Android 中的相机方向问题

Android中的相机方向问题

java
public class CameraActivity extends AppCompatActivity implements SensorEventListener {
    private SensorManager mSensorManager;
    private Sensor mAccelerometer;
    private Sensor mMagnetometer;
    private float[] mGravity;
    private float[] mGeomagnetic;
    private int mRotation;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_camera);
        mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        mMagnetometer = mSensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
    }
    @Override
    protected void onResume() {
        super.onResume();
        mSensorManager.registerListener(this, mAccelerometer, SensorManager.SENSOR_DELAY_NORMAL);
        mSensorManager.registerListener(this, mMagnetometer, SensorManager.SENSOR_DELAY_NORMAL);
    }
    @Override
    protected void onPause() {
        super.onPause();
        mSensorManager.unregisterListener(this);
    }
    @Override
    public void onSensorChanged(SensorEvent event) {
        if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER)
            mGravity = event.values;
        if (event.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD)
            mGeomagnetic = event.values;
        if (mGravity != null && mGeomagnetic != null) {
            float[] rotationMatrix = new float[9];
            boolean success = SensorManager.getRotationMatrix(rotationMatrix, null, mGravity, mGeomagnetic);
            if (success) {
                float[] orientation = new float[3];
                SensorManager.getOrientation(rotationMatrix, orientation);
                float azimuth = orientation[0]; // 方位角
                float pitch = orientation[1]; // 倾斜角
                float roll = orientation[2]; // 旋转角
                mRotation = (int) Math.toDegrees(roll);
                // 设置相机的方向
                setCameraRotation(mRotation);
            }
        }
    }
    private void setCameraRotation(int rotation) {
        Camera.CameraInfo info = new Camera.CameraInfo();
        Camera.getCameraInfo(Camera.CameraInfo.CAMERA_FACING_BACK, info);
        int result = (info.orientation - rotation + 360) % 360;
        Camera.Parameters params = mCamera.getParameters();
        params.setRotation(result);
        mCamera.setParameters(params);
    }
    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
        // 空实现
    }
}