title: android zoom in / out not working in custom camera appa
body: <p>I have this function to add zoom control to my camera app. This function is called from 
  surfaceChanged()</p>
  
  <p>But on many of the devices pressing + / - for zoom out / in shows no effect. These devices support Zoom . Also the code is working on sony xperia , so the code must be correct.</p>
  
  <p>Please help me to fix it. Is there anything more i need to do . </p>
  
  <pre><code>public void setZoomControl(Camera.Parameters params) {
      ZoomControls zoomControls = (ZoomControls) findViewById(R.id.CAMERA_ZOOM_CONTROLS);
  
      if (params.isZoomSupported()) {
          maxZoomLevel = params.getMaxZoom();
          Log.i("max ZOOM ", "is " + maxZoomLevel);
          ;
  
          zoomControls.setIsZoomInEnabled(true);
          zoomControls.setIsZoomOutEnabled(true);
  
          zoomControls.setOnZoomInClickListener(new OnClickListener() {
              public void onClick(View v) {
                  if (currentZoomLevel &lt; maxZoomLevel) {
                      currentZoomLevel++;
                      camera.startSmoothZoom(currentZoomLevel);
                  }
              }
          });
  
          zoomControls.setOnZoomOutClickListener(new OnClickListener() {
              public void onClick(View v) {
                  if (currentZoomLevel &gt; 0) {
                      currentZoomLevel--;
                      camera.startSmoothZoom(currentZoomLevel);
                  }
              }
          });
      } else
          zoomControls.setVisibility(View.GONE);
  }
  </code></pre>