如何检测android设备平行于地面的旋转？

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

public class MainActivity extends AppCompatActivity implements SensorEventListener {

    private SensorManager sensorManager;
    private Sensor accelerometer;
    private Sensor gyroscope;

    private static final float THRESHOLD = 0.1f; // 阈值，用于判断设备是否旋转

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

        sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
        accelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        gyroscope = sensorManager.getDefaultSensor(Sensor.TYPE_GYROSCOPE);
    }

    @Override
    protected void onResume() {
        super.onResume();
        sensorManager.registerListener(this, accelerometer, SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this, gyroscope, 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];

            // 判断设备是否平行于地面旋转
            if (Math.abs(x) < THRESHOLD && Math.abs(y) < THRESHOLD && z > 9.8 - THRESHOLD && z < 9.8 + THRESHOLD) {
                Toast.makeText(this, "设备平行于地面旋转", Toast.LENGTH_SHORT).show();
            }
        } else if (event.sensor.getType() == Sensor.TYPE_GYROSCOPE) {
            float x = event.values[0];
            float y = event.values[1];
            float z = event.values[2];

            // 判断设备是否平行于地面旋转
            if (Math.abs(x) < THRESHOLD && Math.abs(y) < THRESHOLD && Math.abs(z) < THRESHOLD) {
                Toast.makeText(this, "设备平行于地面旋转", Toast.LENGTH_SHORT).show();
            }
        }
    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
        // 精度变化时的处理
    }
}