title: Why android camera preview need a surfaceView?
body: <p>Call <strong>startPreview()</strong> to start updating the preview surface. Preview must be started before you can take a picture. Without a surface, the camera will be unable to start the preview.</p>
  
  <p>What did android api do to the surface view ? </p>
  
  <p>Why setPreviewSurface(Surface surface) must be called before startPreview() ?</p>
  
  <p>I just got the data via On data callback, not from a surface view.</p>