Flutter：未处理的异常：查找已停用小部件的祖先是不安全的

Question

我正在尝试在特定持续时间后导航到某个页面。但是，每当我运行该应用程序时，我都会收到一条错误消息：At this point the state of the widget's element tree is no longer stable. To safely refer to a widget's ancestor in its dispose() method, save a reference to the ancestor by calling inheritFromWidgetOfExactType() in the widget's didChangeDependencies() method.

我的代码如下所示：

@override
void initState() {
  super.initState();
  googleSignIn.signInSilently(suppressErrors: false)
    .then((account) async {
      if (account != null) {
        List<Post> posts = await initTimelinePosts(account.id);
        List<String> followingList = await configureTimelineForNoPost(
          account.id
        );
        currentUser =
          User.fromDocument(await usersRef.document(account.id).get());
        Navigator.pushReplacement(
          context,
          MaterialPageRoute(
            builder: (context) => Home(
              posts: posts,
              followingList: followingList,
              savedState: widget.savedState
            )
          )
        );
      } else {
        Navigator.pushReplacement(
          context,
          MaterialPageRoute(
            settings: RouteSettings(name: Auth.route),
            builder: (context) => Auth(savedState: widget.savedState)
          )
        );
      }
    }).catchError((_) async {
      final SharedPreferences prefs = await SharedPreferences.getInstance();
      String userId = prefs.getString('userId');
      if (userId != null && userId.isNotEmpty) {
        DocumentSnapshot doc = await usersRef.document(userId).get();
        currentUser = User.fromDocument(doc);
        List<Post> posts = await initTimelinePosts(userId);
        List<String> followingList = await configureTimelineForNoPost(userId);
        Navigator.pushReplacement(
          context,
          MaterialPageRoute(
            builder: (context) => Home(
              posts: posts,
              followingList: followingList,
              savedState: widget.savedState,
            )
          )
        );
      } else {
        _timer = new Timer(
          Duration(milliseconds: 3000),
          () {
            Navigator.pushReplacement( // the error message points to this line
              context,
              MaterialPageRoute(
                settings: RouteSettings(name: Auth.route),
                builder: (context) => Auth(savedState: widget.savedState)
              )
            );
          }
        );
      }
    });
}

我希望应用程序能够正常运行，但事实并非如此。我该如何解决这个问题？

注意：我真的不知道该写什么了，所以一直抱怨我需要添加更多细节。我相信我已经对描述、标题和代码提供了足够的解释。

Answer 1

我认为问题在于您正在尝试导航到新页面并在 initState() 中替换此页面。由于运行 initState() 方法时未构建小部件树，因此可能会导致错误。

查看this answer 了解详细说明，查看this 了解类似问题。