Recycle ImageView's Bitmap

Question

I have something like this:

Bitmap.Config conf = Bitmap.Config.ARGB_8888;
WeakReference bm = new WeakReference(Bitmap.createBitma         


        

Answer 1

Don't create images larger than you need at any one time. The heap limitations are designed to prevent you from hanging yourself and completely taking over the device's limited memory.

If you need more detail because you plan on zooming in, then re-render that portion of the image with higher detail at zoom time, excluding the portions you aren't viewing.

Answer 2

In your onDestroy method you could try something like this:

ImageView imageView = (ImageView)findViewById(R.id.my_image);
Drawable drawable = imageView.getDrawable();
if (drawable instanceof BitmapDrawable) {
    BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable;
    Bitmap bitmap = bitmapDrawable.getBitmap();
    bitmap.recycle();
}

The cast should work since setImageBitmap is implemented as

public void setImageBitmap(Bitmap bm) {
    setImageDrawable(new BitmapDrawable(mContext.getResources(), bm));
}

Answer 3

Devconsole's answer is great, but you can also store all bitmap objects in list like member of your class, and then recycle them in cycle when the onDestroy() method of activity (or some other release lifecycle method of component where you use bitmap) will be called.

Answer 4

If you set the same bitmap object on all your ImageViews, it shouldn't throw an OutOfMemoryError. Basically, this should work:

WeakReference<Bitmap> bm = new WeakReference<Bitmap>(Bitmap.createBitmap(3000 + 3000, 2000, Bitmap.Config.ARGB_8888));

Canvas canvas = new Canvas(bm.get());
canvas.drawBitmap(firstBitmap, 0, 0, null);
canvas.drawBitmap(bm, firstBitmap.getWidth(), 0, null);

imageView1.setImageBitmap(bm.get());
imageView2.setImageBitmap(bm.get());
imageView3.setImageBitmap(bm.get());
imageView4.setImageBitmap(bm.get());
imageView5.setImageBitmap(bm.get());
// ...

If this doesn't work, it simply means your bitmap is too large (6000x2000 pixels is about 12 megabytes, if I calculated right). You can either:

• make your bitmap smaller
• cut down on other stuff that use a lot of memory