我如何从滑动检测中获得负数？

Question

我有一个名为 x 的变量作为起点，myCount 用于计算用户完成的每次滑动，最后一个变量 dist returns 特定距离起点多远的数字。

如果 dist 将在 -201 下由用户拖动（在移动设备中滑动）到左侧，我想将 -1 存储在 myCount 中。

存储正数工作正常（通过拖动右侧），但它永远不会存储负数。

有解决这个问题的方法吗？

这是我到目前为止自己所做的：

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，如果这就是您要找的，请告诉我。