content: package org.opencv.samples.tutorial1;
  
  import org.opencv.android.BaseLoaderCallback;
  import org.opencv.android.CameraActivity;
  import org.opencv.android.CameraBridgeViewBase.CvCameraViewFrame;
  import org.opencv.android.LoaderCallbackInterface;
  import org.opencv.android.OpenCVLoader;
  import org.opencv.core.Mat;
  import org.opencv.android.CameraBridgeViewBase;
  import org.opencv.android.CameraBridgeViewBase.CvCameraViewListener2;
  
  import android.os.Bundle;
  import android.util.Log;
  import android.view.MenuItem;
  import android.view.SurfaceView;
  import android.view.WindowManager;
  
  import java.util.Collections;
  import java.util.List;
  
  public class Tutorial1Activity extends CameraActivity implements CvCameraViewListener2 {
      private static final String TAG = "OCVSample::Activity";
  
      private CameraBridgeViewBase mOpenCvCameraView;
      private boolean              mIsJavaCamera = true;
      private MenuItem             mItemSwitchCamera = null;
  
      private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {
          @Override
          public void onManagerConnected(int status) {
              switch (status) {
                  case LoaderCallbackInterface.SUCCESS:
                  {
                      Log.i(TAG, "OpenCV loaded successfully");
                      mOpenCvCameraView.enableView();
                  } break;
                  default:
                  {
                      super.onManagerConnected(status);
                  } break;
              }
          }
      };
  
      public Tutorial1Activity() {
          Log.i(TAG, "Instantiated new " + this.getClass());
      }
  
      /** Called when the activity is first created. */
      @Override
      public void onCreate(Bundle savedInstanceState) {
          Log.i(TAG, "called onCreate");
          super.onCreate(savedInstanceState);
          getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
  
          setContentView(R.layout.tutorial1_surface_view);
  
          mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.tutorial1_activity_java_surface_view);
  
          mOpenCvCameraView.setVisibility(SurfaceView.VISIBLE);
  
          mOpenCvCameraView.setCvCameraViewListener(this);
      }
  
      @Override
      public void onPause()
      {
          super.onPause();
          if (mOpenCvCameraView != null)
              mOpenCvCameraView.disableView();
      }
  
      @Override
      public void onResume()
      {
          super.onResume();
          if (!OpenCVLoader.initDebug()) {
              Log.d(TAG, "Internal OpenCV library not found. Using OpenCV Manager for initialization");
              OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_3_0_0, this, mLoaderCallback);
          } else {
              Log.d(TAG, "OpenCV library found inside package. Using it!");
              mLoaderCallback.onManagerConnected(LoaderCallbackInterface.SUCCESS);
          }
      }
  
      @Override
      protected List<? extends CameraBridgeViewBase> getCameraViewList() {
          return Collections.singletonList(mOpenCvCameraView);
      }
  
      public void onDestroy() {
          super.onDestroy();
          if (mOpenCvCameraView != null)
              mOpenCvCameraView.disableView();
      }
  
      public void onCameraViewStarted(int width, int height) {
      }
  
      public void onCameraViewStopped() {
      }
  
      public Mat onCameraFrame(CvCameraViewFrame inputFrame) {
          return inputFrame.rgba();
      }
  }
  