Android如何实现裁剪照片功能

package com.jph.cp;
 
import java.io.File;
import java.io.FileNotFoundException;
import android.support.v7.app.ActionBarActivity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.view.View;
import android.widget.ImageView;
 
/**
 * 从相册选择照片进行裁剪，从相机拍取照片进行裁剪
 * @author JPH
 * Date:2014.10.09
 */
public class MainActivity extends ActionBarActivity {
    private final static int SELECT_PIC=0x123; 
    private final static int TAKE_PIC=0x124; 
    private final static int CROP_PIC=0x125; 
    private Uri imageUri;
    private ImageView imgShow;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //初始化imageUri
        imageUri=Uri.fromFile(new File(Environment.getExternalStorageDirectory(), "test.jpg"));
        imgShow=(ImageView)findViewById(R.id.imgShow);
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        // TODO Auto-generated method stub
        switch (requestCode) {
        case SELECT_PIC:
            if (resultCode==RESULT_OK) {
                try {
                    Bitmap bitmap=BitmapFactory.decodeStream(getContentResolver().
                            openInputStream(imageUri));//将imageUri对象的图片加载到内存
                    imgShow.setImageBitmap(bitmap);
                } catch (FileNotFoundException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            break;
        case TAKE_PIC:
            if (resultCode==RESULT_OK) {
                cropImageUri(imageUri, 600, 600, CROP_PIC);
            }
            break;
        case CROP_PIC:
            if (resultCode==RESULT_OK) {
                try {
                    Bitmap bitmap=BitmapFactory.decodeStream(getContentResolver().
                            openInputStream(imageUri));//将imageUri对象的图片加载到内存
                    imgShow.setImageBitmap(bitmap);
                } catch (FileNotFoundException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            break;
        default:
            break;
        }
        super.onActivityResult(requestCode, resultCode, data);
    }
    /**
     * 裁剪指定uri对应的照片
     * @param imageUri：uri对应的照片
     * @param outputX：裁剪宽
     * @param outputY：裁剪高
     * @param requestCode：请求码
     */
    private void cropImageUri(Uri imageUri, int outputX, int outputY, int requestCode){
        Intent intent = new Intent("com.android.camera.action.CROP");
        intent.setDataAndType(imageUri, "image/*");
        intent.putExtra("crop", "true");
        intent.putExtra("aspectX", 1);
        intent.putExtra("aspectY", 1);
        intent.putExtra("outputX", outputX);
        intent.putExtra("outputY", outputY);
        intent.putExtra("scale", true);
        intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
        intent.putExtra("return-data", false);
        intent.putExtra("outputFormat", Bitmap.CompressFormat.JPEG.toString());
        intent.putExtra("noFaceDetection", true); // no face detection
        startActivityForResult(intent, requestCode);
    }
 
    public void cropPic(View view) {
        switch (view.getId()) {
        case R.id.btnCropFromGallery://从相册选择照片进行裁剪
            cropFromGallery();
            break;
        case R.id.btnCropFromTake://从相机拍取照片进行裁剪
            cropFromTake();
            break;
 
        default:
            break;
        }
    }
    /**
     * 从相机拍取照片进行裁剪
     */
    private void cropFromTake() {
        // TODO Auto-generated method stub
        Intent intent=new Intent();
        intent.setAction(MediaStore.ACTION_IMAGE_CAPTURE);//设置Action为拍照
        intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);//将拍取的照片保存到指定URI
        startActivityForResult(intent, TAKE_PIC);
    }
    /**
     * 从相册选择照片进行裁剪
     */
    private void cropFromGallery() {
        // TODO Auto-generated method stub        
        Intent intent=new Intent();
        intent.setAction(Intent.ACTION_PICK);//Pick an item from the data
        intent.setType("image/*");//从所有图片中进行选择
        intent.putExtra("crop", "true");//设置为裁切
        intent.putExtra("aspectX", 1);//裁切的宽比例
        intent.putExtra("aspectY", 1);//裁切的高比例
        intent.putExtra("outputX", 600);//裁切的宽度
        intent.putExtra("outputY", 600);//裁切的高度
        intent.putExtra("scale", true);//支持缩放
        intent.putExtra("return-data", false);
        intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);//将裁切的结果输出到指定的Uri
        intent.putExtra("outputFormat", Bitmap.CompressFormat.JPEG.toString());//裁切成的图片的格式
        intent.putExtra("noFaceDetection", true); // no face detection
        startActivityForResult(intent, SELECT_PIC);    
    }
}