Synchronous BuildContexts | Decoding Flutter
Why Stack Overflow recommends it
Stack Overflow users link it when answering questions about the 'Do not use BuildContexts across async gaps' lint, since it explains why the context may no longer be mounted after an await.
Recommended by 3 people across 2 different months, 2022 to 2025.
What it is
A short episode of the Flutter team's Decoding Flutter series explaining how Flutter's build process works and why a BuildContext can become invalid after an asynchronous gap or inside a button callback. It was made alongside the new use_build_contexts_synchronously lint.
What people said
Recommends Louise · 2022-08 · Stack Overflow · on “Why can't I use BuildContext after await in an async function?”
A helpful video by the Flutter team was apparently posted one month after posting my question. To summarize, the widget's corresponding element has unpredictable moments in which it would refresh, causing the BuildContext to change. The BuildContext in this case being the widget's element. The following is the Flutter team's explanation about it. The more dramatically your widget tree changes from one frame to the next, the more likely Flutter is in need to update portions of your element tree. And for every new frame, it's always possible that a given widget's element has been removed from the tree. Unpredictable events from your user can force Flutter to reassemble the element tree at any
Recommends venir · 2022-08 · Stack Overflow · on “BuildContexts across Async gaps, what is the alternative to this?”
Your IDE is showing a lint advice, which isn't necessarily a build time error; nonetheless, this lint is telling you there's a good chance that your code will throw a runtime error. Why? This video [this video] does a pretty good job answering it. There's a good chance you just need a if (mounted) check to fix this.
Recommends venir · 2022-08 · Stack Overflow · on “The cause of this error is needed mounted but i cannot call mounted in here”
Your IDE is showing a lint advice, which is not a build time error; nonetheless, this lint is telling you there's a good chance that your code will throw a runtime error. Why? Well, I guess this video [this video] does a pretty good job answering it. As the video suggests, there are many ways to work around that.If you've understood the problem explained in the video, read this usefeul Tweet [LINK] from the creator of Provider (and Riverpod) himself to have more intel onto this lint. Finally, a straight answer to fix your code depends on your use case, as Remi said in the tweet. Provide more context (e.g. where is this function located at) and clearly type your question if you want a clear answer
Recommends Dhruvin Vainsh · 2023-09 · Stack Overflow · on “Trying to use Build Context across async gaps in flutter”
It simply means that the context that you are using for the scoping you provided might have disposed after/before your async call so it may throw an error as this Element would not be part of the tree and so it won't be able to scope particularly Provider . For more details on how the scoping( .of ) of the provider works you can head to this question's answer [LINK] . For a detailed explanation of the async context you can head to this [this video] official video on Flutter dev's youtube handle.
Cites Md. Yeasin Sheikh · 2022-09 · Stack Overflow · on “Flutter "Do not use BuildContexts across async gaps"”
It is unsafe, try checking if the widget is not mounted as shown on the Flutter YouTube Channel [this video] . if (!mounted) return Navigator.of(context);
Cites john · 2022-11 · Stack Overflow · on “Do not use BuildContexts across async gaps lint error on presenter layer”
after an async gap, there is a possibility that your widget is no longer mounted. thats why context is not recommended to use across an async gap. But if you are so sure that your widget is still mounted then, according to flutter team which you can check here [this video] , the recommended approach is to store the context before the await keyword. In your case, this is how it should be done: Future<void> login(BuildContext context,String username, String password) async { final nav = Navigator.of(context); showDialog(context); var result = await authenticate(username,password); int type = await getUserType(result); nav.pop(); // to hide progress dialog if(type == 1){ nav.pushReplacementNamed('a'
Cites YujiSoftware · 2025-07 · Stack Overflow · on “How to call snackbar inside async method?”
Before async, get the ScaffoldMessenger. var messanger = ScaffoldMessenger.of(context); await Future.delayed(const Duration(second: 1)); messanger.showSnackBar(snackBar); See: Synchronous BuildContexts | Decoding Flutter [this video]