警报对话框：查找已停用小部件的祖先是不安全的

Question

In the code below, I am displaying a dialog box with a loader when the form is submitting, then on Error, dismissing the dialog box by popping from its context. However, Flutter is giving me that error as the context is no longer available after popping, but this doesn't break my app because I am recreating a context everytime a dialog box is shown. So, to improve my code, what can I do to fix this error?

End goal: Display loader on submission, if there is error, stop loader and display toast

** I know there is other solution like creating a global key for the scaffold, but I am looking for an easy fix here:)

Widget build(BuildContext context) {
    BuildContext loadingDialogContext;

    return BlocListener<SignUpBloc, SignUpState>(
      listener: (context, state) {
        String message;
        final formStatus = state.formSubmissionStatus;
        if (formStatus is SubmissionFailure) {
          Navigator.of(loadingDialogContext).pop();
          final e = formStatus.exception;
          if (e.code == 'UsernameExistsException' ||
              e.code == 'InvalidParameterException' ||
              e.code == 'InvalidPasswordException' ||
              e.code == 'ResourceNotFoundException') {
            message = e.message;
          } else {
            message = 'An unknown error had occurred. Please try again.';
          }
          toast(
            context: context,
            text: message,
            backgroundColor: kErrorColor,
            textColor: Colors.white,
            iconColor: Colors.white,
          );
        } else if (formStatus is SubmissionInProgress) {
          showDialog(
            context: context,
            builder: (dialogContext) {
              loadingDialogContext = dialogContext;
              return Loader();
            },
            barrierDismissible: false,
          );
        }
      },
      child: Form(
        key: _formKey,
        child: Column(

Answer 1

You can use Scaffold.of :

final scaffoldContext = Scaffold.of(loadingDialogContext).pop();
Navigator.of(loadingDialogContext).pop();
toast(
   context: scaffoldContext,
   text: message,
   backgroundColor: kErrorColor,
   textColor: Colors.white,
   iconColor: Colors.white,
);