I am using provider for the state management on Flutter. I'm making async await function and have warning that Do not use BuildContexts across async gaps. So I tried to put 'if(!mounted)' code and I got warning that Undefined name 'mounted'.

How can I fix this problem? Thank you!

Provider codes

signIn(BuildContext context) async{
    try {
      final navigator = Navigator.of(context);
      !isSignupValid ? isSignupValid = true : null;
      await authentication.signInWithEmailAndPassword(
          email: userEmail.trim(), password: userPassword.trim()
      );
      navigator.pop();
    } on FirebaseAuthException catch (errorCode) {
      isSignupValid = false;
      print('isSignupValid : $isSignupValid');
      print('SignIn FirebaseAuthException : $errorCode');
      ScaffoldMessenger.of(context).showSnackBar(
        returnSnackBar(context, errorCode)
      );
    }
    await Future.delayed(const Duration(seconds: 0));
    if (!mounted) return;
    context.watch<ProfileData>().profileImage = null;
    notifyListeners();
  }

CodePudding user response：

The mounted property is only available in a StatefulWidget. If you are not in a stateful widget you have no way of knowing whether the context you are using still references the state of a widget which is still in the widget tree.

I'm not sure exactly what you do. You can either change your widget to a StatefulWidget or simply do a final profileData = context.read<ProfileData>() at the beginning of you method, and never access context after your first async call.