Flutter: Spinning sync icon in AppBar - flutter

Question

How can I animate an IconButton placed in a AppBar? The sync icon should spinning while a database synchronisation is running.
class _HomePageState extends State<HomePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Dashboard"),
actions: <Widget>[
IconButton(
icon: Icon(Icons.sync), // <-- Icon
onPressed: () {
print("sync");
// start spinning
syncDatabaseFull(); // Returns future and resolves when sync is finish
},
)
],
),
body: Center(
child: RaisedButton(
child: Text('HOME screen'),
onPressed: () {
},
),
),
);
}
}

Answer 1

You can copy paste run full code below
You can extend AnimatedWidget and pass callback
example code below simulate syncDatabaseFull run for 5 seconds
code snippet
class AnimatedSync extends AnimatedWidget {
VoidCallback callback;
AnimatedSync({Key key, Animation<double> animation, this.callback})
: super(key: key, listenable: animation);
Widget build(BuildContext context) {
final Animation<double> animation = listenable;
return Transform.rotate(
angle: animation.value,
child: IconButton(
icon: Icon(Icons.sync), // <-- Icon
onPressed: () => callback()),
);
}
}
actions: <Widget>[
AnimatedSync(
animation: rotateAnimation,
callback: () async{
controller.forward();
await syncDatabaseFull();
controller.stop();
controller.reset();
},
),
],
working demo
full code
import 'package:flutter/material.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
visualDensity: VisualDensity.adaptivePlatformDensity,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class AnimatedSync extends AnimatedWidget {
VoidCallback callback;
AnimatedSync({Key key, Animation<double> animation, this.callback})
: super(key: key, listenable: animation);
Widget build(BuildContext context) {
final Animation<double> animation = listenable;
return Transform.rotate(
angle: animation.value,
child: IconButton(
icon: Icon(Icons.sync), // <-- Icon
onPressed: () => callback()),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage>
with SingleTickerProviderStateMixin {
AnimationController controller;
Animation colorAnimation;
Animation rotateAnimation;
int _counter = 0;
void _incrementCounter() {
setState(() {
_counter++;
});
}
Future<bool> syncDatabaseFull() async{
await Future.delayed(Duration(seconds: 5), () {
});
return Future.value(true);
}
#override
void initState() {
controller =
AnimationController(vsync: this, duration: Duration(seconds: 200));
rotateAnimation = Tween<double>(begin: 0.0, end: 360.0).animate(controller);
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
actions: <Widget>[
AnimatedSync(
animation: rotateAnimation,
callback: () async{
controller.forward();
await syncDatabaseFull();
controller.stop();
controller.reset();
},
),
],
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.headline4,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
),
);
}
}

Answer 2

CustomedSpinningIconButton class
import 'package:flutter/material.dart';
class SpinningIconButton extends AnimatedWidget {
final VoidCallback onPressed;
final IconData iconData;
final AnimationController controller;
SpinningIconButton({Key key, this.controller, this.iconData, this.onPressed})
: super(key: key, listenable: controller);
Widget build(BuildContext context) {
final Animation<double> _animation = CurvedAnimation(
parent: controller,
// Use whatever curve you would like, for more details refer to the Curves class
curve: Curves.linearToEaseOut,
);
return RotationTransition(
turns: _animation,
child: IconButton(
icon: Icon(iconData),
onPressed: onPressed,
),
);
}
}
How to use it:
class _HomePageState extends State<HomePage> with SingleTickerProviderStateMixin {
AnimationController _animationController;
#override
void initState() {
super.initState();
_animationController = AnimationController(
vsync: this,
duration: const Duration(seconds: 1)
);
}
#override
Widget build(BuildContext context) {
...
actions: <Widget>[
SpinningIconButton(
controller: _animationController,
iconData: Icons.sync,
onPressed: () async {
// Play the animation infinitely
_animationController.repeat();
// Sleep 1.5 seconds or await the Async method
print('Something has finished.');
// Complete current cycle of the animation
_animationController.forward(from: _animationController.value);
},
)
],
...
}