微信小程序 列表左滑动删除

列表左滑动删除

wxml

view的事件处理

• bindtouchstart (手指触摸动作开始)
• bindtouchmove( 手指触摸后移动)
• bindtouchend(手指触摸动作结束)
• tap(手指触摸后马上离开)
• longtap(手指触摸后，超过350ms再离开)

<view class="item-box">

  <view class="items">
    <view wx:for="{{list}}" wx:key="{{index}}" class="item">
      <view bindtouchstart="touchS" bindtouchmove="touchM" bindtouchend="touchE" data-index="{{index}}" style="{{item.txtStyle}}" class="inner txt">

        <image class="item-icon" mode="widthFit" src="{{item.img}}"> </image>
        {{item.title}}

      </view>

      <view data-index="{{index}}" bindtap="delItem" class="inner del">删除</view>
    </view>
  </view>
</view>

js

var util = require('../../utils/pulldown.js')

Page({
  data: {
    delBtnWidth: 180 //删除按钮宽度单位（rpx）
  },
  onLoad: function(options) {
    // 页面初始化 options为页面跳转所带来的参数
    this.initEleWidth();
    this.tempData();
  },

  // 页面渲染完成
  onReady: function() {
  },
  // 页面显示
  onShow: function() {
  },
   // 页面隐藏
  onHide: function() {
  },
    // 页面关闭
  onUnload: function() {
  },

  touchS: function(e) {
    console.log('e.touches = ' + e.touches);
    if (e.touches.length == 1) {
      this.setData({
        //设置触摸起始点水平方向位置
        startX: e.touches[0].clientX
      });
    }
  },

  touchM: function(e) {
    if (e.touches.length == 1) {
      //手指移动时水平方向位置
      var moveX = e.touches[0].clientX;
      //手指起始点位置与移动期间的差值
      var disX = this.data.startX - moveX;
      var delBtnWidth = this.data.delBtnWidth;
      var txtStyle = "";
      if (disX == 0 || disX < 0) { //如果移动距离小于等于0，文本层位置不变
        txtStyle = "left:0px";
      } else if (disX > 0) { //移动距离大于0，文本层left值等于手指移动距离
        txtStyle = "left:-" + disX + "px";
        if (disX >= delBtnWidth) {
          //控制手指移动距离最大值为删除按钮的宽度
          txtStyle = "left:-" + delBtnWidth + "px";
        }
      }
      //获取手指触摸的是哪一项
      console.log("e.target.dataset = " + e.target.dataset);
      var index = e.target.dataset.index;
      var list = this.data.list;
      if (index >= 0) {
        list[index].txtStyle = txtStyle;
        //更新列表的状态
        this.setData({
          list: list
        });
      }
    }
  },

  touchE: function(e) {
    if (e.changedTouches.length == 1) {
      //手指移动结束后水平位置
      var endX = e.changedTouches[0].clientX;
      //触摸开始与结束，手指移动的距离
      var disX = this.data.startX - endX;
      var delBtnWidth = this.data.delBtnWidth;
      //如果距离小于删除按钮的1/2，不显示删除按钮
      var txtStyle = disX > delBtnWidth / 2 ? "left:-" + delBtnWidth + "px" : "left:0px";
      //获取手指触摸的是哪一项
      var index = e.target.dataset.index;
      var list = this.data.list;
      console.log(e);
      if (index >= 0) {
        list[index].txtStyle = txtStyle;
        //更新列表的状态
        this.setData({
          list: list
        });
      }
    }
  },

  //获取元素自适应后的实际宽度
  getEleWidth: function(w) {
    var real = 0;
    try {
      var res = wx.getSystemInfoSync().windowWidth;
      var scale = (750 / 2) / (w / 2); //以宽度750px设计稿做宽度的自适应
      // console.log(scale);
      real = Math.floor(res / scale);
      return real;
    } catch (e) {
      return false;
      // Do something when catch error
    }
  },
  initEleWidth: function() {
    var delBtnWidth = this.getEleWidth(this.data.delBtnWidth);
    this.setData({
      delBtnWidth: delBtnWidth
    });
  },

  //点击删除按钮事件
  delItem: function(e) {
    //获取列表中要删除项的下标
    var index = e.target.dataset.index;
    var list = this.data.list;
    //移除列表中下标为index的项
    list.splice(index, 1);
    //更新列表的状态
    this.setData({
      list: list
    });
  },
  
  //获取数据
  tempData: function() {
    let that = this;
    let searchKeyword = '', //输入框字符串作为参数
      searchPageNum = 1, //把第几次加载次数作为参数
      callbackcount = 20; //返回数据的个数
    var mlist = [];
    //访问网络
    util.getSearch(searchKeyword, searchPageNum, callbackcount, function(data) {
      const length = data.d.length;
      for (let i = 0; i < length; i++) {
        console.log('i = ' + data.d[i].title);
        let info = {
          title: data.d[i].title,
          desc: data.d[i].desc,
          profile: data.d[i].profile,
          img: data.d[i].img,
          txtStyle: "",
        }
        
        mlist.push(info);
      }

      that.setData({
        list: mlist
      });
      console.log("list = " + that.data.list);
    });

   
  }

})

pulldown.js

function getSearch(keyword, pageindex, callbackcount, callback) {
  wx.request({
    url: 'https://xiaoce-timeline-api-ms.juejin.im/v1/getListByLastTime?pageNum=' + pageindex,
    data: [],
    method: 'GET',
    header: {
      'content-Type': 'application/json'
    },
    success: function(res) {
      if (res.statusCode == 200) {
        callback(res.data);
      }
    }
  })
}

module.exports = {
  getSearch: getSearch
}

wxss

view {
  box-sizing: border-box;
}

.item-box {
  width: 700rpx;
  margin: 0 auto;
  padding: 40rpx 0;
}

.items {
  width: 100%;
}

.item {
  position: relative;
  border-top: 2rpx solid #eee;
  height: 180rpx;
  line-height: 180rpx;
  overflow: hidden;
}

.item:last-child {
  border-bottom: 2rpx solid #eee;
}

.inner {
  position: absolute;
  top: 0;
}

.inner.txt {
  background-color: #fff;
  width: 100%;
  z-index: 5;
  padding: 0 10rpx;
  transition: left 0.2s ease-in-out;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  /* overflow-wrap: break-word; */
}

.item-txt {
  /* white-space: pre-line; */
  font-size: 12sp;
  line-height:150rpx;
}

.inner.del {
  background-color: #e64340;
  width: 180rpx;
  text-align: center;
  z-index: 4;
  right: 0;
  color: #fff;
}

.item-icon {
  width: 120rpx;
  height: 150rpx;
  vertical-align: middle;
  margin-right: 10rpx;
  margin-left: 10rpx;
}

.thumb {
  width: 200px;
  height: 200px;
  -webkit-overflow-scrolling: touch;
  overflow: scroll;
}

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