I have a piece of code that displays camera preview in a TextureView. Once in a while (let's say the user presses a button) I obtain a bitmap from the TextureView and set it for display in an ImageView, like this:
private void freezeFrame() {
textureView.getBitmap(freezeBitmap);
imageView.setImageBitmap(freezeBitmap);
}
The freezeBitmap is pre-allocated and reused on multiple calls to the above method.
The problem is that the ImageView keeps showing the state of the bitmap from the first call to freezeFrame(). Calling imageView.invalidate() doesn't help.
The problem disappears when I do one of the following:
set imageView to use a software layer (this leads me to believe the bitmap is correctly obtained from the textureView but not uploaded to the GPU in hardware mode),
create a new bitmap on each call to getBitmap(),
modify the bitmap, e.g. with freezeBitmap.setPixel(0, 0, 0).
So I wonder: why doesn't ImageView "notice" that the bitmap has been updated by TextureView.getBitmap yet it does notice the change performed by setPixel()?
Is there a good way to force the update?
I'm trying to create my first android app, so I'm really new to android development. I'm trying to make a nice background image for my app. I made an image that is the exact dimensions of the device, but when I try to load it, i get the error "Failed to allocate a 218748 byte allocation with 217220 free bytes and 212KB until OOM" Here's my code:
#Override
protected void onDraw(Canvas canvas) {
drawBackground(canvas);
protected void drawBackground(Canvas canvas) {
Bitmap background = Bitmap.createBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.background2));
canvas.drawBitmap(background, 0, 0, null);
I've tried scaling it down, which works, but then it doesn't fill the entire screen. How do I resolve this issue?
You should recycle bitmap after canvas.drawBitmap(background, 0, 0, null);, or create bitmap once, in the constructor, and then use it, it is very costly to create bitmap each time in the onDraw method, it even costly to create simple objects in the onDraw, you shuold avoid from it, android:largeHeap="true" and System.gc() can't help in this case. Read this
Custom Drawing
Creating objects ahead of time is an important optimization. Views are redrawn very frequently, and many drawing objects require expensive initialization. Creating drawing objects within your onDraw() method significantly reduces performance and can make your UI appear sluggish.
There is blog that will help you to detect and prevent Out of memory issue. I wrote this based on a real problem I faced and here is the link
If you got stuck anywhere in the tutorial please let me know we can discuss and if you want to add something please suggest.
I have some code which is loading an image into an OpenGL texture. In the process, I end up loading 3 bitmaps, since I need to load the original bitmap (sized appropriately for the display) and reorient the bitmap based on EXIF data. I'm very quickly calling .recycle() on each bitmap, but I'm noticing that my memory doesn't seem to change.
Here's what the Memory Monitor shows:
As you can see, after loading the image I'm using about 60MB of memory. When I rotate the device that drops off a bit then comes back up. That leads me to think there is no leak, since the memory never goes above that.
When I click the GC button in the memory analyzer, my memory footprint drops dramatically to around 8 MB. This makes sense as the three bitmaps created during the process were recycled, so can be garbage collected. Then you can see that when I rotate again and the activity is rebuilt, the memory jumps right back up.
Here's my code to show you why so many bitmaps are created and when they're recycled.
void layoutImage() {
...
Bitmap bitmap = loadOrientedConstrainedBitmapWithBackouts(...);
imageTexture = new GLTexture(bitmap);
bitmap.recycle(); // recycle bitmap 2
}
Bitmap loadOrientedConstrainedBitmapWithBackouts(Context context, Uri uri, int maxSize) {
...
Bitmap bitmap = loadBitmapWithBackouts(context, uri, sampleSize); // create bitmap 1
...
Bitmap out = orientBitmap(bitmap, orientation); // create bitmap 2
bitmap.recycle(); // recycle bitmap 1
return out;
}
Bitmap orientBitmap(Bitmap source, int orientation) {
...
return Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight, matrix, true); // create bitmap 3
}
I'm not really sure that this is a problem, so to speak, since the memory isn't climbing (so no leak), but I'm curious when it stays so high. Since forcing a garbage collection clears it just fine, should I assume that if the system needs that memory it will be collected on the next GC pass? It's been running the whole time I've been writing this and is still sitting comfortably at 60 MB.
Question 1: Can I just trust that the garbage collector will take that memory back if needed?
Also, if we're supposed to be so judiciously recycling our bitmaps, why do so many of the Bitmap methods say things like "The new bitmap may be the same object as source, or a copy may have been made." Do I really have to check the equality every time I use those methods to recycle the bitmap if it's a different object?
Question 2: When using Bitmap creation methods, that may or may not return the same bitmap or a copy, do I need to check source and output equality to recycle the source if it's a copy?
