我试图实现触摸监听器片，以触发取决于它是否touchmoved向上或向下的一些动作。

i'm trying to implement a touch listener for tablets to trigger some actions depending whether it touchmoved upwards or downwards.

我尝试了本地监听器：

($document).bind('touchmove', function (e)
{
    alert("it worked but i don't know the direction");
});

但我不知道如何确定的方向。

But i don't know how to determine the direction.

这可能吗？

或者我需要使用touchstart / touchend，如果我需要这个我能确定方向的触摸运动停止前？

Or do i need to use touchstart/touchend, if I need this can I determine the direction before the touch movement stops?

如果我只能做到这一点与外部库，什么是最好的？

If I can only do this with an external library, what's the best one?

感谢。

推荐答案

您需要保存触摸的最后一个位置，然后把它比作当前之一。 粗例如：

You need to save the last position of the touch, then compare it to the current one. Rough example:

var lastY;
$(document).bind('touchmove', function (e){
     var currentY = e.originalEvent.touches[0].clientY;
     if(currentY > lastY){
         // moved down
     }else if(currentY < lastY){
         // moved up
     }
     lastY = currentY;
});