如何在小部件构建期间在颤动中导航？

Question

我试图检测该用户不再经过身份验证并将用户重定向到登录。这就是我的做法

  Widget build(BuildContext context) {
    return FutureBuilder(
        future: _getData(context),
        builder: (context, snapshot) {
          try {
            if (snapshot.hasError && _isAuthenticationError(snapshot.error)) {
                Navigator.push(context, MaterialPageRoute(builder: (context) => LoginView()));
            }

不幸的是，在构建时进行导航不起作用。它抛出这个错误

flutter: setState() or markNeedsBuild() called during build.
flutter: This Overlay widget cannot be marked as needing to build because the framework is already in the
flutter: process of building widgets.  A widget can be marked as needing to be built during the build 

我不能只返回LoginView小部件，因为父小部件包含应用栏和浮动按钮，并且需要在没有这些控件的情况下显示登录视图。我需要导航。

有可能做到吗？

Answer 1

把它包起来Future.microtask。这将安排它在下一个异步任务周期（即build完成后）发生。

Future.microtask(() => Navigator.push(
  context, 
  MaterialPageRoute(builder: (context) => LoginView())
));