Android指南针之加速度传感器地磁传感器

由于andorid不建议使用传统的方向传感器，建议使用加速度传感器和地磁传感器来构建方向传感器的数据，实际上主要是z轴的旋转角度。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);

            //获取方向角度，可根据需要应用             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);     } }