animated_widgets
Easily add animations on your screen with AnimatedWidgets.
Optimized for MVVM using Bloc, updating the enabled value of the widget will forward or reverse the animation.
Available widgets : TranslationAnimatedWidget, OpacityAnimatedWidget, RotationAnimatedWidget, ScaleAnimatedWidget, SizeAnimatedWidget
For example : add a TranslationAnimatedWidget on a button, then activate it to display it !
TranslationAnimatedWidget(
enabled: this.displayMyWidget, //update this boolean to forward/reverse the animation
values: [
Offset(0, 200), // disabled value value
Offset(0, 250), //intermediate value
Offset(0, 0) //enabled value
],
child: /* your widget */
),
or using a tween constructor
RotationAnimatedWidget.tween(
enabled: this.displayMyWidget, //update this boolean to forward/reverse the animation
rotationDisabled: Rotation.degrees(z: 0),
rotationEnabled: Rotation.degrees(z: 90),
child: /* your widget */
),
Compose
Don't hesitate to compose them
TranslationAnimatedWidget.tween(
enabled: this.displayMyWidget,
translationDisabled: Offset(0, 200),
translationEnabled: Offset(0, 0),
child:
OpacityAnimatedWidget.tween(
enabled: this.displayMyWidget,
opacityDisabled: 0,
opacityEnabled: 1,
child: /* your widget */
),
),
Opacity
Example using a Stateful Widget
class _StatefulScreenState extends State<StatefulScreen> {
// will determine if the opacity animation is launched
bool _display = false;
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(),
body: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
mainAxisAlignment: MainAxisAlignment.center,
mainAxisSize: MainAxisSize.max,
children: [
//wrap your widget with OpacityAnimatedWidget
OpacityAnimatedWidget.tween(
opacityEnabled: 1, //define start value
opacityDisabled: 0, //and end value
enabled: _display, //bind with the boolean
child: Container(
height: 200,
width: 200,
child: FlutterLogo(
style: FlutterLogoStyle.stacked,
),
),
),
RaisedButton(
color: Colors.blue,
child: Text(
_display ? "hide logo" : "display logo",
style: TextStyle(color: Colors.white),
),
onPressed: () {
setState(() {
//will fire the animation
_display = !_display;
});
},
)
],
),
);
}
}
Translation
Example using bloc pattern
class FirstScreenBloc extends Bloc {
final _viewState = BehaviorSubject<FirstScreenViewState>.seeded(FirstScreenViewState());
Observable<FirstScreenViewState> get viewState => _viewState;
void onClicked() {
_viewState.add(FirstScreenViewState(buttonVisible: true));
}
void onDismissClicked() {
_viewState.add(FirstScreenViewState(buttonVisible: false));
}
@override
void dispose() {
_viewState.close();
}
}
class FirstScreenViewState {
final bool buttonVisible;
const FirstScreenViewState({
this.buttonVisible = false,
});
}
class FirstScreenView extends StatelessWidget {
@override
Widget build(BuildContext context) {
final bloc = BlocProvider.of<FirstScreenBloc>(context);
return StreamBuilder<FirstScreenViewState>(
stream: bloc.viewState,
builder: (context, snapshot) {
final viewState = snapshot.data;
return Stack(
fit: StackFit.expand,
children: [
_buildInputButton(onClicked: () {
bloc.onClicked();
}),
Positioned(
bottom: 20,
left: 20,
right: 20,
child: TranslationAnimatedWidget(
enabled: viewState.buttonVisible, //will forward/reverse the animation
curve: Curves.easeIn,
duration: Duration(seconds: 1),
values: [
Offset(0, 200),
Offset(0, -50),
Offset(0, 0),
],
child: RaisedButton(
onPressed: () {
bloc.onDismissClicked();
},
child: Text("Dismiss"),
),
),
),
],
);
}
);
}
}
Rotation
RotationAnimatedWidget.tween(
enabled: enabled,
rotationDisabled: Rotation.deg(),
rotationEnabled: Rotation.deg(z: 90, x: 80),
child: /* your widget */
),
RotationAnimatedWidget.tween(
enabled: enabled,
rotation: Rotation.deg(),
rotationEnabled: Rotation.deg(z: 90, x: 80),
child: /* your widget */
),
Scale
ScaleAnimatedWidget.tween(
enabled: this._enabled,
duration: Duration(milliseconds: 600),
scaleDisabled: 0.5,
scaleEnabled: 1,
//your widget
child: Container(
height: 200,
width: 200,
child: FlutterLogo(
style: FlutterLogoStyle.stacked,
),
),
),
Size
SizeAnimatedWidget(
enabled: this._enabled,
duration: Duration(milliseconds: 1500),
values: [Size(100, 100), Size(100, 150), Size(200, 150), Size(200, 200)],
curve: Curves.linear,
//your widget
child: Container(
decoration: BoxDecoration(
border: Border.all(color: Colors.blue)
),
child: FlutterLogo(
style: FlutterLogoStyle.stacked,
),
),
),
Shake
ShakeAnimatedWidget(
enabled: this._enabled,
duration: Duration(milliseconds: 1500),
shakeAngle: Rotation.deg(z: 40),
curve: Curves.linear,
child: FlutterLogo(
style: FlutterLogoStyle.stacked,
),
),
Custom Animated
CustomAnimatedWidget(
enabled: this._enabled,
duration: Duration(seconds: 3),
curve: Curves.easeOut,
builder: (context, percent) { //for custom animation, use builders
final int displayedDate = (2018 * percent).floor();
return Text(
"current year : $displayedDate",
style: TextStyle(color: Colors.blue),
);
},
),
Flutter Package
Animated widget is available at https://pub.dev/packages/animated_widgets
dependencies:
animated_widgets:
Getting Started with Flutter
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License
Copyright 2019 florent37, Inc.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.