alt*_*ve4 9 dart flutter flutter-layout
网站上有一些类似的问题,但我无法准确弥补
Widget _buildBody(tab) {
return BlocBuilder(
bloc: _lessonsBloc,
builder: (BuildContext context, LessonsState state) { //HERE
if (state is LessonsLoading) {
return Center(
child: CircularProgressIndicator(),
);
} else if (state is LessonsLoaded) {
return ListView.builder(
itemCount: state.lessons.length,
itemBuilder: (context, index) {
final displayedLessons = state.lessons[index];
return ListTile(
title: Text(displayedLessons.name),
subtitle:Text(displayedLessons.subname),
trailing: _buildUpdateDeleteButtons(displayedLessons),
);
},
);
}
},
);
}
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这是我的代码,我在 builder 所在的标题中收到警告。
如果有人提供解决方案或想法,我将不胜感激:)
Cop*_*oad 11
您需要从build()
方法中返回小部件,但您错过了一个案例。
Widget _buildBody() {
return BlocBuilder(
bloc: _lessonsBloc,
builder: (BuildContext context, LessonsState state) {
if (state is LessonsLoading) {
return Widget1();
} else if (state is LessonsLoaded) {
return Widget2();
}
return CircularProgressIndicator(); // You missed this return statement.
},
);
}
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