依据Uri加载相册中图片

//为什么使用getContentResolver呢？因为在相册本身是一个内容提供者
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    	super.onActivityResult(requestCode, resultCode, data);
    		Uri photoFileUri=data.getData();
			if (requestCode==OK) {
				try {
					Bitmap bitmap=BitmapFactory.decodeStream
					(getContentResolver().openInputStream(photoFileUri));
				} catch (Exception e) {
					e.printStackTrace();
				}
		}
    }