title: Some confusedness of BitmapFactory.Options.inBitmap
body: <p>As everyone knows, If BitmapFactory.Options.inBitmap  option is set, decode methods that take the Options object will attempt to reuse an existing bitmap when loading content.My problems are:</p>
  
  <ol>
  <li><p>how it works</p></li>
  <li><p>if I reuse an using bitmap，what will the reused bitmap happen</p></li>
  <li>If this situation will happen：Two images simultaneously on the screen，one reuse another one，then two bitmap the images used will repeat。</li>
  <li>how to use inBitmap Correctly</li>
  </ol>