title: How to clean or refresh ImageView bitMap canvas?
body: <p>The source code:</p>
  
  <pre><code>//The drawing of the circle on the canvas
  imageView = new ImageView(this);
  bitmap = Bitmap.createBitmap(200 ,200 , Bitmap.Config.ARGB_8888);
  imageView.setBackgroundDrawable(new BitmapDrawable(bitmap));
  Canvas canvas = new Canvas (bitmap);
  canvas.drawCircle (50 , 50 , 20 , paint );
  
  .....
  </code></pre>
  
  <p>Now I want to refresh or to clean the canvas</p>
  
  <p>How can I do it?</p>