<block wx:for="{{nums}}" wx:for-index=\'key\' wx:for-item=\'item\'>

  <view class="maxbox"  bindtap="imgchange"  id="{{key}}">
    <text class="nums">{{item.num}}</text>
  </view>

</block>

Page({  
    data: {
      nums:[
        {num:11},
        {num:22}
      ]
    }, 
    imgchange: function (event) {
      //获取当前item的下标id  通过currentTarget.id
      var id = event.currentTarget.id;
        console.log(id);
      var nums = this.data.nums[id].num;
      console.log(nums);

    },
})