如何用android检测摇动事件？

<uses-permission android:name="android.permission.VIBRATE" />

import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.os.Vibrator;
import android.support.v7.app.AppCompatActivity;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements SensorEventListener {

    private SensorManager sensorManager;
    private boolean isShakeDetected = false;
    private long lastShakeTime;
    private static final int SHAKE_THRESHOLD = 800;
    private static final int SHAKE_TIMEOUT = 500;
    private Vibrator vibrator;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
        vibrator = (Vibrator) getSystemService(VIBRATOR_SERVICE);
    }

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

    @Override
    protected void onPause() {
        super.onPause();
        sensorManager.unregisterListener(this);
    }

    @Override
    public void onSensorChanged(SensorEvent event) {
        if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
            float x = event.values[0];
            float y = event.values[1];
            float z = event.values[2];

            long currentTime = System.currentTimeMillis();

            if ((currentTime - lastShakeTime) > SHAKE_TIMEOUT) {
                isShakeDetected = false;
            }

            if (!isShakeDetected && (Math.abs(x) > SHAKE_THRESHOLD || Math.abs(y) > SHAKE_THRESHOLD || Math.abs(z) > SHAKE_THRESHOLD)) {
                isShakeDetected = true;
                lastShakeTime = currentTime;
                Toast.makeText(this, "Device Shaken", Toast.LENGTH_SHORT).show();
                vibrator.vibrate(500); // 震动500毫秒
            }
        }
    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
        // 不需要实现
    }
}