android图像变为黑白

package com.example.clolorfultoblackwhite;import java.io.FileNotFoundException;import java.io.IOException;import android.app.Activity;import android.content.ContentResolver;import android.content.Intent;import android.graphics.Bitmap;import android.graphics.Bitmap.Config;import android.media.ThumbnailUtils;import android.net.Uri;import android.os.Bundle;import android.provider.MediaStore;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.ImageView;import android.widget.Toast;public class MainActivity extends Activity {private Button add;private ImageView img;private String IMAGE_TYPE = "image/*";private int PHOTO = 0;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);add = (Button) findViewById(R.id.button1);img = (ImageView) findViewById(R.id.imageView1);add.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO 自动生成的方法存根Intent intent = new Intent(Intent.ACTION_GET_CONTENT);intent.setType(IMAGE_TYPE);startActivityForResult(intent, PHOTO);}});}// /onCreate@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) {// TODO 自动生成的方法存根// /super.onActivityResult(requestCode, resultCode, data);if (resultCode != RESULT_OK) {Toast.makeText(MainActivity.this, "返回的结果出错", Toast.LENGTH_SHORT).show();return;}Bitmap bm = null;ContentResolver resolver = getContentResolver();if (requestCode == PHOTO) {Uri originalUri = data.getData();try {bm = MediaStore.Images.Media.getBitmap(resolver, originalUri);bm = convertBlackWhite(bm);img.setImageBitmap(bm);} catch (FileNotFoundException e) {// TODO 自动生成的 catch 块e.printStackTrace();} catch (IOException e) {// TODO 自动生成的 catch 块e.printStackTrace();}}}// /onActivityResultprivate Bitmap convertBlackWhite(Bitmap bmp) {// TODO 自动生成的方法存根int width = bmp.getWidth();int height = bmp.getHeight();int[] pixels = new int[width * height];bmp.getPixels(pixels, 0, width, 0, 0, width, height);int alpha = 0xFF << 24;for (int i = 0; i < height; i++) {for (int j = 0; j < width; j++) {int grey = pixels[width * i + j];// 分离三原色int red = ((grey & 0x00FF0000) >> 16);int green = ((grey & 0x0000FF00) >> 8);int blue = (grey & 0x000000FF);// 转化成灰度像素grey = (int) (red * 0.3 + green * 0.59 + blue * 0.11);grey = alpha | (grey << 16) | (grey << 8) | grey;pixels[width * i + j] = grey;}}// 新建图片Bitmap newbmp = Bitmap.createBitmap(width, height, Config.ARGB_8888);newbmp.setPixels(pixels, 0, width, 0, 0, width, height);Bitmap resizeBmp = ThumbnailUtils.extractThumbnail(newbmp, width,height);return resizeBmp;}}
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