android - 如何在android中移动摇动时获得时差？

Question

我的问题是如何通过在 android 中使用加速度计来获得摇动手机之间的持续时间。我的默认阈值为800，速度计算公式为：

speed = Math.abs(x+y+z - last_x - last_y - last_z)/ diffTime * 10000;

在这里，我想获得第一次摇动和下一次摇动之间的持续时间。如果持续时间超过 10 秒，则意味着必须生成警报。

我不知道如何计算传感器概念中的时间间隔。请帮我。

谢谢。

Answer 1

只需用于 System.currentTimeMillis()获取第一次摇动的时间并将其保存到某个变量中preTime，例如当用户再次摇动时，您可以像这样简单地减去时差 diffTime = System.currentTimeMillis() - preTime

现在如果值diffeTime/(1000 *10) > 10then 做你剩下的计算

Answer 2

要检查您的手机旋转，您可以使用加速度计传感器，

http://www.techrepublic.com/blog/app-builder/a-quick-tutorial-on-coding-androids-accelerometer/472

但是您需要使用此传感器检查完全旋转并增加旋转值

Answer 3

    private static final int FORCE_THRESHOLD = 800;
    private static final int TIME_THRESHOLD = 100;
    private static final int SHAKE_TIMEOUT = 500;
    private static final int SHAKE_DURATION = 1000;
    private static final int SHAKE_COUNT = 3;
    private float mLastX=-1.0f, mLastY=-1.0f, mLastZ=-1.0f;
    private long mLastTime;
    private Context mContext;
    private int mShakeCount = 0;
    private long mLastShake;
    private long mLastForce;



    public void onSensorChanged(SensorEvent event) {
                                if(event.sensor.getType() != Sensor.TYPE_ACCELEROMETER) return;

    Log.v("sensor","sensor change is verifying");
    long now = System.currentTimeMillis();

    if ((now - mLastForce) > SHAKE_TIMEOUT) {
        mShakeCount = 0;
    }

    if ((now - mLastTime) > TIME_THRESHOLD) {
      long diff = now - mLastTime;
      float speed = Math.abs(event.values[SensorManager.DATA_X] + event.values[SensorManager.DATA_Y] + event.values[SensorManager.DATA_Z] - mLastX - mLastY - mLastZ) / diff * 10000;
      if (speed > FORCE_THRESHOLD) {
        if ((++mShakeCount >= SHAKE_COUNT) && (now - mLastShake > SHAKE_DURATION)) 
        {
           mLastShake = now;
           mShakeCount = 0;
            //call the reaction you want to have happen
            onShake();
         }
         mLastForce = now;
       }
         mLastTime = now;
         mLastX = event.values[SensorManager.DATA_X];
         mLastY = event.values[SensorManager.DATA_Y];
         mLastZ = event.values[SensorManager.DATA_Z];
      }
  }