有没有办法让小部件在颤动中等待小部件的结果

如何解决有没有办法让小部件在颤动中等待小部件的结果

我试图将 resultMsg 的值从 FutureBuilder 小部件传递给 Text 小部件，但它仍然给我变量的初始值，有没有办法在之前构建第一个小部件，获取变量更改（这是全局变量）并通过它？ 或任何其他方式 IM 发布我的代码以显示我要求的变量

 child: ListView(
        shrinkWrap: true,children: <Widget>[
          Container(
              height: 400,child: SafeArea(
                child: FutureBuilder(
                    future: _getdeptemp(),builder: (context,snapshot) {
                      if (snapshot.hasData) {
                        int x = (snapshot.data.length);
                        double xx = double.parse(x.toString());
                       //some process
                        resultMsg = ""+Sum ; //*********here is the value I want to assign variable to it************** 
                           
                 return
                        
                         new  charts.LineChart(
                          seriesList(dataa),animate: false,behaviors: [
                            new charts.ChartTitle('Session number',behaviorPosition:
                                    charts.BehaviorPosition.bottom,//titleStyleSpec: charts.TextStyleSpec(fontSize: 14),titleOutsideJustification: charts
                                    .OutsideJustification.middleDrawArea),new charts.ChartTitle(
                                'Right Pose Percentage,%',behaviorPosition:
                                    charts.BehaviorPosition.start,//titleStyleSpec: chartsCommon.TextStyleSpec(fontSize: 11),titleOutsideJustification: charts
                                    .OutsideJustification.middleDrawArea)
                          ],);
                      } else {
                        return Center(child: CircularProgressIndicator());
                      }
                    }),)),Container(
             
              child: new Text(
                resultMsg,//////here is the variable ******
                style: TextStyle(
                  color: Colors.black,fontSize: 16,),],

解决方法

如果你想在其他Widget上使用FutureBuilder的数据值，
你把那个 Widget 插入到 FutureBuilder 里面怎么样？

在您的情况下，您需要通过 Column Widget 包装 LineChart 和 Container 小部件。

I just suggest but I don't know whether the error is because I don't have all source.
<As-is>
-ListView
--FutureBuilder
---LineChart
--Container
---Text

<To-be>
-ListView
--FutureBuilder
---Column
----LineChart
----Container
-----Text

or

-FutureBuilder
--ListView
---LineChart
---Container
----Text

这里是基于您的代码的建议代码，例如“To-be”。

ListView(
        shrinkWrap: true,children: <Widget>[
          Container(
              height: 400,child: SafeArea(
                child: FutureBuilder(
                    future: _getdeptemp(),builder: (context,snapshot) {
                      if (snapshot.hasData) {
                        int x = (snapshot.data.length);
                        double xx = double.parse(x.toString());
                       //some process
                        resultMsg = ""+Sum ; //*********here is the value I want to assign variable to it************** 
                         return Column(
                           children: [
                            new  charts.LineChart(
                              seriesList(dataa),animate: false,behaviors: [
                                new charts.ChartTitle('Session number',behaviorPosition:
                                    charts.BehaviorPosition.bottom,//titleStyleSpec: charts.TextStyleSpec(fontSize: 14),titleOutsideJustification: charts
                                    .OutsideJustification.middleDrawArea),new charts.ChartTitle(
                                  'Right Pose Percentage,%',behaviorPosition:
                                    charts.BehaviorPosition.start,//titleStyleSpec: chartsCommon.TextStyleSpec(fontSize: 11),titleOutsideJustification: charts
                                    .OutsideJustification.middleDrawArea)
                              ],),Container(
                              child: new Text(
                                resultMsg,//////here is the variable ******
                                style: TextStyle(
                                  color: Colors.black,fontSize: 16,],);
                      } else {
                        return Center(child: CircularProgressIndicator());
                      }
                    }),)),);