支付宝小程序实现折叠面板（panel）

需要实现的功能效果如下

axml文件代码

    <view class="help-item" a:for="{{helpList}}"  key="{{index}}">
      <view class="help-title" onTap="clickHandle" data-index='{{index}}'>
        <view class="title-text">{{item.helpTitle}}</view>
        <view class="title-arrow">
          <text class="iconfont {{showIndex == index ? 'icon-down':'icon-right'}}"></text>
        </view>
      </view>
      <view class="help-content" a:if="{{showIndex == index}}">
        {{item.helpContent}}
      </view>
    </view>

js文件内容

Page({
  data: {
    helpList:[
      {
        helpTitle:"item-title1",
        helpContent:"item-content1"
      },
        {
        helpTitle:"item-title2",
        helpContent:"item-content2"
      },
        {
        helpTitle:"item-title3",
        helpContent:"item-content3"
      }
      
    ],
    showIndex:"-1"
  },
  clickHandle(e){
    console.log(e.currentTarget.dataset.index);
    if (e.currentTarget.dataset.index != this.data.showIndex) {
      this.setData({
        showIndex: e.currentTarget.dataset.index
      })
    } else {
      this.setData({
        showIndex: "-1"
      })
    }
  }
});