camera view was enabled to visible when the app launched

samples/android/color-blob-detection/src/org/opencv/samples/colorblobdetect/ColorBlobDetectionActivity.java

@@ -73,6 +73,7 @@ public class ColorBlobDetectionActivity extends Activity implements OnTouchListe
         setContentView(R.layout.color_blob_detection_surface_view);
 
         mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.color_blob_detection_activity_surface_view);
+		  mOpenCvCameraView.setVisibility(SurfaceView.VISIBLE);
         mOpenCvCameraView.setCvCameraViewListener(this);
     }