自定义视频录制屏幕

我正在尝试实现一个应用程序，该应用程序在启动时使用我的自定义视频录制屏幕自动开始视频录制，并使用我自己的按钮来停止录制和其他按钮。到目前为止，我所做的是设计带有按钮的布局，但如何在后台添加视频录制屏幕..请帮忙。！

这就是我实现它的方法：

public class MainActivity extends Activity implements SurfaceHolder.Callback {
    private MediaRecorder recorder;
    private SurfaceHolder surfaceHolder;
    private CamcorderProfile camcorderProfile;
    private Camera camera;
    boolean recording = false;
    boolean usecamera = true;
    boolean previewRunning = false;
    SurfaceView surfaceView;
    Button btnStart, btnStop;
    File root;
    File file;
    Boolean isSDPresent;
    SimpleDateFormat simpleDateFormat;
    String timeStamp;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
        setContentView(R.layout.activity_main);
        initComs();
        actionListener();
    }

    private void initComs() {
        simpleDateFormat = new SimpleDateFormat("ddMMyyyyhhmmss");
        timeStamp = simpleDateFormat.format(new Date());
        camcorderProfile = CamcorderProfile.get(CamcorderProfile.QUALITY_HIGH);
        surfaceView = (SurfaceView) findViewById(R.id.preview);
        surfaceHolder = surfaceView.getHolder();
        surfaceHolder.addCallback(this);
        btnStop = (Button) findViewById(R.id.btn_stop);
        surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        isSDPresent = android.os.Environment.getExternalStorageState().equals(
                android.os.Environment.MEDIA_MOUNTED);

    }

    public static float megabytesAvailable(File f) {
        StatFs stat = new StatFs(f.getPath());
        long bytesAvailable = (long) stat.getBlockSize()
                * (long) stat.getAvailableBlocks();
        return bytesAvailable / (1024.f * 1024.f);
    }



    private void actionListener() {
        btnStop.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                if (recording) {
                    recorder.stop();
                    if (usecamera) {
                        try {
                            camera.reconnect();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                    // recorder.release();
                    recording = false;
                    // Let's prepareRecorder so we can record again
                    prepareRecorder();
                }

            }
        });
    }

    private void prepareRecorder() {
        recorder = new MediaRecorder();
        recorder.setPreviewDisplay(surfaceHolder.getSurface());
        if (usecamera) {
            camera.unlock();
            recorder.setCamera(camera);
        }
        recorder.setAudioSource(MediaRecorder.AudioSource.DEFAULT);
        recorder.setVideoSource(MediaRecorder.VideoSource.DEFAULT);

        recorder.setProfile(camcorderProfile);

        if (camcorderProfile.fileFormat == MediaRecorder.OutputFormat.MPEG_4) {
            recorder.setOutputFile("/sdcard/XYZApp/" + "XYZAppVideo" + ""
                    + new SimpleDateFormat("ddMMyyyyHHmmss").format(new Date())
                    + ".mp4");
        } else if (camcorderProfile.fileFormat == MediaRecorder.OutputFormat.MPEG_4) {
            recorder.setOutputFile("/sdcard/XYZApp/" + "XYZAppVideo" + ""
                    + new SimpleDateFormat("ddMMyyyyHHmmss").format(new Date())
                    + ".mp4");
        } else {
            recorder.setOutputFile("/sdcard/XYZApp/" + "XYZAppVideo" + ""
                    + new SimpleDateFormat("ddMMyyyyHHmmss").format(new Date())
                    + ".mp4");
        }

        try {
            recorder.prepare();
        } catch (IllegalStateException e) {
            e.printStackTrace();
            finish();
        } catch (IOException e) {
            e.printStackTrace();
            finish();
        }
    }

    public void surfaceCreated(SurfaceHolder holder) {
        System.out.println("onsurfacecreated");

        if (usecamera) {
            camera = Camera.open();

            try {
                camera.setPreviewDisplay(holder);
                camera.startPreview();
                previewRunning = true;
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }

    public void surfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {
        System.out.println("onsurface changed");

        if (!recording && usecamera) {
            if (previewRunning) {
                camera.stopPreview();
            }

            try {
                Camera.Parameters p = camera.getParameters();

                p.setPreviewSize(camcorderProfile.videoFrameWidth,
                        camcorderProfile.videoFrameHeight);
                p.setPreviewFrameRate(camcorderProfile.videoFrameRate);

                camera.setParameters(p);

                camera.setPreviewDisplay(holder);
                camera.startPreview();
                previewRunning = true;
            } catch (IOException e) {
                e.printStackTrace();
            }

            prepareRecorder();
            if (!recording) {
                recording = true;
                recorder.start();
            }
        }
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        if (recording) {
            recorder.stop();
            recording = false;
        }
        recorder.release();
        if (usecamera) {
            previewRunning = false;
            // camera.lock();
            camera.release();
        }
        finish();
    }
}