在真实设备上，使用MediaProjection截屏时，需要请求用户允许截屏的权限。以下是一个示例：

首先，在AndroidManifest.xml文件中添加以下权限：

然后，创建一个类来请求屏幕截图权限：

public class ScreenCaptureRequester { private static final String TAG = "ScreenCaptureRequester"; private static final int REQUEST_CODE = 1;

private Activity mActivity;
private MediaProjectionManager mProjectionManager;
private OnScreenCapturePermissionListener mListener;

public ScreenCaptureRequester(Activity activity) {
    mActivity = activity;
    mProjectionManager = (MediaProjectionManager) mActivity.getSystemService(Context.MEDIA_PROJECTION_SERVICE);
}

public void requestPermission(OnScreenCapturePermissionListener listener) {
    mListener = listener;
    mActivity.startActivityForResult(mProjectionManager.createScreenCaptureIntent(), REQUEST_CODE);
}

public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == REQUEST_CODE) {
        if (resultCode == Activity.RESULT_OK) {
            MediaProjection mediaProjection = mProjectionManager.getMediaProjection(resultCode, data);
            mListener.onScreenCapturePermissionGranted(mediaProjection);
        } else {
            mListener.onScreenCapturePermissionDenied();
        }
    }
}

public interface OnScreenCapturePermissionListener {
    void onScreenCapturePermissionGranted(MediaProjection mediaProjection);
    void onScreenCapturePermissionDenied();
}

}

通过上述代码，可以请求屏幕截图权限并接收结果。在返回结果时，可以根据用户的处理结果选择相应的操作。

例如，在MainActivity类中使用该实例：

public class MainActivity extends AppCompatActivity implements ScreenCaptureRequester.OnScreenCapturePermissionListener { private static final String TAG = "MainActivity";

private ScreenCaptureRequester mScreenCaptureRequester;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mScreenCaptureRequester = new ScreenCaptureRequester(this);
    mScreenCaptureRequester.requestPermission(this);
}

@Override
public void onScreenCapturePermission