Flutter - Float Action Button - Hiding the visibility of items - dart

Question

I'm trying to control the visibility of the smaller items of the FAB, according to the gif below:
However I am not able to insert the opacity in the items. Anywhere I put some kind of error occurs. I do not know if opacity is the best way to do it.
To hide the items I believe that with animation it is possible to control the time in which they will appear.
Below is what I have achieved so far:
Could you help me solve this problem?
Below is the above gif code:
import 'package:flutter/animation.dart';
import 'package:flutter/material.dart';
void main() {
runApp(new MaterialApp(home: new HomePage()));
}
class HomePage extends StatefulWidget {
#override
HomePageState createState() => new HomePageState();
}
class HomePageState extends State<HomePage> with TickerProviderStateMixin {
int _angle = 90;
bool _isRotated = true;
void _rotate(){
setState((){
if(_isRotated) {
_angle = 45;
_isRotated = false;
} else {
_angle = 90;
_isRotated = true;
}
});
}
#override
Widget build(BuildContext context) {
return new Scaffold(
body: new Stack(
children: <Widget>[
new Positioned(
bottom: 200.0,
right: 24.0,
child: new Container(
child: new Row(
children: <Widget>[
new Container(
margin: new EdgeInsets.only(right: 16.0),
child: new Text(
'foo1',
style: new TextStyle(
fontSize: 13.0,
fontFamily: 'Roboto',
color: new Color(0xFF9E9E9E),
fontWeight: FontWeight.bold,
),
),
),
new Material(
color: new Color(0xFF9E9E9E),
type: MaterialType.circle,
elevation: 6.0,
child: new GestureDetector(
child: new Container(
width: 40.0,
height: 40.0,
child: new InkWell(
onTap: (){},
child: new Center(
child: new Icon(
Icons.add,
color: new Color(0xFFFFFFFF),
),
),
)
),
)
),
],
),
)
),
new Positioned(
bottom: 144.0,
right: 24.0,
child: new Container(
child: new Row(
children: <Widget>[
new Container(
margin: new EdgeInsets.only(right: 16.0),
child: new Text(
'foo2',
style: new TextStyle(
fontSize: 13.0,
fontFamily: 'Roboto',
color: new Color(0xFF9E9E9E),
fontWeight: FontWeight.bold,
),
),
),
new Material(
color: new Color(0xFF00BFA5),
type: MaterialType.circle,
elevation: 6.0,
child: new GestureDetector(
child: new Container(
width: 40.0,
height: 40.0,
child: new InkWell(
onTap: (){},
child: new Center(
child: new Icon(
Icons.add,
color: new Color(0xFFFFFFFF),
),
),
)
),
)
),
],
),
)
),
new Positioned(
bottom: 88.0,
right: 24.0,
child: new Container(
child: new Row(
children: <Widget>[
new Container(
margin: new EdgeInsets.only(right: 16.0),
child: new Text(
'foo3',
style: new TextStyle(
fontSize: 13.0,
fontFamily: 'Roboto',
color: new Color(0xFF9E9E9E),
fontWeight: FontWeight.bold,
),
),
),
new Material(
color: new Color(0xFFE57373),
type: MaterialType.circle,
elevation: 6.0,
child: new GestureDetector(
child: new Container(
width: 40.0,
height: 40.0,
child: new InkWell(
onTap: (){},
child: new Center(
child: new Icon(
Icons.add,
color: new Color(0xFFFFFFFF),
),
),
)
),
)
),
],
),
)
),
new Positioned(
bottom: 16.0,
right: 16.0,
child: new Material(
color: new Color(0xFFE57373),
type: MaterialType.circle,
elevation: 6.0,
child: new GestureDetector(
child: new Container(
width: 56.0,
height: 56.00,
child: new InkWell(
onTap: _rotate,
child: new Center(
child: new RotationTransition(
turns: new AlwaysStoppedAnimation(_angle / 360),
child: new Icon(
Icons.add,
color: new Color(0xFFFFFFFF),
),
)
),
)
),
)
),
),
]
)
);
}
}

