Use OpenCv for taking image and showing in ImageView

gistfile1.txt

package com.apps.facedetect;

import android.Manifest;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.os.Build;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

import org.opencv.android.BaseLoaderCallback;
import org.opencv.android.CameraBridgeViewBase;
import org.opencv.android.LoaderCallbackInterface;
import org.opencv.android.OpenCVLoader;
import org.opencv.android.Utils;
import org.opencv.core.CvType;
import org.opencv.core.Mat;

public class SegmentActivity extends AppCompatActivity  implements CameraBridgeViewBase.CvCameraViewListener2{

    private static final int CAMERA_PERMISSION_REQUEST_CODE =1 ;
    private static final String TAG = MainActivity.class.getSimpleName();
    CameraBridgeViewBase cameraBridgeViewBase;
    ImageView faceDetectionImageView;
    Mat mat;
    Button analyseBtn;
    Bitmap mBitmap;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_segment);
        checkCameraPermission();

        analyseBtn = (Button) findViewById(R.id.analyseBtn);
        analyseBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                // convert to bitmap:
                mBitmap = Bitmap.createBitmap(mat.cols(), mat.rows(),Bitmap.Config.ARGB_8888);
                Utils.matToBitmap(mat, mBitmap);

                // find the imageview and draw it!
                faceDetectionImageView.setImageBitmap(mBitmap);

                faceDetectionImageView.setVisibility(View.VISIBLE);
                cameraBridgeViewBase.setVisibility(View.GONE);

            }
        });
    }

    private void checkCameraPermission() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (checkSelfPermission(Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
                requestPermissions(new String[] {Manifest.permission.CAMERA}, CAMERA_PERMISSION_REQUEST_CODE);
            }else {
                Log.i(TAG,"Ready to Proceed");
                proceedFurther();
            }
        }
    }


    private void proceedFurther() {
        faceDetectionImageView = (ImageView) findViewById(R.id.faceDetectionImageView);
        cameraBridgeViewBase = (CameraBridgeViewBase) findViewById(R.id.faceDetectionJavaCameraView);
        cameraBridgeViewBase.setVisibility(CameraBridgeViewBase.VISIBLE);;
        cameraBridgeViewBase.setCvCameraViewListener(this);

        if (!OpenCVLoader.initDebug()){
            Log.d(TAG, "Internal OpenCv library found,Using OpenCV Manager for initialization ");
            OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_3_2_0,this,baseLoaderCallback);
        }else {
            Log.d(TAG, "OpenCV library found inside package. Using it!");
            baseLoaderCallback.onManagerConnected(LoaderCallbackInterface.SUCCESS);
        }
    }


    BaseLoaderCallback baseLoaderCallback = new BaseLoaderCallback(this) {
        @Override
        public void onManagerConnected(int status) {
            switch (status){
                case LoaderCallbackInterface.SUCCESS:{
                    Log.i(TAG, "OpenCV loaded successfully");
                    cameraBridgeViewBase.enableView();

                }

                break;
                default:
                    super.onManagerConnected(status);
                    break;
            }

        }
    };


    @Override
    public void onCameraViewStarted(int width, int height) {
        mat = new Mat(height,width, CvType.CV_8UC4);
    }

    @Override
    public void onCameraViewStopped() {
        mat.release();
    }

    @Override
    public Mat onCameraFrame(CameraBridgeViewBase.CvCameraViewFrame inputFrame) {

        mat = inputFrame.rgba();
        return mat;
    }


}