I am working on an Android project which takes the heart rate. The application runs fine but it continuously does processing and gives different readings. I want the application to stop processing the image after a set time. I have used the postDelayed method, but it didn't work or maybe I didn't use it right. Maybe someone can help. Below is the class that does the image processing. How do I stop it from processing after about 20 seconds?
/**
   * This class extends Activity to handle a picture preview, process the preview
    * for a red values and determine a heart beat.
    */
public class HeartRateMonitor extends Activity {
private static final String TAG = "HeartRateMonitor";
private static final AtomicBoolean processing = new AtomicBoolean(false);
private static SurfaceView preview = null;
private static SurfaceHolder previewHolder = null;
private static Camera camera = null;
private static View image = null;
private static TextView text = null;
private static WakeLock wakeLock = null;
private static int averageIndex = 0;
private static final int averageArraySize = 4;
private static final int[] averageArray = new int[averageArraySize];
public static enum TYPE {
    GREEN, RED
};
private static TYPE currentType = TYPE.GREEN;
public static TYPE getCurrent() {
    return currentType;
}
private static int beatsIndex = 0;
private static final int beatsArraySize = 3;
private static final int[] beatsArray = new int[beatsArraySize];
private static double beats = 0;
private static long startTime = 0;
/**
 * {@inheritDoc}
 */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_heart_beat_rate);
    preview = (SurfaceView) findViewById(R.id.preview);
    previewHolder = preview.getHolder();
    previewHolder.addCallback(surfaceCallback);
    previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    image = findViewById(R.id.image);
    text = (TextView) findViewById(R.id.text);
     PowerManager pm = (PowerManager)  getSystemService(Context.POWER_SERVICE);
    wakeLock = pm.newWakeLock(PowerManager.FULL_WAKE_LOCK, "DoNotDimScreen");
}
/**
 * {@inheritDoc}
 */
@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
}
/**
 * {@inheritDoc}
 */
@Override
public void onResume() {
    super.onResume();
    wakeLock.acquire();
    camera = Camera.open();
    startTime = System.currentTimeMillis();
}
/**
 * {@inheritDoc}
 */
@Override
public void onPause() {
    super.onPause();
    wakeLock.release();
    camera.setPreviewCallback(null);
    camera.stopPreview();
    camera.release();
    camera = null;
}
private PreviewCallback previewCallback = new PreviewCallback() {
    /**
     * {@inheritDoc}
     */
    @Override
    public void onPreviewFrame(byte[] data, Camera cam) {
        if (data == null) throw new NullPointerException();
        Camera.Size size = cam.getParameters().getPreviewSize();
        if (size == null) throw new NullPointerException();
        if (!processing.compareAndSet(false, true)) return;
        int width = size.width;
        int height = size.height;
        int imgAvg = ImageProcessing.decodeYUV420SPtoRedAvg(data.clone(), height, width);
        // Log.i(TAG, "imgAvg="+imgAvg);
        if (imgAvg == 0 || imgAvg == 255) {
            processing.set(false);
            return;
        }
        int averageArrayAvg = 0;
        int averageArrayCnt = 0;
        for (int i = 0; i < averageArray.length; i++) {
            if (averageArray[i] > 0) {
                averageArrayAvg += averageArray[i];
                averageArrayCnt++;
            }
        }
        int rollingAverage = (averageArrayCnt > 0) ? (averageArrayAvg / averageArrayCnt) : 0;
        TYPE newType = currentType;
        if (imgAvg < rollingAverage) {
            newType = TYPE.RED;
            if (newType != currentType) {
                beats++;
                // Log.d(TAG, "BEAT!! beats="+beats);
            }
        } else if (imgAvg > rollingAverage) {
            newType = TYPE.GREEN;
        }
        if (averageIndex == averageArraySize) averageIndex = 0;
        averageArray[averageIndex] = imgAvg;
        averageIndex++;
        // Transitioned from one state to another to the same
        if (newType != currentType) {
            currentType = newType;
            image.postInvalidate();
        }
        long endTime = System.currentTimeMillis();
        double totalTimeInSecs = (endTime - startTime) / 1000d;
        if (totalTimeInSecs >= 10) {
            double bps = (beats / totalTimeInSecs);
            int dpm = (int) (bps * 60d);
            if (dpm < 20 || dpm > 120) {
