拍照后如何得到真实大小的图片

public class MainActivity extends Activity {        Button mButton;       private static int REQ_2 = 2;    private String mFilePath;    ImageView mImageView;    FileInputStream fileInputStream;// 输入流    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        mButton = (Button) findViewById(R.id.btnCamera);        mImageView = (ImageView) findViewById(R.id.ivView);        mFilePath = Environment.getExternalStorageDirectory().getPath();        mFilePath = mFilePath+"/"+"temp.png";    }    pubilc void cameraClick1(View view){        Intent it = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);        Uri potho = Uri.fromFile(new File(mFilePath));//指定目录        it.putExtra(MediaStore.EXTRA_OUTPUT,potho);//把系统获取到的图片放到指定的目录下        startActivityForResult(it, REQ_2);    }    @Override    protected void onActivityResult(int requestCode, int resultCode, Intent data) {        super.onActivityResult(requestCode, resultCode, data);        if(resultCode==RESULT_OK&&requestCode == REQ_1){           Bundle build = data.getExtras();            Bitmap bitmap = (Bitmap)build.get("data");            mImageView.setImageBitmap(bitmap);        }else  if(resultCode==RESULT_OK&&requestCode == REQ_2){            try {                 fileInputStream = new FileInputStream(mFilePath);                Bitmap bitmap = BitmapFactory.decodeStream(fileInputStream);                mImageView.setImageBitmap(bitmap);            } catch (FileNotFoundException e) {                e.printStackTrace();            }finally {                try {                    fileInputStream.close();                } catch (IOException e) {                    e.printStackTrace();                }            }        }    }}