) {
final AnimationDrawable oAnimation = new AnimationDrawable();
oAnimation.setOneShot(false);
int i = 0;
for (BitmapDrawable oBitmapDelay : arrBitmapDelay) {
oAnimation.addFrame(oBitmapDelay, durations[i]);
i++;
}
if(getContext() instanceof Activity)
if(((Activity)getContext()).isFinishing())
return;
if(oAnimation.getNumberOfFrames()<=0) return;
setImageDrawable(oAnimation);
runningAnimation = new Runnable() {
#Override
public void run() {
oAnimation.start();
}
}
post(runningAnimation);
}
}
}
Thanks for all the effort #Budius has made.
Most part of image work of my app could be handled by Picasso/Glide, however, some images are displayed in a TextView by Html.fromHtml. And the images in TextView are also used frequently.
However, I don't know how to implement getDrawable() method with Picasso/Glide for the ImageGetter passed to Html.fromHtml. Is it possible to share the same cache of Picasso/Glide for these pictures in TextView and other bitmaps?
Or should I use an custom LruCache instead to cache these pictures form ImageGetter separately? Will this way increase the risk of an OOM error? And I think it creates unnecessary workload to use 2 different systems for processing images.
Update: I tried to use .get() of Picasso, but the doc says
/**
* The result of this operation is not cached in memory because the underlying
* {#link Cache} implementation is not guaranteed to be thread-safe.
*/
So the cache is not used in this case.
Update:
The answer of #Budius is right, but code of setting bounds for the Drawable is missing, which leaves the Drawable not displayed in the TextView. So I modified the code in the DrawableWrapper class into:
public void setWrappedDrawable(Drawable drawable) {
if (mDrawable != null) {
mDrawable.setCallback(null);
}
mDrawable = drawable;
if (drawable != null) {
mDrawable.setBounds(0,0,mDrawable.getIntrinsicWidth(),mDrawable.getIntrinsicHeight());
drawable.setCallback(this);
}
}
Update:, the problem is still unsolved. If you implement the solution forementioned, there are some strange behaviors for the image in TextView. Sometimes the image could not be refreshed unless you switch to another app and switch back, and the position of image is severely incorrect.
Update: I have post all the code for test below. There're still some bugs. Without a placeholder, it still throws an NPE. With a placeholder, the behavior is very strange. The first time I enter TestActivity, it shows the placeholder but it won't change into the downloaded pic. But after I switch to another app or press a back button and enter TestActivity again, the pic is displayed(maybe because it's in the cache?).
And also the size of pic is right but the place is still not left for the image. And if I call mDrawable.setBounds(getBounds()); instead of mDrawable.setBounds(0,0,getIntrinsicWidth(),getIntrinsicHeight());, it will not be displayed.
DrawableWrapper
public class DrawableWrapper extends Drawable implements Drawable.Callback {
private Drawable mDrawable;
public DrawableWrapper(Drawable drawable) {
setWrappedDrawable(drawable);
}
#Override
public void draw(Canvas canvas) {
mDrawable.draw(canvas);
}
#Override
public int getIntrinsicWidth() {
return 384;
}
#Override
public int getIntrinsicHeight() {
return 216;
}
//... other delegation methods are omitted
public void setWrappedDrawable(Drawable drawable) {
if (mDrawable != null) {
mDrawable.setCallback(null);
}
mDrawable = drawable;
if (drawable != null) {
mDrawable.setBounds(0,0,getIntrinsicWidth(),getIntrinsicHeight());
drawable.setCallback(this);
}
}
}
PicassoTargetDrawable
public class PicassoTargetDrawable extends DrawableWrapper
implements Target {
private Context context;
public PicassoTargetDrawable(Context context) {
super(new ColorDrawable(0));
// use application context to not leak activity
this.context = context.getApplicationContext();
}
public void onBitmapFailed(Drawable errorDrawable) {
setWrappedDrawable(errorDrawable);
invalidateSelf();
}
public void onBitmapLoaded(Bitmap bitmap, Picasso.LoadedFrom from) {
setWrappedDrawable(new BitmapDrawable(context.getResources(), bitmap));
context = null;
invalidateSelf();
}
public void onPrepareLoad(Drawable placeHolderDrawable) {
setWrappedDrawable(placeHolderDrawable);
invalidateSelf();
}
}
TestActivity
public class TestActivity extends FragmentActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
TextView textView = new TextView(this);
textView.setLayoutParams(new FrameLayout.LayoutParams(FrameLayout.LayoutParams.MATCH_PARENT, FrameLayout.LayoutParams.MATCH_PARENT));
setContentView(textView);
String html = "<div>test<br/>" +
"<img src=\"http://i2.cdn.turner.com/money/dam/assets/150910165544-elon-evo-open-still-384x216.png\"></img>" +
"<br/>/test</div>";
textView.setText(Html.fromHtml(html, new Html.ImageGetter() {
#Override
public Drawable getDrawable(String source) {
PicassoTargetDrawable d = new PicassoTargetDrawable(TestActivity.this);
Picasso.with(TestActivity.this)
.load(source)
//add placeholder here
.into(d);
return d;
}
}, null));
}
}
My Suggestion is to return a wrap drawable. And keep using Picasso to download the image.
