如何在录制的视频中显示当前时间？(android)

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <SurfaceView
        android:id="@+id/surfaceView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <TextView
        android:id="@+id/timestampTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="16sp"
        android:textColor="#FFFFFF"
        android:padding="8dp"
        android:background="#80000000"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true" />

</RelativeLayout>

public class MainActivity extends AppCompatActivity {

    private SurfaceView surfaceView;
    private TextView timestampTextView;
    private MediaRecorder mediaRecorder;
    private boolean isRecording = false;

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

        surfaceView = findViewById(R.id.surfaceView);
        timestampTextView = findViewById(R.id.timestampTextView);

        // 初始化MediaRecorder
        mediaRecorder = new MediaRecorder();
        mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        mediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
        // 设置视频输出格式、编码器等参数
        // ...

        // 开始录制按钮点击事件
        findViewById(R.id.startButton).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!isRecording) {
                    startRecording();
                } else {
                    stopRecording();
                }
            }
        });
    }

    private void startRecording() {
        try {
            // 设置输出文件路径等参数
            // ...

            // 准备MediaRecorder
            mediaRecorder.setPreviewDisplay(surfaceView.getHolder().getSurface());
            mediaRecorder.prepare();
            mediaRecorder.start();

            // 开始更新时间戳
            isRecording = true;
            updateTimestamp();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private void stopRecording() {
        try {
            // 停止录制
            mediaRecorder.stop();
            mediaRecorder.reset();
            mediaRecorder.release();

            // 停止更新时间戳
            isRecording = false;
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private void updateTimestamp() {
        if (isRecording) {
            timestampTextView.setText(getCurrentTimestamp());
            timestampTextView.postDelayed(new Runnable() {
                @Override
                public void run() {
                    updateTimestamp();
                }
            }, 1000); // 每秒更新一次时间戳
        }
    }

    private String getCurrentTimestamp() {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.getDefault());
        return sdf.format(new Date());
    }
}