微信小程序实现点击图片放大预览

 <view class='topic_answerImg'>
  
 <block wx:for='{{item.answerImg}}' wx:key='index' wx:for-item='answerItem'>
 <image bindtap='topic_preview' data-id='{{item.id}}' data-url='{{answerItem}}' class='topic_answer_itemImg' src='{{answerItem}}'></image>
 </block>
 
</view>

.topic_answerImg{
 width: 100%;
 display: -webkit-box;
 display: -webkit-flex;
 flex-wrap: wrap;
}
.topic_answer_itemImg{
 width: 210rpx;
 height: 210rpx;
 margin-right: 30rpx;
 margin-bottom: 30rpx;
}
.topic_answer_itemImg:nth-of-type(3n){
 margin-right: 0;
}

 //预览图片
 topic_preview: function(e){
 var that = this;
 var id = e.currentTarget.dataset.id;
 var url = e.currentTarget.dataset.url;
 var previewImgArr = [];
 //通过循环在数据链里面找到和这个id相同的这一组数据，然后再取出这一组数据当中的图片
 var data = that.data.topic_recomData;
 for (var i in data) {
 if (id == data[i].id) {
 previewImgArr = data[i].pic;
 }
 }
 wx.previewImage({
 current: url, // 当前显示图片的http链接
 urls: previewImgArr // 需要预览的图片http链接列表
 })
 },