<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    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"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="com.whieenz.myapplication.MainActivity"
    tools:showIn="@layout/activity_main"
    android:orientation="vertical">

    <ImageView
        android:layout_width="match_parent"
        android:layout_height="450dp"
        android:id="@+id/image"
        android:src="@drawable/genie" />
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="灰度化"
        android:id="@+id/button" />
</LinearLayout>

package com.whieenz.myapplication;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
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.OpenCVLoader;
import org.opencv.android.Utils;
import org.opencv.core.Mat;
import org.opencv.imgproc.Imgproc;

public class MainActivity extends Activity {

    private ImageView imageView;
    private Button button;
    private Bitmap srcBitmap;
    private Bitmap grayBitmap;
    private static boolean flag = true;
    private static boolean isFirst = true;
    private static final String TAG = "gao_chun";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.content_main);

        imageView = (ImageView)findViewById(R.id.image);
        button = (Button)findViewById(R.id.button);
        button.setOnClickListener(new MyOnClickListener()) ;

    }

    public class MyOnClickListener implements View.OnClickListener{
        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            if(isFirst){
                procSrc2Gray();
                isFirst = false;
            }
            if(flag){
                imageView.setImageBitmap(grayBitmap);
                button.setText("查看原图");
                flag = false;
            }else{
                imageView.setImageBitmap(srcBitmap);
                button.setText("灰度化");
                flag = true;
            }
        }
    }



    @Override
    protected void onResume() {
        super.onResume();
        OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_9,getApplicationContext(),mLoaderCallback);
    }

    private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {
            @Override
        public void onManagerConnected(int status) {
            super.onManagerConnected(status);
            switch (status){
                case BaseLoaderCallback.SUCCESS:
                    Log.i(TAG, "成功加载");
                    break;
                default:
                    super.onManagerConnected(status);
                    Log.i(TAG, "加载失败");
                    break;
            }

        }
    };

    public void procSrc2Gray(){
        Mat rgbMat = new Mat();
        Mat grayMat = new Mat();
        srcBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.genie);
        grayBitmap = Bitmap.createBitmap(srcBitmap.getWidth(), srcBitmap.getHeight(), Bitmap.Config.RGB_565);
        Utils.bitmapToMat(srcBitmap, rgbMat);//convert original bitmap to Mat, R G B.
        Imgproc.cvtColor(rgbMat, grayMat, Imgproc.COLOR_RGB2GRAY);//rgbMat to gray grayMat
        Utils.matToBitmap(grayMat, grayBitmap); //convert mat to bitmap
        Log.i(TAG, "procSrc2Gray sucess...");
    }
}