Android指南针之加速度传感器地磁传感器-android学习之旅(67)

由于andorid不推荐用传统的方向传感器,推荐用加速度传感器和地磁传感器来构造得到方向传感器的数据,其实主要是z轴的旋转角度

具体代码示例

代码如下

public class MainActivity extends Activity {
    private ImageView compass;
    private SensorManager sensorManager;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        compass = (ImageView) findViewById(R.id.compass);
        sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        Sensor AccelerometerSensor = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        Sensor magneticSensor = sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
        sensorManager.registerListener(sensorEventListener,magneticSensor,SensorManager.SENSOR_DELAY_GAME);
        sensorManager.registerListener(sensorEventListener,AccelerometerSensor,SensorManager.SENSOR_DELAY_GAME);

    }
    private SensorEventListener sensorEventListener = new SensorEventListener() {
        float[] accelerometerValues = new float[3];
        float[] maneticValues = new float[3];
        private float lastDegree;
        @Override
        public void onSensorChanged(SensorEvent sensorEvent) {
            if (sensorEvent.sensor.getType() == Sensor.TYPE_ACCELEROMETER){
                accelerometerValues = sensorEvent.values.clone();
            }else if (sensorEvent.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD){
                maneticValues = sensorEvent.values.clone();
            }
            float[] R = new float[9];
            float[] values = new float[3];
            SensorManager.getRotationMatrix(R,null,accelerometerValues,maneticValues);
            SensorManager.getOrientation(R,values);
            float rotateDegree = -(float) Math.toDegrees(values[0]);
            if (Math.abs(rotateDegree - lastDegree) > 1){
                RotateAnimation animation = new RotateAnimation(lastDegree,rotateDegree, Animation.RELATIVE_TO_SELF,0.5f,Animation.RELATIVE_TO_SELF,0.5f);
                animation.setFillAfter(true);
                compass.startAnimation(animation);
                lastDegree = rotateDegree;
            }
        }

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

        }
    };
    @Override
    protected void onDestroy() {
        if (sensorManager != null){
            sensorManager.unregisterListener(sensorEventListener);
        }
        super.onDestroy();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

效果图