gistfile1.java

@Override
protected void onStop() {

	// Release memory held by background bitmaps
	AndroidUtils.releaseBackgroundImageMemory(root);
	AndroidUtils.releaseBackgroundImageMemory(decorFrame);

	super.onStop();
}

gistfile2.java

/**
 * Releases memory held by a view's background image.
 * <p>
 * On Android 4.2 you'll also need to turn off hardware acceleration else the memory won't be released. Instead of
 * Bitmaps you'll just end up with GLES20DisplayList instances consuming the exact same amount of memory.
 */
@SuppressWarnings("deprecation")
public static void releaseBackgroundImageMemory(View v) {
	final Drawable d = v.getBackground();

	if (d != null) {
		d.setCallback(null);

		if (d instanceof BitmapDrawable) {
			BitmapDrawable b = (BitmapDrawable) d;
			Bitmap bitmap = b.getBitmap();
			if (bitmap != null) {
				bitmap.recycle();
			}
		}
	}

	v.setBackgroundDrawable(null);
}