                startTime = System.currentTimeMillis();
                beats = 0;
                processing.set(false);
                return;
            }
            // Log.d(TAG,
            if (beatsIndex == beatsArraySize) beatsIndex = 0;
            beatsArray[beatsIndex] = dpm;
            beatsIndex++;
            int beatsArrayAvg = 0;
            int beatsArrayCnt = 0;
            for (int i = 0; i < beatsArray.length; i++) {
                if (beatsArray[i] > 0) {
                    beatsArrayAvg += beatsArray[i];
                    beatsArrayCnt++;
                }
            }
            startTime = System.currentTimeMillis();
            beats = 0;
            final int beatsAvg = (beatsArrayAvg / beatsArrayCnt);
            // final ArrayList HeartRateResultPojoObjArrayList = new ArrayList();
            //maybe here
                    final AlertDialog alertDialog = new AlertDialog.Builder(HeartRateMonitor.this).create();
                    alertDialog.setTitle("Your Heart Rate is:");
                    alertDialog.setMessage(String.valueOf(beatsAvg) + " bpm");
                    alertDialog.setIcon(R.drawable.green_icon);
                    alertDialog.setButton(BUTTON_NEUTRAL, "Save",
                            new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog, int which) {
                                    Intent newActivityIntent = new  Intent(HeartRateMonitor.this, History.class);
                                    startActivity(newActivityIntent);
                                }
                            });
                    alertDialog.setButton(BUTTON_POSITIVE, "Share Result with a Doctor", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            try {
                                Intent sendIntent = new Intent(Intent.ACTION_VIEW);
                                sendIntent.putExtra("sms_body", "My Heart Rate is  " + String.valueOf(beatsAvg) + "bpm. " + " Any Advice for me?");
                                sendIntent.setType("vnd.android-dir/mms-sms");
                                startActivity(sendIntent);
                            } catch (Exception e) {
                                Toast.makeText(getApplicationContext(),
                                        "SMS failed, please try again later!",
                                        Toast.LENGTH_LONG).show();
                                e.printStackTrace();
                            }
                        }
                    });
            new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    alertDialog.show();
                }
            }, 25000);
                }
        processing.set(false);
    }
};
 private SurfaceHolder.Callback surfaceCallback = new SurfaceHolder.Callback() {
    /**
     * {@inheritDoc}
     */
    @SuppressLint("LongLogTag")
    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        try {
            camera.setPreviewDisplay(previewHolder);
            camera.setPreviewCallback(previewCallback);
        } catch (Throwable t) {
            Log.e("PreviewDemo-surfaceCallback", "Exception in setPreviewDisplay()", t);
        }
    }
    /**
     * {@inheritDoc}
     */
    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        Camera.Parameters parameters = camera.getParameters();
        parameters.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
        Camera.Size size = getSmallestPreviewSize(width, height, parameters);
        if (size != null) {
            parameters.setPreviewSize(size.width, size.height);
            Log.d(TAG, "Using width=" + size.width + " height=" + size.height);
        }
        camera.setParameters(parameters);
        camera.startPreview();
    }
    /**
     * {@inheritDoc}
     */
    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        // Ignore
    }
};
 private Camera.Size getSmallestPreviewSize(int width, int height, Camera.Parameters parameters) {
    Camera.Size result = null;
    for (Camera.Size size : parameters.getSupportedPreviewSizes()) {
        if (size.width <= width && size.height <= height) {
            if (result == null) {
                result = size;
            } else {
                int resultArea = result.width * result.height;
                int newArea = size.width * size.height;
                if (newArea < resultArea) result = size;
            }
        }
    }
    return result;
    }
}
What method should I use? And where in the above code should I place it to achieve my goal?
 
     
    