On the following link you can find an DrawableWrapper, it's from Googles support library, but it's not part of the public docs, so I would just copy the whole code into your project https://android.googlesource.com/platform/frameworks/support/+/master/v7/appcompat/src/android/support/v7/graphics/drawable/DrawableWrapper.java
And then you create a PicassoTargetDrawable from it.
public class PicassoTargetDrawable extends DrawableWrapper
implements Picasso.Target {
private Context context;
public PicassoTargetDrawable(Context context) {
super(new ColorDrawable(0));
// use application context to not leak activity
this.context = context.getApplicationContext();
}
public void onBitmapFailed(Drawable errorDrawable) {
setWrappedDrawable(errorDrawable);
invalidateSelf();
}
public void onBitmapLoaded(Bitmap bitmap, Picasso.LoadedFrom from) {
setWrappedDrawable(new BitmapDrawable(context.getResources(), bitmap));
context = null;
invalidateSelf();
}
public void onPrepareLoad(Drawable placeHolderDrawable) {
setWrappedDrawable(placeHolderDrawable);
invalidateSelf();
}
}
Then it's just a matter of loading it up
public void Drawable getDrawable(String source) {
PicassoTargetDrawable d = new PicassoTargetDrawable(context);
Picasso.with(context)
.load(source)
..... add here onError and placeholder drawables
.into(d);
return d;
}
PS.:
I wrote all this without looking up too much, there will probably be a few typos and a few issues to sort it out, but it's certainly enough for you to understand the concept.
update:
Just correcting your code.
The TextView already told the WrapDrawable the Bounds it should use. If you're telling the new mDrawable that it can use whatever size it wants, it will use whatever size it wants. So instead of passing its own intrinsic width/height, you should pass the size that was give to the WrapDrawable
public void setWrappedDrawable(Drawable drawable) {
if (mDrawable != null) {
mDrawable.setCallback(null);
}
mDrawable = drawable;
if (drawable != null) {
mDrawable.setBounds(getBounds());
drawable.setCallback(this);
}
}
As my previous question, I am trying "GLSurfaceView + TextureView" to show camera preview in one GLSurfaceView and multiple TextureViews, but facing some problems...
In GLSurfaceView render thread, I tried to share built-in EGLContext to TextureView, create a EGL surface by TextureView's surfaceTexture, then use GLES to draw on it.
#Override
public void onDrawFrame(final GL10 gl) {
// GLES draw on GLSurfaceView
renderToTextureView();
}
private void renderToTextureView() {
saveEGLState();
for(TextureViewItem item : mTextureViewItemList) {
item.render(mSavedEglContext);
}
restoreEGLState();
}
private void saveEGLState() {
mSavedEglDisplay = EGL14.eglGetCurrentDisplay();
mSavedEglContext = EGL14.eglGetCurrentContext();
mSavedEglDrawSurface = EGL14.eglGetCurrentSurface(EGL14.EGL_DRAW);
mSavedEglReadSurface = EGL14.eglGetCurrentSurface(EGL14.EGL_READ);
}
private void restoreEGLState() {
if (!EGL14.eglMakeCurrent(mSavedEglDisplay, mSavedEglDrawSurface, mSavedEglReadSurface, mSavedEglContext)) {
throw new RuntimeException("eglMakeCurrent failed");
}
}
public class TextureViewItem implements TextureView.SurfaceTextureListener {
private static EglCore sEglCore;
private WindowSurface mWindowSurface;
public void render(EGLContext sharedContext) {
if(mSavedSurfaceTexture == null) return;
getWindowSurface(sharedContext).makeCurrent();
// GLES draw on TextureView
getWindowSurface(sharedContext).swapBuffers();
}
private WindowSurface getWindowSurface(EGLContext sharedContext) {
if(sEglCore == null) {
sEglCore = new EglCore(sharedContext, EglCore.FLAG_TRY_GLES3);
}
if(mWindowSurface == null) {
mWindowSurface = new WindowSurface(mEglCore, mSavedSurfaceTexture);
}
return mWindowSurface;
}
#Override
public void onSurfaceTextureAvailable(SurfaceTexture st, int width, int height) {
if (mSavedSurfaceTexture == null) {
mSavedSurfaceTexture = st;
}
}
#Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture st) {
if (mWindowSurface != null) {
mWindowSurface.release();
}
if (sEglCore != null) {
sEglCore.release();
}
mSavedSurfaceTexture = null;
return true;
}
}
Everything works fine except press "back" key. I call GLSurfaceView's onPause() when the activity pauses, it caused swapBuffers (EGL14.eglSwapBuffers) won't return...
Some suspected logcat messages also
W/WindowManager(1077): Window freeze timeout expired.
I/WindowManager(1077): Screen frozen for +2s42ms due to Window ..
Anyone knows why? And any way to solve this problem?
Thanks.
on a child layout (View) is there a callback for when the view is removed from it's parent? I need to recycle some images when the view is done. I've been looking around on the web for what to do, but haven't found anything helpful yet.
