The _dismissingContext is null

[khocef]

Error

E/flutter (14884): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: NoSuchMethodError: The getter 'focusScopeNode' was called on null.
E/flutter (14884): Receiver: null
E/flutter (14884): Tried calling: focusScopeNode

Future<bool> hide() {
    if (_isShowing) {
      try {
        _isShowing = false;
        Navigator.of(_dismissingContext).pop(true);
        if (_showLogs) debugPrint('ProgressDialog dismissed');
        return Future.value(true);
      } catch (_) {
        return Future.value(false);
      }
    } else {
      if (_showLogs) debugPrint('ProgressDialog already dismissed');
      return Future.value(false);
    }
  }

the _dismissingContext context is always null
the _dismissingContext should be initialized