How to refresh app upon shaking the device?

Question

I need to add a shake feature that will refresh my Android application.

All I find of documentation involves implementing the SensorListener, but Eclipse tells me it's deprecated and suggest SensorEventListener.

Anybody that has a nice guide to how I go about creating this shake controller?

Answer 1

Here is an example code. Put this into your activity class:

  /* put this into your activity class */
  private SensorManager mSensorManager;
  private float mAccel; // acceleration apart from gravity
  private float mAccelCurrent; // current acceleration including gravity
  private float mAccelLast; // last acceleration including gravity

  private final SensorEventListener mSensorListener = new SensorEventListener() {

    public void onSensorChanged(SensorEvent se) {
      float x = se.values[0];
      float y = se.values[1];
      float z = se.values[2];
      mAccelLast = mAccelCurrent;
      mAccelCurrent = (float) Math.sqrt((double) (x*x + y*y + z*z));
      float delta = mAccelCurrent - mAccelLast;
      mAccel = mAccel * 0.9f + delta; // perform low-cut filter
    }

    public void onAccuracyChanged(Sensor sensor, int accuracy) {
    }
  };

  @Override
  protected void onResume() {
    super.onResume();
    mSensorManager.registerListener(mSensorListener, mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_NORMAL);
  }

  @Override
  protected void onPause() {
    mSensorManager.unregisterListener(mSensorListener);
    super.onPause();
  }

And add this to your onCreate method:

    /* do this in onCreate */
    mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
    mSensorManager.registerListener(mSensorListener, mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_NORMAL);
    mAccel = 0.00f;
    mAccelCurrent = SensorManager.GRAVITY_EARTH;
    mAccelLast = SensorManager.GRAVITY_EARTH;

You can then ask "mAccel" wherever you want in your application for the current acceleration, independent from the axis and cleaned from static acceleration such as gravity. It will be approx. 0 if there is no movement, and, lets say >2 if the device is shaked.

Based on the comments - to test this:

if (mAccel > 12) {
    Toast toast = Toast.makeText(getApplicationContext(), "Device has shaken.", Toast.LENGTH_LONG);
    toast.show();
}

Notes:

The accelometer should be deactivated onPause and activated onResume to save resources (CPU, Battery). The code assumes we are on planet Earth ;-) and initializes the acceleration to earth gravity. Otherwise you would get a strong "shake" when the application starts and "hits" the ground from free-fall. However, the code gets used to the gravitation due to the low-cut filter and would work also on other planets or in free space, once it is initialized. (you never know how long your application will be in use...;-)

Answer 2

package anywheresoftware.b4a.student;

import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.util.FloatMath;

public class ShakeEventListener implements SensorEventListener {

    /*
     * The gForce that is necessary to register as shake.
     * Must be greater than 1G (one earth gravity unit).
     * You can install "G-Force", by Blake La Pierre
     * from the Google Play Store and run it to see how
     *  many G's it takes to register a shake
     */
    private static final float SHAKE_THRESHOLD_GRAVITY = 2.7F;
    private static int SHAKE_SLOP_TIME_MS = 500;
    private static final int SHAKE_COUNT_RESET_TIME_MS = 1000;

    private OnShakeListener mListener;
    private long mShakeTimestamp;
    private int mShakeCount;

    public void setOnShakeListener(OnShakeListener listener) {
        this.mListener = listener;
    }

    public interface OnShakeListener {
        public void onShake(int count);
    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
        // ignore
    }

    @Override
    public void onSensorChanged(SensorEvent event) {

        if (mListener != null) {
            float x = event.values[0];
            float y = event.values[1];
            float z = event.values[2];

            float gX = x / SensorManager.GRAVITY_EARTH;
            float gY = y / SensorManager.GRAVITY_EARTH;
            float gZ = z / SensorManager.GRAVITY_EARTH;

            // gForce will be close to 1 when there is no movement.
            float gForce = FloatMath.sqrt(gX * gX + gY * gY + gZ * gZ);

            if (gForce > SHAKE_THRESHOLD_GRAVITY) {
                final long now = System.currentTimeMillis();
                // ignore shake events too close to each other (500ms)
                if (mShakeTimestamp + getSHAKE_SLOP_TIME_MS() > now) {
                    return;
                }

                // reset the shake count after 3 seconds of no shakes
                if (mShakeTimestamp + SHAKE_COUNT_RESET_TIME_MS < now) {
                    mShakeCount = 0;
                }

                mShakeTimestamp = now;
                mShakeCount++;

                mListener.onShake(mShakeCount);
            }
        }
    }

    private long getSHAKE_SLOP_TIME_MS() {
        // TODO Auto-generated method stub
        return SHAKE_SLOP_TIME_MS;
    }

    public void setSHAKE_SLOP_TIME_MS(int sHAKE_SLOP_TIME_MS) {
        SHAKE_SLOP_TIME_MS = sHAKE_SLOP_TIME_MS;
    }   

