Android custom view Bitmap memory leak

Question

I've got a custom view in which I need to draw two bitmaps, one is a background, representing the image of a map and one is a pin which will be drawn on top/left position in canvas.

The both images are drawn onDraw and remain the same during the live of the activity that contains the view. After a while I get a

OutOfMemoryError: bitmap size exceeds VM budget

This means that I have a leak and the bitmaps don't get garbage collected. I asked this question before, but now the situation changed a little. I made a init method where I set the bitmaps I want to use but this still isn't a good approach, the error appears later, but still there.

Here is the code

public class MyMapView extends View {
private int xPos = 0;
private int yPos = 0;
private int space = 0;

private Bitmap resizedBitmap;
private Bitmap position;
private Bitmap mapBitmap;

public void setMapBitmap(Bitmap value) {
    this.mapBitmap =  value;
}

public MyMapView(Context context) {
 super(context);
}

public MyMapView(Context context, AttributeSet attrs) {
 super(context, attrs);
}

public MyMapView(Context context, AttributeSet attrs, int defStyle) {
 super(context, attrs, defStyle);
}

public void init(final Context context) {
 Paint paint = new Paint();
    paint.setFilterBitmap(true);

    int width = getMeasuredWidth();
    int height = getMeasuredHeight();

    resizedBitmap = Bitmap.createScaledBitmap(mapBitmap, height, height, true);
    position = BitmapFactory.decodeResource(getContext().getResources(), R.drawable.position);
    space = (width - resizedBitmap.getWidth()) / 2;
}

public void destroy()
{
 resizedBitmap.recycle();
 resizedBitmap=null;
 position.recycle();
 position=null;
 mapBitmap.recycle();
 mapBitmap=null;
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  setMeasuredDimension(MeasureSpec.getSize(widthMeasureSpec), MeasureSpec.getSize(heightMeasureSpec));
}

@Override
protected void onDraw(Canvas canvas) {

     if (mapBitmap != null) {
         canvas.drawBitmap(resizedBitmap, space, 0, null);
     }

     if (xPos != 0 && yPos != 0) {
         canvas.translate(xPos + space - position.getWidth() / 2, yPos - position.getHeight() / 2);
         canvas.drawBitmap(position, new Matrix(), new Paint());

     }
}

 public void updatePosition(int xpos, int ypos)
 {
   xPos = xpos;
      yPos = ypos;
      invalidate();
 }
}

I call the setMapBitmap() and init() on onCreate of the activity that contains the view. In there I know what bitmap will be used as map. onPause of the activity I call the destroy() of the view. I still get errors. I've read this this but I don't know how to adapt it on my case

I AM OPEN TO ANY OTHER SOLUTION. Please note that I need to resize the map bitmap (based on the height of the layout that contains it in mai activity) and still be able to draw the position on correct place.

Do you run this on emulator or device? Under debugger or without it? — Peter Knego, Nov 16 '10 at 22:32
I ran it on my emulator without debugging it. With debugging activated is too slow. Thank you. — Alin, Nov 17 '10 at 06:00
Why don't you clear the mapBitmap when you have resizedBitmap ? Another thing is resize the bitmap when you need it i.e. resize the bitmap in onDraw and then clear it out so that it can be GC'ed. — Karan, Nov 24 '10 at 07:17

score 12 · Accepted Answer · edited May 23 '17 at 12:10

You obviously have a memory leak. Read how to avoid memory leaks and how to find memory leaks.

Here is a your code refactored to use WeakReference:

public class MyMapView extends View {
    private int xPos = 0;
    private int yPos = 0;
    private int space = 0;

    private WeakReference<Bitmap> resizedBitmap;
    private WeakReference<Bitmap> position;
    private WeakReference<Bitmap> mapBitmap;

    public void setMapBitmap(Bitmap value) {
        this.mapBitmap = new WeakReference<Bitmap>(value);
    }

    public MyMapView(Context context) {
        super(context);
    }

    public MyMapView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MyMapView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public void init(Bitmap mapBitmap) {
        Paint paint = new Paint();
        paint.setFilterBitmap(true);

        int width = getMeasuredWidth();
        int height = getMeasuredHeight();

        resizedBitmap = new WeakReference<Bitmap>(Bitmap.createScaledBitmap(
            mapBitmap, width, height, true));
        position = new WeakReference(BitmapFactory.decodeResource(
            getContext().getResources(), R.drawable.position));
        space = (width - resizedBitmap.get().getWidth()) / 2;
    }

//    public void destroy() {
//        resizedBitmap.recycle();
//        resizedBitmap = null;
//        position.recycle();
//        position = null;
//        mapBitmap.recycle();
//        mapBitmap = null;
//    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        setMeasuredDimension(MeasureSpec.getSize(widthMeasureSpec),
            MeasureSpec.getSize(heightMeasureSpec));
    }

    @Override
    protected void onDraw(Canvas canvas) {

        if (mapBitmap != null) {
            canvas.drawBitmap(resizedBitmap.get(), space, 0, null);
        }

        if (xPos != 0 && yPos != 0) {
            canvas.translate(xPos + space - position.get().getWidth() / 2, 
                yPos - position.get().getHeight() / 2);
            canvas.drawBitmap(position.get(), new Matrix(), null);

        }
    }

    public void updatePosition(int xpos, int ypos) {
        xPos = xpos;
        yPos = ypos;
        invalidate();
    }
}

Thank you Peter. I installed Eclipse Memory Analyzer and will check if it works fine now. if it is, I'll mark the answer. — Alin, Nov 24 '10 at 07:32
This was a solution until I found a problem: after a while the map image disappears... my guess is that it gets garbage collected. — Alin, Dec 05 '10 at 10:50
Of course. You need to check if `weakReference.get()` gives you `null` and in this case load a Bitmap again. You could extend WeakReference to a BitmapWeakReference and override `.get()` method so that it checks if `super.get()` is null and reloads a picture. — Peter Knego, Dec 05 '10 at 14:56
WeakReferences only should be used when you dont want a reference to the bitmap if you dont need to on low memory. This is not a real solution. — TjerkW, Feb 10 '12 at 10:25
@TjerkW I don't think there any other solution. If your memory gets low you have to let the garbage collector clean the images — neteinstein, Feb 22 '12 at 14:37
Awesome solution Peter! The thing with the WeakReference workes like a charm, thanks! — Elias, Jan 22 '13 at 14:42

score 4 · Answer 2 · answered Nov 26 '10 at 03:34

Something that marked me in your code is that you don't recycle all your bitmaps apparently. Here are a couple of code snippets that could help:

bmp = getBitmapFromRessourceID(R.drawable.menu);
ratio = (float)this.height/(float)bmp.getScaledHeight(canvas);
temp = Bitmap.createScaledBitmap(bmp, (int)(bmp.getWidth()*ratio), (int) (bmp.getHeight()*ratio-10), false);
bmp.recycle();
bmp = temp;

and:

Bitmap temp = BitmapFactory.decodeResource(context.getResources(), resource, opts);
Bitmap bmp = Bitmap.createBitmap(temp, 0, 0, temp.getWidth(), temp.getHeight(), flip, true);
temp.recycle();

Android custom view Bitmap memory leak

2 Answers2

Linked