The Hero widget in Flutter is used to create hero animations, which animate the transition of a widget between different screens in a visually appealing way. It's commonly used to create smooth transitions for images, text, or other widgets when navigating between routes.
Attributes:
tag (Object):
- A unique tag to identify the hero widget across screens. The same tag should be used for the corresponding hero widget in both the source and destination screens.
child (Widget):
- The widget to be animated between screens. This is typically an image, text, or container widget.
flightShuttleBuilder (Widget Function(BuildContext, Animation<double>, HeroFlightDirection, BuildContext, BuildContext)):
- An optional builder function that creates a widget to be animated between screens. This allows customization of the appearance and behavior of the animated widget during the transition.
placeholderBuilder (Widget Function(BuildContext, Size, Widget)):
- An optional builder function that creates a placeholder widget to be displayed while the hero animation is in progress. This widget is displayed on the source screen until the destination screen is fully loaded.
Example:
import 'package:flutter/material.dart';
class Screen1 extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Screen 1'),
),
body: Center(
child: GestureDetector(
onTap: () {
Navigator.push(
context,
MaterialPageRoute(builder: (context) => Screen2()),
);
},
child: Hero(
tag: 'imageTag',
child: Image.network('https://via.placeholder.com/150'),
),
),
),
);
}
}
class Screen2 extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Screen 2'),
),
body: Center(
child: GestureDetector(
onTap: () {
Navigator.pop(context);
},
child: Hero(
tag: 'imageTag',
child: Image.network('https://via.placeholder.com/300'),
),
),
),
);
}
}
void main() {
runApp(MaterialApp(
home: Screen1(),
));
}
Explanation:
In this example, two screens are created: Screen1 and Screen2.
Screen1 contains an image wrapped with a Hero widget. The tag attribute is set to 'imageTag' to identify the hero animation across screens.
When the image in Screen1 is tapped, it navigates to Screen2 where the same image is displayed with a larger size.
The Hero widget in Screen2 also has the same tag 'imageTag', allowing Flutter to animate the transition between the two screens smoothly.
During the transition, Flutter automatically scales and positions the image to create a visually appealing animation effect.
This example demonstrates how to use the Hero widget to create seamless transitions for widgets between different screens in a Flutter app.