微信小程式左滑效果

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title: 微信小程式左滑效果 date: 2018-03-28 12:07:27 tags:

html

<view class="container">
  <view class="touch-item {{item.isTouchMove ? 'touch-move-active' : ''}}" data-index="{{index}}" bindtouchstart="touchstart" bindtouchmove="touchmove" wx:for="{{items}}" wx:key="{{index}}">
    <view class="content">{{item.content}}</view>
    <view class="del" catchtap="del" data-index="{{index}}">刪除</view>
  </view>
</view>

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CSS

.touch-item {
  font-size: 14px;
  display: flex;
  justify-content: space-between;
  border-bottom:1px solid #ccc;
  width: 100%;
  overflow: hidden
}
.content {
  width: 100%;
  padding: 10px;
  line-height: 22px;
  margin-right:0;
  -webkit-transition: all 0.4s;
  transition: all 0.4s;
  -webkit-transform: translateX(90px);
  transform: translateX(90px);
  margin-left: -90px
}
.del {
  background-color: orangered;
  width: 90px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  color: #fff;
  -webkit-transform: translateX(90px);
  transform: translateX(90px);
  -webkit-transition: all 0.4s;
  transition: all 0.4s;
}
.touch-move-active .content,
.touch-move-active .del {
  -webkit-transform: translateX(0);
  transform: translateX(0);
}
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JS

var app = getApp()
Page({
  data: {
    items: [],
    startX: 0, //開始座標
    startY: 0
  },
  onLoad: function () {
    for (var i = 0; i < 10; i++) {
      this.data.items.push({
        content: i + " 向左滑動刪除哦,向左滑動刪除哦,向左滑動刪除哦,向左滑動刪除哦,向左滑動刪除哦",
        isTouchMove: false //預設全隱藏刪除
      })
    }
    this.setData({
      items: this.data.items
    })
  },
  //手指觸控動作開始 記錄起點X座標
  touchstart: function (e) {
    //開始觸控時 重置所有刪除
    this.data.items.forEach(function (v, i) {
      if (v.isTouchMove)//只操作為true的
        v.isTouchMove = false;
    })
    this.setData({
      startX: e.changedTouches[0].clientX,
      startY: e.changedTouches[0].clientY,
      items: this.data.items
    })
  },
  //滑動事件處理
  touchmove: function (e) {
    var that = this,
      index = e.currentTarget.dataset.index,//當前索引
      startX = that.data.startX,//開始X座標
      startY = that.data.startY,//開始Y座標
      touchMoveX = e.changedTouches[0].clientX,//滑動變化座標
      touchMoveY = e.changedTouches[0].clientY,//滑動變化座標
      //獲取滑動角度
      angle = that.angle({ X: startX, Y: startY }, { X: touchMoveX, Y: touchMoveY });
    that.data.items.forEach(function (v, i) {
      v.isTouchMove = false
      //滑動超過30度角 return
      if (Math.abs(angle) > 30) return;
      if (i == index) {
        if (touchMoveX > startX) //右滑
          v.isTouchMove = false
        else //左滑
          v.isTouchMove = true
      }
    })
    //更新資料
    that.setData({
      items: that.data.items
    })
  },
  /**
   * 計算滑動角度
   * @param {Object} start 起點座標
   * @param {Object} end 終點座標
   */
  angle: function (start, end) {
    var _X = end.X - start.X,
      _Y = end.Y - start.Y
    //返回角度 /Math.atan()返回數字的反正切值
    return 360 * Math.atan(_Y / _X) / (2 * Math.PI);
  },
  //刪除事件
  del: function (e) {
    this.data.items.splice(e.currentTarget.dataset.index, 1)
    this.setData({
      items: this.data.items
    })
  }
})
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