我试图获取TextFormField值。但结果是null主页，children:[UrlTextField(),UsernameTextField(),UrlButton()]UrlTextField()，同UsernameTextField()classUrlTextFieldextendsStatelessWidget{finalmyController=TextEditingController();@overrideWidgetbuild(BuildContextcontext){returnAppTextField(decoration:InputDecoration(pre

我试图获取TextFormField值。但结果是null主页，children:[UrlTextField(),UsernameTextField(),UrlButton()]UrlTextField()，同UsernameTextField()classUrlTextFieldextendsStatelessWidget{finalmyController=TextEditingController();@overrideWidgetbuild(BuildContextcontext){returnAppTextField(decoration:InputDecoration(pre