有没有办法在jQuery或Javascript中确定touchmove事件的速度？

Question

这是一个简单的问题.有没有办法在jQuery或Javascript中确定touchmove事件的速度？我使用css来抓取元素并让它可以抓取,这样可以正常但是如果我更快地移动手指,我不太可能移动到阈值距离但我确实打算翻页,所以有没有办法我可以确定javascript或jQuery中触摸移动事件的移动速度,我可以将阈值调整为较小的值以补偿速度？

    var startX, endX, difference, threshold; 
var startTime, endTime, timeDiff = 151;
$('#animate')
.bind("touchstart", function (e){ 
    e.preventDefault();
    var d = new Date();      
    startTime = d.getTime();
    startX = e.originalEvent.touches[0].pageX; //starting point
    })
.bind("touchmove", function (e){
    e.preventDefault();
    endX =e.originalEvent.changedTouches[0].pageX; //Get the information for finger 
    difference = startX - endX;  //calculate the distance moved.
    var moved = minusScreen - difference; //determine the affected css value.
    $(this).css("left",moved);  //this makes the element moves with my finger.
    })
.bind("touchend", function (e) { 
    var date = new Date();
    endTime = date.getTime();
    threshold = Math.abs(difference);
    timeDiff = endTime - startTime;
    if ((threshold > (screenWidth * 0.4)) || (timeDiff < 150))  //make the animation move only when the finger moved more than 30% of the page.
        {           
        if (endX > startX) turnLeft();
        else if (endX == startX) {} // havent decide what to do yet 
        else turnRight();
    } else {
        $(this).animate({"left": minusScreen}, 100);
    }
    startX=0; //set the value back to initial.
    endX=0;   //set the value back to initial.});
    });

谢谢你的回答.以上是修改后的代码.工作得很好!!!

Answer 1

在touchstart上获得时间,再次在这样的touchend上

startTime = new Date().getTime() 和 endTime = new Date().getTime()

然后计算var speed = abs(endX-startX)/(endTime-startTime)这是你的整体触摸速度,以px/ms为单位