Edit:
I have tried analyzing this with MAT, using a heap dump at peak usage (should be 60 MB), but it only reports 18.2 MB of usage and nothing unusual looking. Could they be reading things differently?
Question 1: Can I just trust that the garbage collector will take that memory back if needed?
Yes. If the incoming references are cleared, the garbage collector will take the memory when it is needed (typically for a new allocation). Calling recycle() doesn't help this process along or make it happen any faster.
The recycle() method exists because Bitmap objects were not counted against the heap until Android 3.0; so the method was helpful to assist the GC since it didn't otherwise have a record of that memory counted against its heap. In 3.0+, the memory is tracked against the heap so this extra bookkeeping isn't necessary anymore.
Question 2: When using Bitmap creation methods, that may or may not return the same bitmap or a copy, do I need to check source and output equality to recycle the source if it's a copy?
The createBitmap() method will return the same object if:
The source is immutable
x and y are both zero
width and height match the source width and height
No transformation matrices have been applied
Since it looks like you are passing in a transformation matrix, you will always get a copy unless the matrix is identity for some reason. But again, no real need to recycle() unless you are still supporting 2.x versions.
i try to rotate 3 imageViews (or better the Bitmaps behind them) every 10-100ms.
i do the rotation like this:
ImageView ivLoad;
Bitmap bMapLoad;
....
Matrix mat=new Matrix();
mat.reset();
mat.postScale(1.55f, 1.55f);
mat.postRotate((float)currentLoadDegree+(float)LoadDegree);
bMapLoad = Bitmap.createBitmap(bMapLoadgr, 0, 0, bMapLoadgr.getWidth(), bMapLoadgr.getHeight(), mat, true);
ivLoad.setImageBitmap(bMapLoad);
ivLoad.setScaleType(ScaleType.CENTER);
....
the first time i start the app everthing works fine.
second time also works
but the 3rd time i start the app it crashs with the following error:
03-27 10:01:09.234: E/AndroidRuntime(3603): java.lang.OutOfMemoryError
03-27 10:01:09.234: E/AndroidRuntime(3603): at android.graphics.Bitmap.nativeCreate(Native Method)
03-27 10:01:09.234: E/AndroidRuntime(3603): at android.graphics.Bitmap.createBitmap(Bitmap.java:605)
03-27 10:01:09.234: E/AndroidRuntime(3603): at android.graphics.Bitmap.createBitmap(Bitmap.java:551)
after trying around a long time i found out that when i call System.exit(0) in the onDestroy methode everthing works.
now i don't know if there would be a better way because on google a lot of peaople mean that System.exit(0) is unsafe.
so will i get problems with this?
Instead of rotating the Bitmap, you could rotate the canvas you are drawing on.
canvas.save();
canvas.translate(-canvasWidth/2, -canvasHeight/2);
canvas.rotate(degrees)
canvas.drawBitmap( ... )
canvas.translate(-canvasWidth/2, -canvasHeight/2);
canvas.restore();
Now you only get a new bitmap, when the image itself is updated, even though you can rotate it as frequent as you like. But if you get a new Bitmap, you still need to call Bitmap.recycle() on the old one.
You shouldn't recreate the bitmap on every step of the rotation, instead you should just try to draw it rotated. That's also possible with a Matrix (what you already use) and will avoid the excessive memory usage.
Android: How to rotate a bitmap on a center point
You get OutOfMemoryError because you load the Bitmap every time you rotate ImageView. You should consider reusing already loaded bitmap. Also call Bitmap.recycle() method when you do not need the bitmap any more.
I developed an application that uses lots of images on Android.
The app runs once, fills the information on the screen (Layouts, Listviews, Textviews, ImageViews, etc) and user reads the information.
There is no animation, no special effects or anything that can fill the memory.
Sometimes the drawables can change. Some are android resources and some are files saved in a folder in the SDCARD.
Then the user quits (the onDestroy method is executed and app stays in memory by the VM ) and then at some point the user enters again.
Each time the user enters to the app, I can see the memory growing more and more until user gets the java.lang.OutOfMemoryError.
So what is the best/correct way to handle many images?
Should I put them in static methods so they are not loaded all the time?
Do I have to clean the layout or the images used in the layout in a special way?
One of the most common errors that I found developing Android Apps is the “java.lang.OutOfMemoryError: Bitmap Size Exceeds VM Budget” error. I found this error frequently on activities using lots of bitmaps after changing orientation: the Activity is destroyed, created again and the layouts are “inflated” from the XML consuming the VM memory available for bitmaps.
Bitmaps on the previous activity layout are not properly de-allocated by the garbage collector because they have crossed references to their activity. After many experiments I found a quite good solution for this problem.
First, set the “id” attribute on the parent view of your XML layout:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/RootView"
>
...
Then, on the onDestroy() method of your Activity, call the unbindDrawables() method passing a reference to the parent View and then do a System.gc().
