Working with AlertDialog in Flutter

AlertDialog is a built-in widget in Flutter that has an optional title, optional content, and an optional list of actions.

In general, the AlertDialog widget is used with the showDialog() function (a built-in function of Flutter) like so:

showDialog(
        context: context,
        builder: (_) => AlertDialog(/*...*/)
);

To close that dialog, just use:

Navigator.of(context).pop()

Example

The tiny app we are going to build contains a button in the center of the screen. When the button gets pressed, a dialog with a Close button will show up. You can make the dialog go away by hitting the Close button or tapping outside the dialog.

Preview:

This is the function that is called when the button is pressed:

void _show(BuildContext ctx) {
    showDialog(
        context: ctx,
        builder: (_) => AlertDialog(
              title: const Text('I am an alert dialog'),
              content: const Text('You are so handsome!'),
              actions: [
                TextButton(
                    onPressed: () => Navigator.of(ctx).pop(),
                    child: const Text('Close '))
              ],
            ));
}

The full code in main.dart:

// kindacode.com
// main.dart
import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      // Hide the debug banner
      debugShowCheckedModeBanner: false,
      title: 'Kindacode.com',
      home: HomePage(),
    );
  }
}

class HomePage extends StatefulWidget {
  const HomePage({Key? key}) : super(key: key);

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  // Show the alert dialog
  // The context is the context of the widget that calls this method
  void _show(BuildContext ctx) {
    showDialog(
        context: ctx,
        builder: (_) => AlertDialog(
              title: const Text('I am an alert dialog'),
              content: const Text('You are so handsome!'),
              actions: [
                TextButton(
                    onPressed: () => Navigator.of(ctx).pop(),
                    child: const Text('Close '))
              ],
            ));
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Kindacode.com'),
      ),
      body: Center(
        // This button will show the alert dialog
        child: ElevatedButton(
          child: const Text('Show the aert dialog'),
          onPressed: () => _show(context),
        ),
      ),
    );
  }
}

That’s it. Further reading:

• How to Make a Confirm Dialog in Flutter
• Flutter Cupertino Button – Tutorial and Examples
• Flutter: SliverGrid example
• Flutter: Creating OTP/PIN Input Fields (2 approaches)
• Write a simple BMI Calculator with Flutter (Null Safety)
• Flutter StreamBuilder examples (null safety)

You can also take a tour around our Flutter topic page and Dart topic page to see the latest tutorials and examples.