【Android】显示彩色转灰度图片

package com.duanjiwei.followopencv1;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
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 AppCompatActivity {

private Button btn;
private ImageView img;

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.activity_main);

img = (ImageView)findViewById(R.id.img);
btn = (Button)findViewById(R.id.btn);
btn.setOnClickListener(new ProcessClickListener());
}

@Override
protected void onResume() {
super.onResume();
//load OpenCV engine and init OpenCV library
OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_9, getApplicationContext(), mLoaderCallback);
Log.i(TAG, "onResume sucess load OpenCV...");
}

//OpenCV库加载并初始化成功后的回调函数
private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {

@Override
public void onManagerConnected(int status) {
// TODO Auto-generated method stub
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...");
}

public class ProcessClickListener implements View.OnClickListener{

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