我如何从滑动检测中获得负数？

Question

我有一个名为x的变量，它将作为起点，myCount用于计数用户进行的每一次滑动，最后一个变量dist返回一个特定数字，该数字距起点有多远点。

如果myCount将要在-201之下由用户向移动到左侧（在移动设备中滑动），我想在dist中存储-1。

存储正数可以正常工作（通过向右拖动），但是从不存储负数。

是否有解决此问题的解决方案？

这是我到目前为止所做的：

CodePen

$(function stripeAnimeModule() {
  // Variables
    var screen = $('.page1'),
    buttons = $('.buttons').find('.button'),
    myCount = 1,
    x,
    dist;
  // Functions
    function clicked(e) {
      if ($(this).hasClass('prev')) {
        myCount -= 1;
        console.log(myCount, 'this is clicked');
      } else {
        myCount += 1;
        console.log(myCount);
      }
    }
    function touchStart(e) {
      return x = e.touches[0].pageX;
      e.preventDefault();
    }
    function touchMove(e) {
      var drag = e.touches[0].pageX;
      var dist = Math.sqrt(x + drag);
      e.preventDefault();
    }
    function touchEnd(e) {
      var dist = e.changedTouches[0].pageX - x;
      if (dist < Math.abs(-200)) {
        myCount = myCount;
        console.log('nothing', dist, myCount);
      } else if (dist > 201) {
        myCount += 1;
        console.log('distance is: ' + dist, x, 'myCount is: '+ myCount);
      } else if (dist > -201) {
        myCount -= 1;
        console.log('distance is: ' + dist, x, 'myCount is: '+ myCount);
      }
      e.stopPropagation();
      e.preventDefault();
    }
    buttons.on({click: clicked});
    screen.bind({touchstart:touchStart, touchmove:touchMove, touchend: touchEnd});
})

* {
  margin: 0;
  padding: 0;
}
ul li {
  list-style: none;
}
a {
  display: block;
}
.page1 {
  position: absolute;
  width: 100vw;
  height: 100vh;
  background-color: grey;
}
.buttons {
  z-index: 1;
}
.prev {
  position: absolute;
  left: 0;
  margin: 0 40px;
}
.shrink {
  position: absolute;
}
.next {
  position: absolute;
  right: 0;
  margin: 0 40px;
}

<div class="page1" href="#"></div>
<ul class="buttons">
  <li class="button prev">Prev</li>
  <li class="shrink"></li>
  <li class="button next">Next</li>
</ul>
<br><br><br><br><br><br><br><br><br><br><br><br><br>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

Answer 1

$(function stripeAnimeModule() {
  // Variables
    var screen = $('.page1'),
    buttons = $('.buttons').find('.button'),
    myCount = 1,
    x,
    dist;
  // Functions
    function clicked(e) {
      if ($(this).hasClass('prev')) {
        myCount -= 1;
        console.log(myCount, 'this is clicked');
      } else {
        myCount += 1;
        console.log(myCount);
      }
    }
    function touchStart(e) {
      return x = e.touches[0].pageX;
      e.preventDefault();
    }
    function touchMove(e) {
      var drag = e.touches[0].pageX;
      var dist = Math.sqrt(x + drag);
      e.preventDefault();
    }
    function touchEnd(e) {
      var dist = e.changedTouches[0].pageX - x;
      if (dist > 201) {
        myCount += 1;
        console.log('distance is: ' + dist, x, 'myCount is: '+ myCount);
      } else if (dist < -201) {
        myCount -= 1;
        console.log('distance is: ' + dist, x, 'myCount is: '+ myCount);
      } else {
        myCount = myCount;
        console.log('nothing', dist, myCount);
      }
      e.stopPropagation();
      e.preventDefault();
    }
    buttons.on({click: clicked});
    screen.bind({touchstart:touchStart, touchmove:touchMove, touchend: touchEnd});
})

* {
  margin: 0;
  padding: 0;
}
ul li {
  list-style: none;
}
a {
  display: block;
}
.page1 {
  position: absolute;
  width: 100vw;
  height: 100vh;
  background-color: grey;
}
.buttons {
  z-index: 1;
}
.prev {
  position: absolute;
  left: 0;
  margin: 0 40px;
}
.shrink {
  position: absolute;
}
.next {
  position: absolute;
  right: 0;
  margin: 0 40px;
}

<div class="page1" href="#"></div>
<ul class="buttons">
  <li class="button prev">Prev</li>
  <li class="shrink"></li>
  <li class="button next">Next</li>
</ul>
<br><br><br><br><br><br><br><br><br><br><br><br><br>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

请看一下，让我知道这是否是您想要的。