Shake Detector in Android

In Android, the most commonly used sensors are the accelerometer, it is used to measure acceleration. Here it is explained how to detect a shake motion.

Step 1. Create Class ShakeDetector that will extend SensorEventListener:-

Step 1(a) :-  Declare the required variable :-

1. /*gForce Must be greater than 1G (one earth gravity unit).*/

3. private static final float THRESHOLD_GRAVITY = 3.2F;

4. private static final int SLOP_TIME_MS = 1000; /*This decide after how much interval shake will detect */

5. private static final int COUNT_RESET_TIME_MS = 3000;

6. private Double mAccelCurrent, gForce = 0.00, mAccelLast = 0.00, mAccel = 0.00;

7. private OnShakeListener mListener;

9. private long mShakeTimestamp;

10. private int mShakeCount;

Step 1(b) :-  Override its function :-

In your onSensorChange() method, you determine whether it’s a shake or not.

Here we calculate the magnitude of the acceleration correctly and correctly applies a timeout between shake events.

1. @Override

2.   public void onAccuracyChanged(Sensor sensor, int accuracy) {

3.       MyUtilities.showLog("On sensor" + sensor);

4.       MyUtilities.showLog("On accuracy" + accuracy);

5.   }

8.   @Override

9.   public void onSensorChanged(SensorEvent event) {

10.       DecimalFormat twoDForm = new DecimalFormat("#.#");

11.       if (mListener != null) {

12.           float x = event.values[0];

13.           float y = event.values[1];

14.           float z = event.values[2];

15.           float gravityX = x / SensorManager.GRAVITY_EARTH;

16.           float gravityY = y / SensorManager.GRAVITY_EARTH;

17.           float gravityZ = z / SensorManager.GRAVITY_EARTH;

20.           // gForce==1, when there is no movement.

21.           mAccelCurrent = gForce;

22.           gForce = (Double) Math.sqrt(gX * gX + gY * gY + gZ * gZ);

23.           Double delta = mAccelCurrent - mAccelLast;

24.           mAccel = mAccel * 0.9f + delta;

25.           mAccel = Double.valueOf(twoDForm.format(mAccel));

26.           if (gForce >THRESHOLD_GRAVITY) {

27.               final long now = System.currentTimeMillis();

28.               // ignore shake events too close to each other (1000ms)

29.               if (mShakeTimestamp + SLOP_TIME_MS > now) {

30.                   return;

31.               }

32.               // reset the shake count after 3 seconds of no shakes

33.               if (mShakeTimestamp + COUNT_RESET_TIME_MS < now) {

34.                   mShakeCount = 0;

35.               }

36.               mShakeTimestamp = now;

37.               mShakeCount++;

38.               mListener.onShake(mShakeCount);

41.           }

44.       }

45.   }

Read more about the Shake Detector in Android visit Findnerd.