title: How to destroy a drawable inside an ImageView if we don't need it?
body: <p>This question is related with <a href="https://stackoverflow.com/questions/12533001/do-we-have-to-explicitly-recycle-the-bitmap-if-we-dont-need-it">Do we have to explicitly recycle the bitmap if we don&#39;t need it?</a>.</p>
  
  <p>There is an ImageView have a drawable, when user clicks a button, it will assign a new drawable to the ImageView.</p>
  
  <p>Do we have to destroy the old drawable belongs to the ImageView, and how?</p>
  
  <pre><code>Drawable oriDrawable = imageView.getDrawable()
  
  // set callback to null
  oriDrawable.setCallback(null);
  
  // get the bitmap and recycle it
  ((BitmapDrawable)oriDrawable).getBitmap().recycle();
  </code></pre>
  
  <p>Is the code above correct? What's the best solution?</p>