Android Orientation Sensor

package zhangphil.sensor;

import android.content.Context;
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.util.Log;

public class MainActivity extends AppCompatActivity {
    private String TAG = "ZHANG PHIL";
    private SensorManager mSensorManager;

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

        startSensor();
    }

    /**
     * 启动传感器。
     */
    private void startSensor() {
        mSensorManager = (SensorManager) this.getSystemService(Context.SENSOR_SERVICE);

        Sensor mSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION);
        if (mSensorManager == null || mSensor == null) {
            throw new UnsupportedOperationException("设备不支持");
        }

        boolean isRegister = mSensorManager.registerListener(mSensorEventListener, mSensor, SensorManager.SENSOR_DELAY_NORMAL);
        if (!isRegister) {
            throw new UnsupportedOperationException();
        }
    }

    private SensorEventListener mSensorEventListener = new SensorEventListener() {

        private float x = 0, x_old = 0, y = 0, y_old = 0, z = 0, z_old = 0;

        @Override
        public void onSensorChanged(SensorEvent sensorEvent) {
            z = sensorEvent.values[0];
            x = sensorEvent.values[1];
            y = sensorEvent.values[2];

            Log.d(TAG, x + " , " + y + " , " + z);

            if (Math.abs(z - z_old) > 45) {
                Log.d(TAG, "横竖屏切换");
            }

            x_old = x;
            y_old = y;
            z_old = z;
        }

        @Override
        public void onAccuracyChanged(Sensor sensor, int i) {

        }
    };

    @Override
    protected void onDestroy() {
        super.onDestroy();
        mSensorManager.unregisterListener(mSensorEventListener);
    }
}