Building a Flutter AlertDialog in just 15 minutes

The AlertDialog is basically a Popup in Flutter. Whenever you want to create a floating box that is centered on the page, you can simply use an AlertDialog. The implementation of the same is very easy and has been provided in-built with Flutter SDK. So, let's dive in… 👻

What you’ll build?

In this tutorial, you’ll build a mobile app featuring an AlertDialog / Popup in Flutter. The AlertDialog will have the following features:

• Animated loader GIF

• Customized actions buttons

• Curved Edges

This tutorial focuses on adding an AlertDialog to the Flutter app. Non-relevant concepts and code blocks are glossed over and are provided for you to simply copy and paste.

GitHub Profile | shyvum

Setting up Flutter on your machine

The detailed steps to install Flutter on your personal computer & getting started with Flutter is available in the following blog post

AlertDialog constructor

const AlertDialog({
    Key key,
    Widget title,
    EdgeInsetsGeometry titlePadding,
    TextStyle titleTextStyle,
    Widget content,
    EdgeInsetsGeometry contentPadding: const EdgeInsets.fromLTRB(24.0, 20.0, 24.0, 24.0),
    TextStyle contentTextStyle,
    List<Widget> actions,
    Color backgroundColor,
    double elevation,
    String semanticLabel,
    ShapeBorder shape
})

Downloading Assets

Download the GIF by right-clicking, and saving it as listening.gif at /{%PROJECTROOT%}/assets/images/listening.gif

Credits: Bendt on Pinterest

Importing Assets

Import the GIF to your project by adding the file path to your pubspec.yaml file.

...
flutter:
  uses-material-design: true
  assets:
    - assets/images/listening.gif
...

Putting Code in action

Create a file named voicePayDialog.dart in the same directory as of your main.dart file and amend the file with the following code:

import 'package:flutter/material.dart';

class VoicePay extends StatefulWidget {
  @override
  _VoicePayState createState() => _VoicePayState();
}

class _VoicePayState extends State<VoicePay> {

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.all(
          Radius.circular(25),
        ),
      ),
      title: Text(
        'VoicePay',
        textAlign: TextAlign.center,
        style: TextStyle(fontWeight: FontWeight.w700, fontSize: 25.0),
      ),
      content: Column(
        mainAxisSize: MainAxisSize.min,
        mainAxisAlignment: MainAxisAlignment.end,
        crossAxisAlignment: CrossAxisAlignment.center,
        children: <Widget>[
          Image.asset('assets/images/listening.gif'),
          SizedBox(height: 10.0),
          Container(
            alignment: Alignment.center,
            height: 45.0,
            child: Text(
              'Tap on mic to VoicePay',
              style: TextStyle(fontSize: 20.0),
              textAlign: TextAlign.center,
            ),
          ),
          SizedBox(height: 30.0),
          Row(
            mainAxisSize: MainAxisSize.max,
            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
            children: <Widget>[
              IconButton(
                icon: Icon(Icons.keyboard),
                onPressed: () {},
              ),
              IconButton(
                icon: Icon(Icons.mic),
                onPressed: () {},
              ),
              IconButton(
                icon: Icon(Icons.translate),
                onPressed: () {},
              ),
            ],
          ),
        ],
      ),
    );
  }
}

To show the AlertDialog / Popup add the following code to onPressed or onTap parameter of any button in your main.dart file:

onPressed: () {
  showDialog(
    context: context,
    builder: (BuildContext context) {
      return VoicePay();
    },
  );
},

Remember to import voicePayDialog.dart in main.dart

Building & running the application

• Connect your Emulator or physical Android device to test the application.

• Click on Build & Run.

• And Boooom 🧨, your app is ready to launch.

Congratulations!

You have completed this tutorial and have built a Flutter app with an AlertDialog! Also, in the meantime, you integrated GIFs in the App.