微信小程序实现滑动删除效果

最初打算使用scroll-view实现，效果好、流畅、有惯性滑动，但由于滚动条没法去掉、无法实现上下层的帧布局，最终放弃了。

还是自己写个吧，利用手势事件。遗憾的是小程序中目前没有像Android中快速滑动事件，所以，要实现惯性滑动是不可能了。

item的布局：

推荐小程序优先使用flex布局，完全够用。这也是微信推荐的。

<view wx:for="{{cardTeams}}" wx:for-item="cardTeam" id="{{cardTeam.id}}" class="item" bindtouchstart="drawStart" bindtouchmove="drawMove" bindtouchend="drawEnd" style="right:{{cardTeam.right}}px"> 
    <image class="img" src="http://img02.tooopen.com/images/20150928/tooopen_sy_143912755726.jpg" mode="scaleToFill"></image> 
    <view class="number-wrapper"> 
     <text class="name">{{cardTeam.name}}</text> 
     <view class="count-wrapper"> 
      <view class="decrease-btn">-</view> 
      <text class="count">1</text> 
      <view class="increase-btn">+</view> 
     </view> 
     <view class="price-wrapper"> 
      <text class="unit">¥</text> 
      <text class="price">99.80</text> 
     </view> 
    </view> 
    <view class="ok"><view class="inner-ok">确定</view></view> 
    <view class="remove" data-id="{{cardTeam.id}}" bindtap="delItem"><view>删除</view></view> 
   </view>

主要是将删除按钮的设为绝对定位(position: absolute)：

.item .remove{ 
  width: 60px; 
  height: 100%; 
  background-color: red; 
  position: absolute; 
  top: 0; 
  right: -60px; 
  display: flex; 
  justify-content: center; 
  align-items: center; 
}

Page({ 
 data: { 
  cardTeams:[{"id":"aaaaa", "name":"android教程", "url":"http://www.see-source.com", "right":0, "startRight":0},{"id":"bbbb", "name":"小程序教程", "url":"http://www.see-source.com", "right":0, "startRight":0}] 
 }, 
 drawStart : function(e){ 
   // console.log("drawStart"); 
  var touch = e.touches[0]; 
  startX = touch.clientX; 
  startY = touch.clientY; 
  var cardTeams = this.data.cardTeams; 
  for(var i in cardTeams){ 
    var data = cardTeams[i]; 
    data.startRight = data.right; 
  } 
  key = true; 
 }, 
 drawEnd : function(e){ 
  console.log("drawEnd"); 
  var cardTeams = this.data.cardTeams; 
  for(var i in cardTeams){ 
    var data = cardTeams[i]; 
    if(data.right <= 100/2){ 
      data.right = 0; 
    }else{ 
      data.right = maxRight; 
    } 
  } 
  this.setData({ 
    cardTeams:cardTeams 
  }); 
 }, 
 drawMove : function(e){ 
   //console.log("drawMove"); 
  var self = this; 
  var dataId = e.currentTarget.id; 
  var cardTeams = this.data.cardTeams; 
  if(key){ 
    var touch = e.touches[0]; 
    endX = touch.clientX; 
    endY = touch.clientY; 
    console.log("startX="+startX+" endX="+endX ); 
    if(endX - startX == 0) 
      return ; 
    var res = cardTeams; 
      //从右往左 
 
      if((endX - startX) < 0){ 
        for(var k in res){ 
          var data = res[k]; 
          if(res[k].id == dataId){ 
            var startRight = res[k].startRight; 
            var change = startX - endX; 
            startRight += change; 
            if(startRight > maxRight) 
              startRight = maxRight; 
            res[k].right = startRight; 
          } 
        } 
      }else{//从左往右 
        for(var k in res){ 
          var data = res[k]; 
          if(res[k].id == dataId){ 
            var startRight = res[k].startRight; 
            var change = endX - startX; 
            startRight -= change; 
            if(startRight < 0) 
              startRight = 0; 
            res[k].right = startRight ; 
          } 
        } 
      } 
      self.setData({ 
        cardTeams:cardTeams 
      }); 
           
  } 
 }, 
 //删除item 
 delItem: function(e){ 
  var dataId = e.target.dataset.id; 
  console.log("删除"+dataId); 
  var cardTeams = this.data.cardTeams; 
  var newCardTeams = [];  
  for(var i in cardTeams){ 
    var item = cardTeams[i]; 
    if(item.id != dataId){ 
     newCardTeams.push(item); 
    } 
  } 
  this.setData({ 
    cardTeams:newCardTeams 
   }); 
 }, 
 onLoad: function () { 
  console.log('onLoad:'+app.globalData.domain) 
   
 } 
})

drawStart用于记录手指触碰时的位置，drawMove记录手指滑动的位置，两者的差值就是删除按钮的偏移量
drawEnd手指抬起时触发，用于设置弹回、摊开效果。目前我的是超过一半自动弹开，不足一半自动收回。