Building your first Android project with OpenCV

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:opencv="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.hellovisionworld.HelloVisionActivity" >
    <org.opencv.android.JavaCameraView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:visibility="gone"
        android:id="@+id/HelloVisionView"
        opencv:show_fps="true"
        opencv:camera_id="any" />
</RelativeLayout>

</application>

<uses-permission android:name="android.permission.CAMERA"/>

<uses-feature android:name="android.hardware.camera" android:required="false"/>
<uses-feature android:name="android.hardware.camera.autofocus" android:required="false"/>
<uses-feature android:name="android.hardware.camera.front" android:required="false"/>
<uses-feature android:name="android.hardware.camera.front.autofocus" android:required="false"/>

<application
    android:icon="@drawable/icon"
    android:label="@string/app_name"
    android:theme="@android:style/Theme.NoTitleBar.Fullscreen" >

adb install <OpenCV4Android SDK_Home>\apk\OpenCV_2.4.X_Manager_2.X_<platform>.apk

//A Tag to filter the log messages
private static final String  TAG = "Example::HelloVisionWorld::Activity";

//A class used to implement the interaction between OpenCV and the //device camera.
private CameraBridgeViewBase mOpenCvCameraView;

//This is the callback object used when we initialize the OpenCV //library asynchronously
private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {

    @Override
       //This is the callback method called once the OpenCV //manager is connected
    public void onManagerConnected(int status) {
      switch (status) {
  //Once the OpenCV manager is successfully connected we can enable the camera interaction with the defined OpenCV camera view
      case LoaderCallbackInterface.SUCCESS:
        {
          Log.i(TAG, "OpenCV loaded successfully");
          mOpenCvCameraView.enableView();
        } break;
          default:
            {
              super.onManagerConnected(status);
            } break;
       }
    }
};

@Override
public void onResume(){

  super.onResume();

//Call the async initialization and pass the callback object we //created later, and chose which version of OpenCV library to //load. Just make sure that the OpenCV manager you installed //supports the version you are trying to load.
  OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_10, this, mLoaderCallback);
}

public class HelloVisionActivity extends Activity implements CvCameraViewListener2

@Override
protected void onCreate(Bundle savedInstanceState) {
  Log.i(TAG, "called onCreate");

  super.onCreate(savedInstanceState);
    getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
  setContentView(R.layout.activity_hello_vision);

  mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.HelloVisionView);

  //Set the view as visible
  mOpenCvCameraView.setVisibility(SurfaceView.VISIBLE);

  //Register your activity as the callback object to handle //camera frames
  mOpenCvCameraView.setCvCameraViewListener(this);
}

public Mat onCameraFrame(CvCameraViewFrame inputFrame) {

  //We're returning the colored frame as is to be rendered on //thescreen.
  return inputFrame.rgba();
}