预览图片功能 直接复制就OK

wx.js

 previewImage(val) {
    let result=val.currentTarget.dataset.item;
    const that = this;
    wx.previewImage({
      current: result, // 当前显示图片的http链接
      urls: that.data.homeList.imagesUrl // 需要预览的图片http链接列表
    })
  },

wx.ml

        <block wx:for="{{homeList.imagesUrl}}">
                        <view class="upload_item" wx:key="{{index}}">
                            <image src="{{item}}" class="img" alt="" data-item="{{item}}" bindtap="previewImage" />
                        </view>
         </block>