import 'package:flutter/material.dart'; mixin ShowErrorDialog on State { void showErrorDialog(BuildContext context, String text) { // Create AlertDialog AlertDialog dialog = AlertDialog( title: Text("Error"), content: Text(text), actions: [ ElevatedButton( child: Text("OK"), style: ElevatedButton.styleFrom( padding: EdgeInsets.symmetric(horizontal: 50, vertical: 20), textStyle: TextStyle(fontSize: 15, fontWeight: FontWeight.normal)), onPressed: () { Navigator.of(context).pop("Yes, Of course!"); // Return value }), ], ); // Call showDialog function to show dialog. Future futureValue = showDialog( context: context, builder: (BuildContext context) { return dialog; }); } }