Followed tutorial on creating a shake listener, having trouble using it

Question

I'm simply trying to learn android using baby-steps. I've followed a tutorial on how to implement a "shake listener" from this tutorial

This is it:

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

public class ShakeListener 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 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);
            }
        }
    }
}

I read jokes from a folder and I'd like to display a new one every time I shake the phone. I have no idea how to call the shake listener.

private SensorManager mSensorManager;
private Sensor mAccelerometer;
private ShakeListener mShakeListener;

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    Intent intent = getIntent();
    String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);

    TextView textView = new TextView(this);
    textView.setTextSize(16);
    String[] test = processData(readText(message));
    textView.setText(test[0]); // later will use random

    //________________________________________________
    // THIS IS THE PART I HAVE NO IDEA HOW TO IMPLEMENT.
    while (true) {
        if (shake) 
           textView.setText(test[RandomNumber]);
    }
    //________________________________________________

    setContentView(textView);
}

I think this is what I should use, but frankly I don't understand what's going on:

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

    @Override
    public void onShake(int count) {
        /*
         * The following method, "handleShakeEvent(count):" is a stub //
         * method you would use to setup whatever you want done once the
         * device has been shook.
         */
        handleShakeEvent(count);
    }
});

Answer 1

You don't call Listeners. They call you.

Move:

while (true) {
    if (shake) 
       textView.setText(test[RandomNumber]);  // this line
}

to:

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

Should achieve what you're aiming for.