如何使用线程在服务中拍照

Question

我想使用服务秘密拍照。这是代码：

** Takes a single photo on service start. */
public class PhotoTakingService extends Service {
    static String TAG = "Khan";
    private boolean isRunning  = false;

    @Override
    public void onCreate() {
        Log.d("shahjahan", "i am in photo taking service.");
        super.onCreate();

        Log.d(TAG, "the name of the for ground process is: " + getForgroundProcessName());

        takePhoto(this);

    }

    @SuppressWarnings("deprecation")
    private static void takePhoto(final Context context) {
        final SurfaceView preview = new SurfaceView(context);
        SurfaceHolder holder = preview.getHolder();
        // deprecated setting, but required on Android versions prior to 3.0
        holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

        holder.addCallback(new SurfaceHolder.Callback() {
            @Override
            //The preview must happen at or after this point or takePicture fails
            public void surfaceCreated(SurfaceHolder holder) {
                showMessage("Surface created");

                Camera camera = null;

                try {
                    camera = Camera.open();
                    showMessage("Opened camera");

                    try {
                        camera.setPreviewDisplay(holder);
                    } catch (IOException e) {
                        throw new RuntimeException(e);
                    }

                    camera.startPreview();
                    showMessage("Started preview");

                    camera.takePicture(null, null, new Camera.PictureCallback() {

                        @Override
                        public void onPictureTaken(byte[] data, Camera camera) {
                            showMessage("Took picture");
                            File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);
                            if (pictureFile == null){
                                Log.d(TAG, "Error creating media file, check storage permissions: ");
                                return;
                            }

                            try {
                                FileOutputStream fos = new FileOutputStream(pictureFile);
                                fos.write(data);
                                fos.close();
                            } catch (FileNotFoundException e) {
                                Log.d(TAG, "File not found: " + e.getMessage());
                            } catch (IOException e) {
                                Log.d(TAG, "Error accessing file: " + e.getMessage());
                            }

                            camera.release();
                        }
                    });
                } catch (Exception e) {
                    if (camera != null)
                        camera.release();
                    throw new RuntimeException(e);
                }
            }

            @Override public void surfaceDestroyed(SurfaceHolder holder) {}
            @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {}
        });

        WindowManager wm = (WindowManager)context
                .getSystemService(Context.WINDOW_SERVICE);
        WindowManager.LayoutParams params = new WindowManager.LayoutParams(
                1, 1, //Must be at least 1x1
                WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY,
                0,
                //Don't know if this is a safe default
                PixelFormat.UNKNOWN);

        //Don't set the preview visibility to GONE or INVISIBLE
        wm.addView(preview, params);
    }

    public static final int MEDIA_TYPE_IMAGE = 1;
    public static final int MEDIA_TYPE_VIDEO = 2;

    /** Create a file Uri for saving an image or video */
    private static Uri getOutputMediaFileUri(int type){
        return Uri.fromFile(getOutputMediaFile(type));
    }

    /** Create a File for saving an image or video */
    private static File getOutputMediaFile(int type){
        // To be safe, you should check that the SDCard is mounted
        // using Environment.getExternalStorageState() before doing this.

        File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_PICTURES), "MyCameraApp");
        // This location works best if you want the created images to be shared
        // between applications and persist after your app has been uninstalled.

        // Create the storage directory if it does not exist
        if (! mediaStorageDir.exists()){
            if (! mediaStorageDir.mkdirs()){
                Log.d("MyCameraApp", "failed to create directory");
                return null;
            }
        }

        // Create a media file name
        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        File mediaFile;
        if (type == MEDIA_TYPE_IMAGE){
            mediaFile = new File(mediaStorageDir.getPath() + File.separator +
                    "IMG_"+ timeStamp + ".jpg");
        } else if(type == MEDIA_TYPE_VIDEO) {
            mediaFile = new File(mediaStorageDir.getPath() + File.separator +
                    "VID_"+ timeStamp + ".mp4");
        } else {
            return null;
        }

        return mediaFile;
    }



    private static void showMessage(String message) {
        Log.i("Camera", message);
    }

    @Override public IBinder onBind(Intent intent) { return null; }


    public String getForgroundProcessName()
    {
        ActivityManager activityManager = (ActivityManager) this.getSystemService(Context.ACTIVITY_SERVICE);
        List<ActivityManager.RunningAppProcessInfo> appProcesses = activityManager.getRunningAppProcesses();
        for (ActivityManager.RunningAppProcessInfo appProcess : appProcesses) {
            if (appProcess.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) {
//                Log.i("Foreground App", appProcess.processName);
//                Toast.makeText(this, "the forground application is: " + appProcess.processName, Toast.LENGTH_LONG).show();
                return appProcess.processName;

            }
        }
        return "None";
    }

}

但是，我想在后台定期间隔后运行takePhoto(this)。我试过了handler，但是效果不好：

Handler uiHandler = new Handler(Looper.getMainLooper());
Runnable runnable = new Runnable() {

    @Override
    public void run() {
        // TODO Auto-generated method stub
        int i = 0;
        while(true)
        {
            Log.d(TAG,"I am in while.");
            i++;
            takePhoto(getApplicationContext());
            try {
                Thread.sleep(10000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            if ( i > 5 )
                break;
        }
    }
};

uiHandler.post(runnable);

使用上面的代码冻结我的应用程序。请指导我正确实施上述代码。