您可以假设在2 已移动事件之间的时间内触摸静止。

You can assume a touch in the time between 2 Moved events as stationary.

（ UITouchPhaseStationary 因多点触控而存在。如果一根手指移动而另一根没有，则移动事件仍然被触发，但静止触摸将处于 UITouchPhaseStationary 阶段。）

(UITouchPhaseStationary exists because of multitouch. If one finger moves while the other doesn't, a Moved event is still triggered, but the stationary touch will be in the phase UITouchPhaseStationary.)