Animating an AlertDialog in Flutter involves using the Flutter animations framework to create custom animations for showing and hiding the dialogue. In this article, we are going to add an animation to an AlertDialog. A sample video is given below to get an idea about what we are going to do in this article.
Basic Syntax of Creating an Animation in Flutter
Create an AnimationController:
final AnimationController _controller = AnimationController(
duration: Duration(seconds: 1), // Set the duration of the animation
vsync: this, // Provide a TickerProvider, often you can use 'this'
);
Define the Animation:
final Animation<double> _animation = Tween<double>(
begin: 0.0, // Starting value of the animation
end: 1.0, // Ending value of the animation
).animate(_controller);
Step By Step Implementation
Step 1: Create a New Project in Android Studio
To set up Flutter Development on Android Studio please refer to Android Studio Setup for Flutter Development, and then create a new project in Android Studio please refer to Creating a Simple Application in Flutter.
Step 2: Import the Package
First of all import material.dart file.
import 'package:flutter/material.dart';
Step 3: Execute the main Method
Here the execution of our app starts.
void main() {
runApp(MyApp());
}
Step 4: Create MyApp Class
In this class we are going to implement the MaterialApp , here we are also set the Theme of our App.
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
// Define the app's theme
theme: ThemeData(
// Set the app's primary theme color
primarySwatch: Colors.green,
),
debugShowCheckedModeBanner: false,
home: OpenDialog(),
);
}
}
Step 5: Create OpenDialog Class
In this class we are going to create a button by clicking the button a animated AlertDialog will opened. Comments are added for better understanding.
class OpenDialog extends StatelessWidget {
// Function to show the animated dialog
void _showAnimatedDialog(BuildContext context) {
showDialog(
context: context,
builder: (BuildContext context) {
return AnimatedAlertDialog();
},
);
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Animated AlertDialog Example'),
),
body: Center(
child: ElevatedButton(
onPressed: () {
_showAnimatedDialog(context);
},
child: Text('Show Animated Dialog'),
),
),
);
}
}
Step 6: Create AnimatedAlertDialog Class
In this class we are going to add animation to an AlertDialog .It define a AnimationController then we use Tween animation for it. Comments are added for better understanding .
class AnimatedAlertDialog extends StatefulWidget {
@override
_AnimatedAlertDialogState createState() => _AnimatedAlertDialogState();
}
class _AnimatedAlertDialogState extends State<AnimatedAlertDialog>
with SingleTickerProviderStateMixin {
late AnimationController _controller;
late Animation<double> _scaleAnimation;
@override
void initState() {
super.initState();
_controller = AnimationController(
vsync: this,
// Adjust the duration as needed
duration: Duration(milliseconds: 800),
);
_scaleAnimation = Tween<double>(begin: 0.0, end: 1.0).animate(_controller);
// Start the animation
// when the dialog is displayed
_controller.forward();
}
@override
void dispose() {
_controller.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return Center(
child: ScaleTransition(
scale: _scaleAnimation,
child: AlertDialog(
title: Text("Animated Alert Dialog"),
content: Text("This is an animated AlertDialog."),
actions: <Widget>[
TextButton(
child: Text("Close"),
onPressed: () {
// Reverse the animation and close the dialog
_controller.reverse();
Navigator.of(context).pop();
},
),
],
),
),
);
}
}
Here is the full Code of main.dart file
import 'package:flutter/material.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
// Define the app's theme
theme: ThemeData(
// Set the app's primary theme color
primarySwatch: Colors.green,
),
debugShowCheckedModeBanner: false,
home: OpenDialog(),
);
}
}
class OpenDialog extends StatelessWidget {
// Function to show the animated dialog
void _showAnimatedDialog(BuildContext context) {
showDialog(
context: context,
builder: (BuildContext context) {
return AnimatedAlertDialog();
},
);
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Animated AlertDialog Example'),
),
body: Center(
child: ElevatedButton(
onPressed: () {
_showAnimatedDialog(context);
},
child: Text('Show Animated Dialog'),
),
),
);
}
}
class AnimatedAlertDialog extends StatefulWidget {
@override
_AnimatedAlertDialogState createState() => _AnimatedAlertDialogState();
}
class _AnimatedAlertDialogState extends State<AnimatedAlertDialog>
with SingleTickerProviderStateMixin {
late AnimationController _controller;
late Animation<double> _scaleAnimation;
@override
void initState() {
super.initState();
_controller = AnimationController(
vsync: this,
duration: Duration(milliseconds: 800), // Adjust the duration as needed
);
_scaleAnimation = Tween<double>(begin: 0.0, end: 1.0).animate(_controller);
// Start the animation when
// the dialog is displayed
_controller.forward();
}
@override
void dispose() {
_controller.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return Center(
child: ScaleTransition(
scale: _scaleAnimation,
child: AlertDialog(
title: Text("Animated Alert Dialog"),
content: Text("This is an animated AlertDialog."),
actions: <Widget>[
TextButton(
child: Text("Close"),
onPressed: () {
// Reverse the animation
// and close the dialog
_controller.reverse();
Navigator.of(context).pop();
},
),
],
),
),
);
}
}