Issue when recycling bitmap obtained from 'BitmapDrawable'

Question

I'm loading a bitmap to use as a texture in my OpenGLES 2.0 app

If I load and use the bitmap via Bitmapfactory then all is OK. Like so:

Load

 public void loadBitmaps{

    backgrounds= BitmapFactory.decodeResource(view.getResources(), R.drawable.backgrounds, BMFOptions);
    ...

Use

//Apply as texture to OpenGL Quad

Recycle

backgrounds.recycle();

.

Now, the problem...........

.

When I load the bitmap as a bitmapDrawable, I get problems (explained below code). Like so:

.

Declare BitmapDrawable at class level

public class Res{

    BitmapDrawable bd;
    ...

Load

public void loadBitmaps(){

    bd = (BitmapDrawable) view.getResources().getDrawable(R.drawable.backgrounds);
    backgrounds = bd.getBitmap();
    ...

Use

//Apply as texture to OpenGL Quad

Recycle

backgrounds.recycle();

When doing this, it works the first time, but if I then press back to exit, and relaunch the app, the textures don't show and all I get are black quads.

If I do any of the following it solves the problem and I would like to know why......

• Either move the declaration of bd from a class variable so I'm using:

BitmapDrawable bd = (BitmapDrawable) view.getResources().getDrawable(R.drawable.backgrounds);

• Or simply do this after creating the bitmap:

bd = null;

• finally, I can also, just not recycle the bitmap, but this isn't an option

Note I need to access the bitmap in this way rather than using BitmapFactory as I'm accessing it via an XML Alias.

Answer 1

Drawable instances are cached and shared, so when you do a call to getDrawable() it will load the one it currently has cached rather than creating a new bitmap. If you recycle the underlying bitmap, that's going to cause problems with future uses. What you likely want to do is make a copy of the drawable before modifying it:

BitmapDrawable bmpDrawable = (BitmapDrawable) view.getResources()
        .getDrawable(R.drawable.backgrounds);
Bitmap original = bmpDrawable.getBitmap();
Bitmap copy = original.copy(original.getConfig(), true);

See this blog post for more info on drawable mutations.