flutter lifecycle_error ai_generated true

Looking up a deactivated widget's ancestor is unsafe.

ID: flutter/build-context-deactivated

Also available as: JSON · Markdown
85%Fix Rate
89%Confidence
3Evidence
2023-01-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
3 active — — —

Root Cause

BuildContext used after the widget has been removed from the tree. Commonly occurs when navigating or showing dialogs from async callbacks.

generic

Workarounds

  1. 92% success Check mounted before using context after an await 
    await someAsyncOp(); if (!mounted) return; Navigator.of(context).push(...);

    Sources: https://api.flutter.dev/

  2. 88% success Use a NavigatorKey or router at the app level for navigation from async code 
    final navigatorKey = GlobalKey<NavigatorState>(); // set on MaterialApp, use navigatorKey.currentState!.push(...)
  3. 85% success Move async logic to a provider/bloc and react to state changes in the widget 
    Widget listens to state stream and navigates in build/listener, not in async callback

Dead Ends

Common approaches that don't work:

  1. Store BuildContext in a variable and use it later in async code 82% fail

    Context becomes invalid after the widget is deactivated; storing it does not keep it alive

  2. Use a GlobalKey to get context from anywhere 70% fail

    GlobalKey.currentContext can also be null after widget disposal; same lifecycle issue