java.lang.OutOfMemoryError: bitmap size exceeds VM budget - Android

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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?

13 Answers

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.

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.

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();
    }

}
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