How to create a Slide-In and Slide-Out animation in Flutter? - animation

Question

I am trying to create a Slide in and Slide out animation in Flutter. Animation should look like this:
----- Widget slides in ---> Wait for 1 seconds -----Widget slides out of screen -->
I have tried following code but my animation is stuck in a loop.
class _MyStatefulWidgetState extends State<MyStatefulWidget> with SingleTickerProviderStateMixin {
AnimationController _controller;
Animation<Offset> _positionAnimation;
Animation<double> opacityAnimation;
#override
void initState() {
super.initState();
_controller = AnimationController(
duration: const Duration(seconds: 2),
vsync: this,
);
_positionAnimation = Tween<Offset>(
begin: const Offset(-1, 0),
end: const Offset(0, 0.0),
).animate(
CurvedAnimation(
parent: _controller,
curve: Curves.elasticOut),
)..addStatusListener((status) {
print('animation 1 status $status');
if (status == AnimationStatus.completed) {
_controller.reset();
}
if (status == AnimationStatus.dismissed) {
_positionAnimation = Tween<Offset>(
begin: const Offset(0, 0),
end: const Offset(1, 0.0),
).animate(
CurvedAnimation(
parent: _controller,
curve: Curves.elasticIn),
)..addStatusListener((status2) {
print('animation 2 status $status2');
if (status == AnimationStatus.dismissed) {
_controller.reset();
}
});
_controller.forward();
}
});
_controller.forward();
}
#override
void dispose() {
super.dispose();
_controller.dispose();
}
#override
Widget build(BuildContext context) {
return AnimatedBuilder(
builder: _buildAnimation,
animation: _controller,
);
}
Widget _buildAnimation(BuildContext context, Widget child) {
return Opacity(
opacity: 1,
child: SlideTransition(
position: _positionAnimation,
child: Container(
color: Colors.blueAccent,
height: 100,
child: Center(
child: Text(
'Hello, World!',
style: Theme.of(context).textTheme.display1,
),
),
),
),
);
}
With this approach animation is stuck in a loop.
I cannot use staggered animation as I am trying to animate same property. (Or is there a way to use staggered animation on same property?).
Any better way for implementing this?

Answer 1

Taking idea from #pskink code in comments, achieved desired effect with following code using TweenAnimationBuilder:
class _SlideInOutWidgetState extends State<SlideInOutWidget>
with SingleTickerProviderStateMixin {
double startPos = -1.0;
double endPos = 0.0;
Curve curve = Curves.elasticOut;
#override
Widget build(BuildContext context) {
return TweenAnimationBuilder(
tween: Tween<Offset>(begin: Offset(startPos, 0), end: Offset(endPos, 0)),
duration: Duration(seconds: 1),
curve: curve,
builder: (context, offset, child) {
return FractionalTranslation(
translation: offset,
child: Container(
width: double.infinity,
child: Center(
child: child,
),
),
);
},
child: Text('animated text', textScaleFactor: 3.0,),
onEnd: () {
print('onEnd');
Future.delayed(
Duration(milliseconds: 500),
() {
curve = curve == Curves.elasticOut
? Curves.elasticIn
: Curves.elasticOut;
if (startPos == -1) {
setState(() {
startPos = 0.0;
endPos = 1.0;
});
}
},
);
},
);
}
}

Answer 2

Use Marquee plugin for text Animations
Install :
marquee: ^1.3.1
Example :
Marquee(
text: 'There once was a boy who told this story about a boy: "',
)
Fore more info try marquee | flutterpckage