Answer 1

I used Opacity but it became redundant after using ScaleTransition. With ScaleTransition it is possible to hide and show widgets.
I used 3 animations to be able to generate the cascade effect.
Below is the code and its result:
import 'package:flutter/animation.dart';
import 'package:flutter/material.dart';
void main() {
runApp(new MaterialApp(home: new HomePage()));
}
class HomePage extends StatefulWidget {
#override
HomePageState createState() => new HomePageState();
}
class HomePageState extends State<HomePage> with TickerProviderStateMixin {
int _angle = 90;
bool _isRotated = true;
AnimationController _controller;
Animation<double> _animation;
Animation<double> _animation2;
Animation<double> _animation3;
#override
void initState() {
_controller = new AnimationController(
vsync: this,
duration: const Duration(milliseconds: 180),
);
_animation = new CurvedAnimation(
parent: _controller,
curve: new Interval(0.0, 1.0, curve: Curves.linear),
);
_animation2 = new CurvedAnimation(
parent: _controller,
curve: new Interval(0.5, 1.0, curve: Curves.linear),
);
_animation3 = new CurvedAnimation(
parent: _controller,
curve: new Interval(0.8, 1.0, curve: Curves.linear),
);
_controller.reverse();
super.initState();
}
void _rotate(){
setState((){
if(_isRotated) {
_angle = 45;
_isRotated = false;
_controller.forward();
} else {
_angle = 90;
_isRotated = true;
_controller.reverse();
}
});
}
#override
Widget build(BuildContext context) {
return new Scaffold(
body: new Stack(
children: <Widget>[
new Positioned(
bottom: 200.0,
right: 24.0,
child: new Container(
child: new Row(
children: <Widget>[
new ScaleTransition(
scale: _animation3,
alignment: FractionalOffset.center,
child: new Container(
margin: new EdgeInsets.only(right: 16.0),
child: new Text(
'foo1',
style: new TextStyle(
fontSize: 13.0,
fontFamily: 'Roboto',
color: new Color(0xFF9E9E9E),
fontWeight: FontWeight.bold,
),
),
),
),
new ScaleTransition(
scale: _animation3,
alignment: FractionalOffset.center,
child: new Material(
color: new Color(0xFF9E9E9E),
type: MaterialType.circle,
elevation: 6.0,
child: new GestureDetector(
child: new Container(
width: 40.0,
height: 40.0,
child: new InkWell(
onTap: (){
if(_angle == 45.0){
print("foo1");
}
},
child: new Center(
child: new Icon(
Icons.add,
color: new Color(0xFFFFFFFF),
),
),
)
),
)
),
),
],
),
)
),
new Positioned(
bottom: 144.0,
right: 24.0,
child: new Container(
child: new Row(
children: <Widget>[
new ScaleTransition(
scale: _animation2,
alignment: FractionalOffset.center,
child: new Container(
margin: new EdgeInsets.only(right: 16.0),
child: new Text(
'foo2',
style: new TextStyle(
fontSize: 13.0,
fontFamily: 'Roboto',
color: new Color(0xFF9E9E9E),
fontWeight: FontWeight.bold,
),
),
),
),
new ScaleTransition(
scale: _animation2,
alignment: FractionalOffset.center,
child: new Material(
color: new Color(0xFF00BFA5),
type: MaterialType.circle,
elevation: 6.0,
child: new GestureDetector(
child: new Container(
width: 40.0,
height: 40.0,
child: new InkWell(
onTap: (){
if(_angle == 45.0){
print("foo2");
}
},
child: new Center(
child: new Icon(
Icons.add,
color: new Color(0xFFFFFFFF),
),
),
)
),
)
),
),
],
),
)
),
new Positioned(
bottom: 88.0,
right: 24.0,
child: new Container(
child: new Row(
children: <Widget>[
new ScaleTransition(
scale: _animation,
alignment: FractionalOffset.center,
child: new Container(
margin: new EdgeInsets.only(right: 16.0),
child: new Text(
'foo3',
style: new TextStyle(
fontSize: 13.0,
fontFamily: 'Roboto',
color: new Color(0xFF9E9E9E),
fontWeight: FontWeight.bold,
),
),
),
),
new ScaleTransition(
scale: _animation,
alignment: FractionalOffset.center,
child: new Material(
color: new Color(0xFFE57373),
type: MaterialType.circle,
elevation: 6.0,
child: new GestureDetector(
child: new Container(
width: 40.0,
height: 40.0,
child: new InkWell(
onTap: (){
if(_angle == 45.0){
print("foo3");
}
},
child: new Center(
child: new Icon(
Icons.add,
color: new Color(0xFFFFFFFF),
),
),
)
),
)
),
),
],
),
)
),
new Positioned(
bottom: 16.0,
right: 16.0,
child: new Material(
color: new Color(0xFFE57373),
type: MaterialType.circle,
elevation: 6.0,
child: new GestureDetector(
child: new Container(
width: 56.0,
height: 56.00,
child: new InkWell(
onTap: _rotate,
child: new Center(
child: new RotationTransition(
turns: new AlwaysStoppedAnimation(_angle / 360),
child: new Icon(
Icons.add,
color: new Color(0xFFFFFFFF),
),
)
),
)
),
)
),
),
]
)
);
}
}

Answer 2

you can see Flutter floating action button with speed dial
or
use https://pub.dartlang.org/packages/flutter_speed_dial
or
flutter Visibility widget
or
https://medium.com/#agungsurya/create-a-simple-animated-floatingactionbutton-in-flutter-2d24f37cfbcc