}

Answer 3

Here is another code for this:

import java.util.List;
import java.util.Timer;
import java.util.TimerTask;

import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Handler;

   public class AccelerometerListener implements SensorEventListener {

        private SensorManager sensorManager;
        private List<Sensor> sensors;
        private Sensor sensor;
        private long lastUpdate = -1;
        private long currentTime = -1;
        private Main parent;
        private Timer timer;
        private int shakes;
        private static final Handler mHandler = new Handler();

        private float last_x, last_y, last_z;
        private float current_x, current_y, current_z, currenForce;
        private static final int FORCE_THRESHOLD = 500;
        private final int DATA_X = SensorManager.DATA_X;
        private final int DATA_Y = SensorManager.DATA_Y;
        private final int DATA_Z = SensorManager.DATA_Z;

        public AccelerometerListener(Main parent) {
            SensorManager sensorService = (SensorManager) parent
                    .getSystemService(Context.SENSOR_SERVICE);

            this.sensorManager = sensorService;
            if (sensorService == null)
                return;

            this.sensors = sensorManager.getSensorList(Sensor.TYPE_ACCELEROMETER);
            if (sensors.size() > 0) {
                sensor = sensors.get(0);
            }

            this.parent = parent;
        }

        public void start() {
            if (sensor == null)
                return;

            sensorManager.registerListener(this, sensor,
                    SensorManager.SENSOR_DELAY_GAME);
        }

        public void stop() {
            if (sensorManager == null)
                return;

            sensorManager.unregisterListener(this);
        }

        public void onAccuracyChanged(Sensor s, int valu) {

        }

        public void onSensorChanged(SensorEvent event) {

            if (event.sensor.getType() != Sensor.TYPE_ACCELEROMETER)
                return;

            currentTime = System.currentTimeMillis();

            if ((currentTime - lastUpdate) > 50) {
                long diffTime = (currentTime - lastUpdate);
                lastUpdate = currentTime;

                current_x = event.values[DATA_X];
                current_y = event.values[DATA_Y];
                current_z = event.values[DATA_Z];

                currenForce = Math.abs(current_x + current_y + current_z - last_x
                        - last_y - last_z)
                        / diffTime * 10000;

                if (currenForce > FORCE_THRESHOLD) {
                    shakeDetected();
                }
                last_x = current_x;
                last_y = current_y;
                last_z = current_z;

            }
        }

        private void shakeDetected() {
            shakes++;

            if (shakes == 1) {
                if (timer != null) {
                    timer.cancel();
                }

                timer = new Timer();
                timer.schedule(new TimerTask() {

                    @Override
                    public void run() {
                        if (shakes > 3) {
                            mHandler.post(new Runnable() {

                                public void run() {
                                    // shake
                                }
                            });
                        }

                        shakes = 0;
                    }
                }, 500);
            }
        }
    }

Answer 4

// Need to implement SensorListener
public class ShakeActivity extends Activity implements SensorListener {
// For shake motion detection.
private SensorManager sensorMgr;
private long lastUpdate = -1;
private float x, y, z;
private float last_x, last_y, last_z;
private static final int SHAKE_THRESHOLD = 800;

protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// start motion detection
sensorMgr = (SensorManager) getSystemService(SENSOR_SERVICE);
boolean accelSupported = sensorMgr.registerListener(this,
    SensorManager.SENSOR_ACCELEROMETER,
    SensorManager.SENSOR_DELAY_GAME);

if (!accelSupported) {
    // on accelerometer on this device
    sensorMgr.unregisterListener(this,
            SensorManager.SENSOR_ACCELEROMETER);
}
}

protected void onPause() {
if (sensorMgr != null) {
    sensorMgr.unregisterListener(this,
            SensorManager.SENSOR_ACCELEROMETER);
    sensorMgr = null;
    }
super.onPause();
}

public void onAccuracyChanged(int arg0, int arg1) {
// TODO Auto-generated method stub
}

public void onSensorChanged(int sensor, float[] values) {
if (sensor == SensorManager.SENSOR_ACCELEROMETER) {
    long curTime = System.currentTimeMillis();
    // only allow one update every 100ms.
    if ((curTime - lastUpdate)> 100) {
    long diffTime = (curTime - lastUpdate);
    lastUpdate = curTime;

    x = values[SensorManager.DATA_X];
    y = values[SensorManager.DATA_Y];
    z = values[SensorManager.DATA_Z];

    float speed = Math.abs(x+y+z - last_x - last_y - last_z)
                          / diffTime * 10000;
    if (speed > SHAKE_THRESHOLD) {
        // yes, this is a shake action! Do something about it!
    }
    last_x = x;
    last_y = y;
    last_z = z;
    }
}
}
}

