How to create a ShakeListener for Android
Here is the implementation of my ShakeListener that I used for ShotShakr. I was very lucky to find this piece of code that does all the heavy lifting for me.
public class ShakeListener implements SensorListener
{
private static final int FORCE_THRESHOLD = 350;
private static final int TIME_THRESHOLD = 100;
private static final int SHAKE_TIMEOUT = 500;
private static final int SHAKE_DURATION = 1000;
private static final int SHAKE_COUNT = 3;
private SensorManager mSensorMgr;
private float mLastX=-1.0f, mLastY=-1.0f, mLastZ=-1.0f;
private long mLastTime;
private OnShakeListener mShakeListener;
private Context mContext;
private int mShakeCount = 0;
private long mLastShake;
private long mLastForce;
public interface OnShakeListener
{
public void onShake();
}
public ShakeListener(Context context)
{
mContext = context;
resume();
}
public void setOnShakeListener(OnShakeListener listener)
{
mShakeListener = listener;
}
public void resume() {
mSensorMgr = (SensorManager)mContext.getSystemService(Context.SENSOR_SERVICE);
if (mSensorMgr == null) {
throw new UnsupportedOperationException("Sensors not supported");
}
boolean supported = mSensorMgr.registerListener(this, SensorManager.SENSOR_ACCELEROMETER, SensorManager.SENSOR_DELAY_GAME);
if (!supported) {
mSensorMgr.unregisterListener(this, SensorManager.SENSOR_ACCELEROMETER);
throw new UnsupportedOperationException("Accelerometer not supported");
}
}
public void pause() {
if (mSensorMgr != null) {
mSensorMgr.unregisterListener(this, SensorManager.SENSOR_ACCELEROMETER);
mSensorMgr = null;
}
}
public void onAccuracyChanged(int sensor, int accuracy) { }
public void onSensorChanged(int sensor, float[] values)
{
if (sensor != SensorManager.SENSOR_ACCELEROMETER) return;
long now = System.currentTimeMillis();
if ((now - mLastForce) > SHAKE_TIMEOUT) {
mShakeCount = 0;
}
if ((now - mLastTime) > TIME_THRESHOLD) {
long diff = now - mLastTime;
float speed = Math.abs(values[SensorManager.DATA_X] + values[SensorManager.DATA_Y] + values[SensorManager.DATA_Z] - mLastX - mLastY - mLastZ) / diff * 10000;
if (speed > FORCE_THRESHOLD) {
if ((++mShakeCount >= SHAKE_COUNT) && (now - mLastShake > SHAKE_DURATION)) {
mLastShake = now;
mShakeCount = 0;
if (mShakeListener != null) {
mShakeListener.onShake();
}
}
mLastForce = now;
}
mLastTime = now;
mLastX = values[SensorManager.DATA_X];
mLastY = values[SensorManager.DATA_Y];
mLastZ = values[SensorManager.DATA_Z];
}
}
In my implementation of this code i bumped up the FORCE_THRESHOLD to 1050. This seemed like a good threshold for as it was not to sensitive where you would loose any shot currently on display if you accidentally bumped your arm.
Implementing your ShakerListener on your activity
ShakeListener mShake = new ShakeListener(this);
mShake.setOnShakeListener(new ShakeListener.OnShakeListener() {
public void onShake() {
// DO WORK
}
});
It is really that simple. I have had a lot of luck with this implementation and hope you will to.
credit to Matthew Wiggins for the code.
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