Android编程之方向传感器用法示例

/**
 * 传感器指针Demo
 *
 * @description：
 * @author ldm
 * @date 2016-4-25 下午5:29:18
 */
public class SensorHandActivity extends GraphicsActivity {
  // 传感器管理对象
  private SensorManager mSensorManager;
  // 传感器类
  private Sensor mSensor;
  // 自定义绘制指针View
  private MyCompassView mView;
  /**
   * 方向传感器检测到的感应值 values[0]: Azimuth(方位)，地磁北方向与y轴的角度，围绕z轴旋转(0到359)。0=North,
   * 90=East, 180=South, 270=West values[1]: Pitch(俯仰),围绕X轴旋转(-180 to 180),
   * 当Z轴向Y轴运动时是正值 values[2]: Roll(滚)，围绕Y轴旋转(-90 to 90)，当X轴向Z轴运动时是正值
   */
  private float[] mValues;
  // 传感监听
  private final SensorEventListener mSensorListener = new SensorEventListener() {
    public void onSensorChanged(SensorEvent event) {
      mValues = event.values;
      if (mView != null) {
        mView.invalidate();
      }
    }
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
    }
  };
  @SuppressWarnings("deprecation")
  @Override
  protected void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
    mSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION);
    mView = new MyCompassView(this);
    setContentView(mView);
  }
  @Override
  protected void onResume() {
    super.onResume();
    /**
     * 在onResume方法中注册传感器监听 事件
     * 第一个参数：监听Sensor事件，第二个参数是Sensor目标种类的值，第三个参数是延迟时间的精度密度。延迟时间的精密度参数 参数
     * 延迟时间 SensorManager.SENSOR_DELAY_FASTEST 0ms
     * SensorManager.SENSOR_DELAY_GAME 20ms SensorManager.SENSOR_DELAY_UI
     * 60ms SensorManager.SENSOR_DELAY_NORMAL 200ms
     */
    mSensorManager.registerListener(mSensorListener, mSensor,
        SensorManager.SENSOR_DELAY_GAME);
  }
  @Override
  protected void onStop() {
    // 在onStop方法中取消注册监听
    mSensorManager.unregisterListener(mSensorListener);
    super.onStop();
  }
  private class MyCompassView extends View {
    // 定义画笔Paint
    private Paint mPaint;
    // 定义绘制指针的路径Path
    private Path mPath;
    public MyCompassView(Context context) {
      super(context);
      initPaintAndPath();
    }
    private void initPaintAndPath() {
      // 初始化画笔
      mPaint = new Paint();
      mPaint.setAntiAlias(true);
      mPaint.setColor(Color.BLACK);
      mPaint.setStyle(Paint.Style.FILL);
      // 初始化绘制路径
      mPath = new Path();
      mPath.moveTo(0, -50);// 移动到指点点
      mPath.lineTo(-20, 60);// 用线条连接到指定点
      mPath.lineTo(0, 50);
      mPath.lineTo(20, 60);
      mPath.close();// 关闭路径
    }
    @Override
    protected void onDraw(Canvas canvas) {
      // 设置画面背景
      canvas.drawColor(Color.WHITE);
      int w = canvas.getWidth();
      int h = canvas.getHeight();
      int cx = w / 2;
      int cy = h / 2;
      canvas.translate(cx, cy);// 移动画面，把指针放到中央
      if (mValues != null) {
        canvas.rotate(-mValues[0]);
      }
      canvas.drawPath(mPath, mPaint);
    }
  }
}