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">&yen;</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。