Answer 5

Working with me v.good Reference

public class ShakeEventListener implements SensorEventListener {
public final static int SHAKE_LIMIT = 15;
public final static int LITTLE_SHAKE_LIMIT = 5;

private SensorManager mSensorManager;
private float mAccel = 0.00f;
private float mAccelCurrent = SensorManager.GRAVITY_EARTH;
private float mAccelLast = SensorManager.GRAVITY_EARTH;

private ShakeListener listener;

public interface ShakeListener {
    public void onShake();
    public void onLittleShake();
}

public ShakeEventListener(ShakeListener l) {
    Activity a = (Activity) l;
    mSensorManager = (SensorManager) a.getSystemService(Context.SENSOR_SERVICE);
    listener = l;
    registerListener();
}

public ShakeEventListener(Activity a, ShakeListener l) {
    mSensorManager = (SensorManager) a.getSystemService(Context.SENSOR_SERVICE);
    listener = l;
    registerListener();
}

public void registerListener() {
    mSensorManager.registerListener(this, mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_NORMAL);
}

public void unregisterListener() {
    mSensorManager.unregisterListener(this);
}

public void onSensorChanged(SensorEvent se) {
    float x = se.values[0];
    float y = se.values[1];
    float z = se.values[2];
    mAccelLast = mAccelCurrent;
    mAccelCurrent = (float) FloatMath.sqrt(x*x + y*y + z*z);
    float delta = mAccelCurrent - mAccelLast;
    mAccel = mAccel * 0.9f + delta;
    if(mAccel > SHAKE_LIMIT)
        listener.onShake();
    else if(mAccel > LITTLE_SHAKE_LIMIT)
        listener.onLittleShake();
}

public void onAccuracyChanged(Sensor sensor, int accuracy) {}
}

Answer 6

I really liked Peterdk's answer. I took it upon myself to make a coulpe of tweaks to his code .

file: ShakeDetector.java

import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.util.FloatMath;

public class ShakeDetector implements SensorEventListener {

    // The gForce that is necessary to register as shake. Must be greater than 1G (one earth gravity unit)
    private static final float SHAKE_THRESHOLD_GRAVITY = 2.7F;
    private static final int SHAKE_SLOP_TIME_MS = 500;
    private static final int SHAKE_COUNT_RESET_TIME_MS = 3000;

    private OnShakeListener mListener;
    private long mShakeTimestamp;
    private int mShakeCount;

    public void setOnShakeListener(OnShakeListener listener) {
        this.mListener = listener;
    }

    public interface OnShakeListener {
        public void onShake(int count);
    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
        // ignore
    }

    @Override
    public void onSensorChanged(SensorEvent event) {

        if (mListener != null) {
            float x = event.values[0];
            float y = event.values[1];
            float z = event.values[2];

            float gX = x / SensorManager.GRAVITY_EARTH;
            float gY = y / SensorManager.GRAVITY_EARTH;
            float gZ = z / SensorManager.GRAVITY_EARTH;

            // gForce will be close to 1 when there is no movement.
            float gForce = FloatMath.sqrt(gX * gX + gY * gY + gZ * gZ);

            if (gForce > SHAKE_THRESHOLD_GRAVITY) {
                final long now = System.currentTimeMillis();
                // ignore shake events too close to each other (500ms)
                if (mShakeTimestamp + SHAKE_SLOP_TIME_MS > now ) {
                    return;
                }

                // reset the shake count after 3 seconds of no shakes
                if (mShakeTimestamp + SHAKE_COUNT_RESET_TIME_MS < now ) {
                    mShakeCount = 0;
                }

                mShakeTimestamp = now;
                mShakeCount++;

                mListener.onShake(mShakeCount);
            }
        }
    }
}

Also, don't forget that you need to register an instance of the ShakeDetector with the SensorManager.

// ShakeDetector initialization
mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
mShakeDetector = new ShakeDetector();
mShakeDetector.setOnShakeListener(new OnShakeListener() {

    @Override
    public void onShake(int count) {
            handleShakeEvent(count); 
        }
    });

mSensorManager.registerListener(mShakeDetector, mAccelerometer, SensorManager.SENSOR_DELAY_UI);