#Override
protected void onDestroy() {
super.onDestroy();
unbindDrawables(findViewById(R.id.RootView));
System.gc();
}
private void unbindDrawables(View view) {
if (view.getBackground() != null) {
view.getBackground().setCallback(null);
}
if (view instanceof ViewGroup) {
for (int i = 0; i < ((ViewGroup) view).getChildCount(); i++) {
unbindDrawables(((ViewGroup) view).getChildAt(i));
}
((ViewGroup) view).removeAllViews();
}
}
This unbindDrawables() method explores the view tree recursively and:
Removes callbacks on all the background drawables
Removes children on every viewgroup
It sounds like you have a memory leak. The problem isn't handling many images, it's that your images aren't getting deallocated when your activity is destroyed.
It's difficult to say why this is without looking at your code. However, this article has some tips that might help:
http://android-developers.blogspot.de/2009/01/avoiding-memory-leaks.html
In particular, using static variables is likely to make things worse, not better. You might need to add code that removes callbacks when your application redraws -- but again, there's not enough information here to say for sure.
To avoid this problem you can use native method Bitmap.recycle() before null-ing Bitmap object (or setting another value). Example:
public final void setMyBitmap(Bitmap bitmap) {
if (this.myBitmap != null) {
this.myBitmap.recycle();
}
this.myBitmap = bitmap;
}
And next you can change myBitmap w/o calling System.gc() like:
setMyBitmap(null);
setMyBitmap(anotherBitmap);
I've ran into this exact problem. The heap is pretty small so these images can get out of control rather quickly in regards to memory. One way is to give the garbage collector a hint to collect memory on a bitmap by calling its recycle method.
Also, the onDestroy method is not guaranteed to get called. You may want to move this logic/clean up into the onPause activity. Check out the Activity Lifecycle diagram/table on this page for more info.
This explanation might help:
http://code.google.com/p/android/issues/detail?id=8488#c80
"Fast Tips:
1) NEVER call System.gc() yourself. This has been propagated as a fix here, and it doesn't work. Do not do it. If you noticed in my explanation, before getting an OutOfMemoryError, the JVM already runs a garbage collection so there is no reason to do one again (its slowing your program down). Doing one at the end of your activity is just covering up the problem. It may causes the bitmap to be put on the finalizer queue faster, but there is no reason you couldn't have simply called recycle on each bitmap instead.
2) Always call recycle() on bitmaps you don't need anymore. At the very least, in the onDestroy of your activity go through and recycle all the bitmaps you were using. Also, if you want the bitmap instances to be collected from the dalvik heap faster, it doesn't hurt to clear any references to the bitmap.
3) Calling recycle() and then System.gc() still might not remove the bitmap from the Dalvik heap. DO NOT BE CONCERNED about this. recycle() did its job and freed the native memory, it will just take some time to go through the steps I outlined earlier to actually remove the bitmap from the Dalvik heap. This is NOT a big deal because the large chunk of native memory is already free!
4) Always assume there is a bug in the framework last. Dalvik is doing exactly what its supposed to do. It may not be what you expect or what you want, but its how it works. "
I had the exact same problem. After a few testing I found that this error is appearing for large image scaling. I reduced the image scaling and the problem disappeared.
P.S. At first I tried to reduce the image size without scaling the image down. That did not stop the error.
Following points really helped me a lot. There might be other points too, but these are very crucial:
Use application context(instead of activity.this) where ever possible.
Stop and release your threads in onPause() method of activity
Release your views / callbacks in onDestroy() method of activity
I suggest a convenient way to solve this problem.
Just assign the attribute "android:configChanges" value as followed in the Mainfest.xml for your errored activity.
like this:
<activity android:name=".main.MainActivity"
android:label="mainActivity"
android:configChanges="orientation|keyboardHidden|navigation">
</activity>
the first solution I gave out had really reduced the frequency of OOM error to a low level. But, it did not solve the problem totally. And then I will give out the 2nd solution:
As the OOM detailed, I have used too much runtime memory. So, I reduce the picture size in ~/res/drawable of my project. Such as an overqualified picture which has a resolution of 128X128, could be resized to 64x64 which would also be suitable for my application. And after I did so with a pile of pictures, the OOM error doesn't occur again.
I too am frustrated by the outofmemory bug. And yes, I too found that this error pops up a lot when scaling images. At first I tried creating image sizes for all densities, but I found this substantially increased the size of my app. So I'm now just using one image for all densities and scaling my images.
My application would throw an outofmemory error whenever the user went from one activity to another. Setting my drawables to null and calling System.gc() didn't work, neither did recycling my bitmapDrawables with getBitMap().recycle(). Android would continue to throw the outofmemory error with the first approach, and it would throw a canvas error message whenever it tried using a recycled bitmap with the second approach.
