我的要求是，我必须建立一个使用Android JAVA的视频录制应用程序，其中用户将保存他的30秒的视频将被发送到另一个服务器。用户将使用视频录制只有一次。
我只是想让用户看到计时器从0到30秒开始，所以当他按下开始记录按钮后。
我该怎么做呢？请帮助我。下面分享我的代码。

public class VideoKycActivity extends AppCompatActivity implements ImageAnalysis.Analyzer, View.OnClickListener {
        private ListenableFuture<ProcessCameraProvider> cameraProviderFuture;

    PreviewView previewView;
    private VideoCapture videoCapture;
    private Button bRecord;

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

        previewView = findViewById(R.id.previewView);
        bRecord = findViewById(R.id.bRecord);
        bRecord.setText("start recording"); // Set the initial text of the button
        
        bRecord.setOnClickListener(this);

        cameraProviderFuture = ProcessCameraProvider.getInstance(this);
        cameraProviderFuture.addListener(() -> {
            try {
                ProcessCameraProvider cameraProvider = cameraProviderFuture.get();
                startCameraX(cameraProvider);
            } catch (ExecutionException | InterruptedException e) {
                e.printStackTrace();
            }
        }, getExecutor());

    }

    Executor getExecutor() {
        return ContextCompat.getMainExecutor(this);
    }

    @SuppressLint("RestrictedApi")
    private void startCameraX(ProcessCameraProvider cameraProvider) {
        cameraProvider.unbindAll();
        CameraSelector cameraSelector = new CameraSelector.Builder()
                .requireLensFacing(CameraSelector.LENS_FACING_BACK)
                .build();
        Preview preview = new Preview.Builder()
                .build();
        preview.setSurfaceProvider(previewView.getSurfaceProvider());

        // Video capture use case
        videoCapture = new VideoCapture.Builder()
                .setVideoFrameRate(30)
                .build();

        // Image analysis use case
        ImageAnalysis imageAnalysis = new ImageAnalysis.Builder()
                .setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
                .build();

        imageAnalysis.setAnalyzer(getExecutor(), this);

        //bind to lifecycle:
        cameraProvider.bindToLifecycle((LifecycleOwner) this, cameraSelector, preview, videoCapture);

    }

    @Override
    public void analyze(@NonNull ImageProxy image) {
        // image processing here for the current frame
        Log.d("TAG", "analyze: got the frame at: " + image.getImageInfo().getTimestamp());
        image.close();
    }

    @SuppressLint("RestrictedApi")
    @Override
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.bRecord:
                if (bRecord.getText() == "start recording"){
                    bRecord.setText("stop recording");
                    recordVideo();
                } else {
                    bRecord.setText("start recording");
                    videoCapture.stopRecording();
                }
                break;

        }
    }

    @SuppressLint("RestrictedApi")
    private void recordVideo() {
        if (videoCapture != null) {

            long timestamp = System.currentTimeMillis();

            ContentValues contentValues = new ContentValues();
            contentValues.put(MediaStore.MediaColumns.DISPLAY_NAME, timestamp);
            contentValues.put(MediaStore.MediaColumns.MIME_TYPE, "video/mp4");

            try {
                if (ActivityCompat.checkSelfPermission(this, Manifest.permission.RECORD_AUDIO) != PackageManager.PERMISSION_GRANTED) {
                    // TODO: Consider calling
                    //    ActivityCompat#requestPermissions
                    // here to request the missing permissions, and then overriding
                    //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
                    //                                          int[] grantResults)
                    // to handle the case where the user grants the permission. See the documentation
                    // for ActivityCompat#requestPermissions for more details.
                    return;
                }
                videoCapture.startRecording(
                        new VideoCapture.OutputFileOptions.Builder(
                                getContentResolver(),
                                MediaStore.Video.Media.EXTERNAL_CONTENT_URI,
                                contentValues
                        ).build(),
                        getExecutor(),
                        new VideoCapture.OnVideoSavedCallback() {
                            @Override
                            public void onVideoSaved(@NonNull VideoCapture.OutputFileResults outputFileResults) {
                                Toast.makeText(VideoKycActivity.this, "Video has been saved successfully.", Toast.LENGTH_SHORT).show();
                            }

                            @Override
                            public void onError(int videoCaptureError, @NonNull String message, @Nullable Throwable cause) {
                                Toast.makeText(VideoKycActivity.this, "Error saving video: " + message, Toast.LENGTH_SHORT).show();
                            }
                        }
                );
            } catch (Exception e) {
                e.printStackTrace();
            }

        }
    }
}