anchor.diff:                ?.call(Size(layoutKey.currentContext.size.width, widgetHeight));
           }
         }
  -
  -
       });
     }
   
  
positive.code:           layoutTopicContainerKey.currentContext?.findRenderObject();
  
        var dy = renderBox2
            ?.localToGlobal(Offset.zero,
                ancestor: layoutKey.currentContext.findRenderObject())
            ?.dy ?? 0;
        var sizeTagContainer = layoutTopicContainerKey?.currentContext?.size ?? null;
        var headerSize = layoutKey?.currentContext?.size;
        if(dy > 0 && headerSize != null && sizeTagContainer != null) {
          /// 20是 card 的上下 padding
          var newSize = dy + sizeTagContainer.height + 20;
          if (widgetHeight != newSize && newSize > 0) {
  
negative.code:                 child: new Column(
                    mainAxisSize: MainAxisSize.min,
                    children: <Widget>[
                      _renderTopNameInfo(),
                      _renderSubInfo(),
  
                      ///仓库描述
                      renderDes(),
  
                      ///创建状态
                      renderRepoStatus(),
                      new Divider(
                        color: GSYColors.subTextColor,
                      ),
  
                      ///底部信息
                      renderBottomInfo(),
  
                      ///底部tag
                      _renderTopicGroup(context),
                    ],
                  ),
  