public static final int TAKE_PHOTO = 1; 
public static final int CROP_PHOTO = 2; 
public static final int ACTION_CHOOSE=3; 
private Uri imageUri; //图片路径 
private String filename; //图片名称 

@Override 
  public void onClick(View v) { 
    switch (v.getId()) { 
      case R.id.bt1:  //拍照截取 
        SimpleDateFormat format = new SimpleDateFormat("yyyyMMddHHmmss"); 
        Date date = new Date(System.currentTimeMillis()); 
        filename = format.format(date); 
        File path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM); 
        File outputImage = new File(path, filename +".jpg"); 
        try { 
          if (outputImage.exists()) { 
            outputImage.delete(); 
          } 
          outputImage.createNewFile(); 
        } catch (IOException e) { 
          e.printStackTrace(); 
        } 
        //将File对象转换为Uri并启动照相程序 
        imageUri = Uri.fromFile(outputImage); 
        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); //照相 
        intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri); //指定图片输出地址 
        startActivityForResult(intent, TAKE_PHOTO); //启动照相 
        break; 
      case R.id.bt2:  //相册选取 
        Intent intent2 = new Intent(Intent.ACTION_PICK); 
        intent2.setDataAndType(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,"image/*"); 
        startActivityForResult(intent2,ACTION_CHOOSE); 
        break; 
    } 
  } 

// 使用startActivityForResult返回结果时调用的方法 
  @Override 
  protected void onActivityResult(int requestCode, int resultCode, Intent data) { 
    super.onActivityResult(requestCode, resultCode, data); 
    if(resultCode!=RESULT_OK){ 
      Toast.makeText(this, "取消了", Toast.LENGTH_SHORT).show(); 
      return; 
    } 
    switch (requestCode) { 
      case TAKE_PHOTO:  //拍照的回调 
        cropImage(); 
        break; 
      case ACTION_CHOOSE:  //选择照片的回调 
        imageUri = data.getData(); 
        cropImage(); 
        break; 
      case CROP_PHOTO:  //裁剪完照片的回调 
        showPic(); 
        break; 
      default: 
        break; 
    } 
  } 

/** 
 * 裁剪图片 
 **/ 
private void cropImage() { 
  Intent intent = new Intent("com.android.camera.action.CROP"); //剪裁 
  intent.setDataAndType(imageUri, "image/*"); 
  intent.putExtra("scale", true); 
  //设置宽高比例 
  intent.putExtra("aspectX", 1); 
  intent.putExtra("aspectY", 1); 
  //设置裁剪图片宽高 
  intent.putExtra("outputX", 340); 
  intent.putExtra("outputY", 340); 
  intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri); 
  Toast.makeText(MainActivity.this, "剪裁图片", Toast.LENGTH_SHORT).show(); 
  //广播刷新相册 
  Intent intentBc = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE); 
  intentBc.setData(imageUri); 
  this.sendBroadcast(intentBc); 
  startActivityForResult(intent, CROP_PHOTO); //设置裁剪参数显示图片至ImageView 
}