Android 2.1 View's getDrawingCache() method always returns null

Question

Hello,

I'm working with Android 2.1 and have the following problem: Using the method View.getDrawingCache() always returns null. getDrawingCache() should return a Bitmap, which is the presentation of View's content.

Example code:

public void onCreate(final Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);

  setContentView(R.layout.main);

  final View view = findViewById(R.id.ImageView01);
  view.setDrawingCacheEnabled(true);
  view.buildDrawingCache();
  final Bitmap bmp = view.getDrawingCache();
  System.out.println(bmp);

}

I've already tried different ways to configure the View object for generating the drawing cache (e.g. View.setWillNotDraw(boolean) and View.setWillNotCacheDrawing(boolean)), but nothing works.

What is the right way, or what I'm doing wrong?

PS: In real code I want to apply getDrawingCache() on a ViewGroup like RelativeLayout. Is the behaviour the same when using a ViewGroup?

Answer 1

As far as I read the last days in the documentation you should onlycall setDrawingCacheEnabled or buildDrawingChache() but not both.

Answer 2

use

onLayout(x, y, width, height);

for ex:

onLayout(0, 0, 100, 100);

before calling getDrawingCache