title: Get the rotate value from matrix in android?
body: <p>How to the rotate value from a translated/scaled/rotated matrix?</p>
  
  <pre><code>Matrix matrix = new Matrix();
  matrix.postScale(...);
  matrix.postTranslate(...);
  matrix.postRotate(...);
  ...
  </code></pre>
  
  <p>Now I don't know what the <code>rotate</code> it was, but I need to get it. How to do this?</p>