我正在练习此代码

uj5u.com热心网友回复：

https://api.flutter.dev/flutter/widgets/StatefulWidget/createState.html

改变这个，

 class HomePage extends StatefulWidget{
              @override
                _HomePageState createSatate ()=> _HomePageState(); // change createSatate to createState
              }

到，

 class HomePage extends StatefulWidget{
              @override
                _HomePageState createState ()=> _HomePageState();
              }

uj5u.com热心网友回复：

class HomePage extends StatefulWidget{
  @override
  _HomePageState createSatate ()=> _HomePageState();
}

是因为笔误。

更改createSatate为createState。

您的 Homepage 类将如下所示

class HomePage extends StatefulWidget{
  @override
  _HomePageState createState ()=> _HomePageState();
}