I've been looking for something like this too. The best I can find is View.OnAttachStateChangeListener. I doubt it's ideal, as it's the callback for when the View is added & removed from the Window - not the parent, but it's sufficient for my needs.
Instead of registering a new listener, you can override onDetachedFromWindow in your custom View code.
I fall in that trap what marmor said:)
#Override
protected void onDetachedFromWindow() { I want to do something here, sometimes called sometimes not!!}
protected void onAttachedToWindow() {It is working fine, always}
This code is in a CustomView.
The calling code is:
contentHolder.removeAllViews();
// ... init my CustomView ...
contentHolder.addView(myCustomView);
contentHolder.requestLayout();// useless, not need
contentHolder.invalidate();// useless, not need
To understand why is not working you have to go inside Android API:
public void removeAllViews() {
removeAllViewsInLayout();
requestLayout();
invalidate(true);
}
public void removeAllViewsInLayout() {
final int count = mChildrenCount;
if (count <= 0) {
return;
}
final View[] children = mChildren;
mChildrenCount = 0;
final View focused = mFocused;
final boolean detach = mAttachInfo != null;
boolean clearChildFocus = false;
needGlobalAttributesUpdate(false);
for (int i = count - 1; i >= 0; i--) {
final View view = children[i];
if (mTransition != null) {
mTransition.removeChild(this, view);
}
if (view == focused) {
view.unFocus(null);
clearChildFocus = true;
}
view.clearAccessibilityFocus();
cancelTouchTarget(view);
cancelHoverTarget(view);
if (view.getAnimation() != null ||
(mTransitioningViews != null && mTransitioningViews.contains(view))) {
addDisappearingView(view);
} else if (detach) {
view.dispatchDetachedFromWindow();
}
if (view.hasTransientState()) {
childHasTransientStateChanged(view, false);
}
dispatchViewRemoved(view);
view.mParent = null;
children[i] = null;
}
if (clearChildFocus) {
clearChildFocus(focused);
if (!rootViewRequestFocus()) {
notifyGlobalFocusCleared(focused);
}
}
}
The key is here:
if (view.getAnimation() != null ||
(mTransitioningViews != null && mTransitioningViews.contains(view))) {
So, if you have animation ( and in 1 case I have and in 9 cases not) it will not called the onDetachedFromWindow() and it will mess the whole UI :)
public void endViewTransition(View view) {
if (mTransitioningViews != null) {
mTransitioningViews.remove(view);
final ArrayList<View> disappearingChildren = mDisappearingChildren;
if (disappearingChildren != null && disappearingChildren.contains(view)) {
disappearingChildren.remove(view);
if (mVisibilityChangingChildren != null &&
mVisibilityChangingChildren.contains(view)) {
mVisibilityChangingChildren.remove(view);
} else {
if (view.mAttachInfo != null) {
view.dispatchDetachedFromWindow();
}
if (view.mParent != null) {
view.mParent = null;
}
}
invalidate();
}
}
}
Again in some cases will be called even with animation.
addDisappearingView(view);
The accepted answer suggest something like this:
addOnAttachStateChangeListener(new OnAttachStateChangeListener() {
#Override
public void onViewAttachedToWindow(View v) {
}
#Override
public void onViewDetachedFromWindow(View v) {
System.out.println("MyCustomView.onViewDetachedFromWindow");
}
});
Sadly on animation will not print the desired text.
Some important code from android.view.ViewGroup API:
void dispatchViewRemoved(View child) {
onViewRemoved(child);
if (mOnHierarchyChangeListener != null) {
mOnHierarchyChangeListener.onChildViewRemoved(this, child);
}
}
public void onViewRemoved(View child) {
}
So, you can override your RelativeLayout for this method.
My animation is an infinite animation, and it will not be called very soon any of the methods!
If you have an infinite animation the correct way is to write this code, when you call remove all views:
if(contentHolder.getChildCount() > 0 ){
View child0 = contentHolder.getChildAt(0);
Animation animation = child0.getAnimation();
if(animation != null) {
animation.cancel();
child0.clearAnimation();
}
}
contentHolder.removeAllViews();
Now it will be called the protected void onDetachedFromWindow()!
The Android KTX (Core KTX) library gives you a nice solution for this.
You'll need this dependency: androidx.core:core-ktx:1.3.0
You can then call a function "doOnDetach" to signal you want to run some code (once) when the view is removed from the window:
fun myInitCode() {
...
myView.doOnDetach(this::doOnMyViewDetachFromWindow)
...
}
fun doOnMyViewDetachFromWindow(view: View) {
... put your image cleanup code here ...
}
You can pass a lambda to "doOnDetach" but a method reference as shown above may be cleaner, depending on how much work you have to do.
The description of doOnDetach is as follows:
androidx.core.view ViewKt.class public inline fun View.doOnDetach(
crossinline action: (View) → Unit ): Unit
Performs the given action when this view is detached from a window. If
the view is not attached to a window the action will be performed
immediately, otherwise the action will be performed after the view is
detached from its current window. The action will only be invoked
once, and any listeners will then be removed.