为什么StatefulWidget的路由创建失败？

Question

我正在尝试使用StatefulWidget创建路由。

错误：

I/flutter (23141): ??? EXCEPTION CAUGHT BY WIDGETS LIBRARY ????????????????????????????????????????????????????????????
I/flutter (23141): The following assertion was thrown building
I/flutter (23141): _OverlayEntry-[LabeledGlobalKey<_OverlayEntryState>#3e9ee](dirty, state: _OverlayEntryState#7b90c):
I/flutter (23141): The builder for route "/" returned null.
I/flutter (23141): Route builders must never return null.

码：

routes:<String,WidgetBuilder>{
        "/":(_)=>new RouteHome(title: 'Flutter Demo Home Page'),
        ...

I/flutter (23141): ??? EXCEPTION CAUGHT BY WIDGETS LIBRARY ????????????????????????????????????????????????????????????
I/flutter (23141): The following assertion was thrown building
I/flutter (23141): _OverlayEntry-[LabeledGlobalKey<_OverlayEntryState>#3e9ee](dirty, state: _OverlayEntryState#7b90c):
I/flutter (23141): The builder for route "/" returned null.
I/flutter (23141): Route builders must never return null.

查询：

• 为什么不允许StatefulWidget？

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问题： 如果更改了窗口小部件的基类（StatefulWidget <-> StatelessWidget），则路由的热重装失败。

Answer 1

热重装仅用于最小的UI更改。

礼貌： “这不是问题，使用热重载可以在UI中进行最小的更改。通常，在创建新类时需要完全重新启动。” – @aziza