dart - 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.

代码:

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

class RouteHome extends StatefulWidget {
  RouteHome({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

查询:

• 为什么不允许 StatefulWidget 使用它？

---

问题:如果小部件的基类更改(StatefulWidget <-> StatelessWidget)，则路由热重载失败。

Answer 1

热重载仅用于最小的 UI 更改。

礼貌:“这不是问题，使用热重载对 UI 进行最小的更改。通常你需要在创建新类(class)时完全重启。” – @aziza