I took an even third approach. I set all views to null and the background to black. I do this cleanup in my onStop() method. This is the method that gets called as soon as the activity is no longer visible. If you do it in the onPause() method, users will see a black background. Not ideal. As for doing it in the onDestroy() method, there is no guarantee that it will get called.
To prevent a black screen from occurring if the user presses the back button on the device, I reload the activity in the onRestart() method by calling the startActivity(getIntent()) and then finish() methods.
Note: it's not really necessary to change the background to black.
The BitmapFactory.decode* methods, discussed in the Load Large Bitmaps Efficiently lesson, should not be executed on the main UI thread if the source data is read from disk or a network location (or really any source other than memory). The time this data takes to load is unpredictable and depends on a variety of factors (speed of reading from disk or network, size of image, power of CPU, etc.). If one of these tasks blocks the UI thread, the system flags your application as non-responsive and the user has the option of closing it (see Designing for Responsiveness for more information).
Well I've tried everything I found on the internet and none of them worked. Calling System.gc() only drags down the speed of app. Recycling bitmaps in onDestroy didn't work for me too.
The only thing that works now is to have a static list of all the bitmap so that the bitmaps survive after a restart. And just use the saved bitmaps instead of creating new ones every time the activity if restarted.
In my case the code looks like this:
private static BitmapDrawable currentBGDrawable;
if (new File(uriString).exists()) {
if (!uriString.equals(currentBGUri)) {
freeBackground();
bg = BitmapFactory.decodeFile(uriString);
currentBGUri = uriString;
bgDrawable = new BitmapDrawable(bg);
currentBGDrawable = bgDrawable;
} else {
bgDrawable = currentBGDrawable;
}
}
I had the same problem just with switching the background images with reasonable sizes. I got better results with setting the ImageView to null before putting in a new picture.
ImageView ivBg = (ImageView) findViewById(R.id.main_backgroundImage);
ivBg.setImageDrawable(null);
ivBg.setImageDrawable(getResources().getDrawable(R.drawable.new_picture));
FWIW, here's a lightweight bitmap-cache I coded and have used for a few months. It's not all-the-bells-and-whistles, so read the code before you use it.
/**
* Lightweight cache for Bitmap objects.
*
* There is no thread-safety built into this class.
*
* Note: you may wish to create bitmaps using the application-context, rather than the activity-context.
* I believe the activity-context has a reference to the Activity object.
* So for as long as the bitmap exists, it will have an indirect link to the activity,
* and prevent the garbaage collector from disposing the activity object, leading to memory leaks.
*/
public class BitmapCache {
private Hashtable<String,ArrayList<Bitmap>> hashtable = new Hashtable<String, ArrayList<Bitmap>>();
private StringBuilder sb = new StringBuilder();
public BitmapCache() {
}
/**
* A Bitmap with the given width and height will be returned.
* It is removed from the cache.
*
* An attempt is made to return the correct config, but for unusual configs (as at 30may13) this might not happen.
*
* Note that thread-safety is the caller's responsibility.
*/
public Bitmap get(int width, int height, Bitmap.Config config) {
String key = getKey(width, height, config);
ArrayList<Bitmap> list = getList(key);
int listSize = list.size();
if (listSize>0) {
return list.remove(listSize-1);
} else {
try {
return Bitmap.createBitmap(width, height, config);
} catch (RuntimeException e) {
// TODO: Test appendHockeyApp() works.
App.appendHockeyApp("BitmapCache has "+hashtable.size()+":"+listSize+" request "+width+"x"+height);
throw e ;
}
}
}
/**
* Puts a Bitmap object into the cache.
*
* Note that thread-safety is the caller's responsibility.
*/
public void put(Bitmap bitmap) {
if (bitmap==null) return ;
String key = getKey(bitmap);
ArrayList<Bitmap> list = getList(key);
list.add(bitmap);
}
private ArrayList<Bitmap> getList(String key) {
ArrayList<Bitmap> list = hashtable.get(key);
if (list==null) {
list = new ArrayList<Bitmap>();
hashtable.put(key, list);
}
return list;
}
private String getKey(Bitmap bitmap) {
int width = bitmap.getWidth();
int height = bitmap.getHeight();
Config config = bitmap.getConfig();
return getKey(width, height, config);
}
private String getKey(int width, int height, Config config) {
sb.setLength(0);
sb.append(width);
sb.append("x");
sb.append(height);
sb.append(" ");
switch (config) {
case ALPHA_8:
sb.append("ALPHA_8");
break;
case ARGB_4444:
sb.append("ARGB_4444");
break;
case ARGB_8888:
sb.append("ARGB_8888");
break;
case RGB_565:
sb.append("RGB_565");
break;
default:
sb.append("unknown");
break;
}
return sb.toString();
}
}