Encrypted messaging app
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import 'dart:math' as math;
import 'package:flutter/material.dart';
class ExpandableFab extends StatefulWidget {
const ExpandableFab({
Key? key,
this.initialOpen,
required this.distance,
required this.icon,
required this.children,
}) : super(key: key);
final bool? initialOpen;
final double distance;
final Icon icon;
final List<Widget> children;
@override
State<ExpandableFab> createState() => _ExpandableFabState();
}
class _ExpandableFabState extends State<ExpandableFab>
with SingleTickerProviderStateMixin {
late final AnimationController _controller;
late final Animation<double> _expandAnimation;
bool _open = false;
@override
void initState() {
super.initState();
_open = widget.initialOpen ?? false;
_controller = AnimationController(
value: _open ? 1.0 : 0.0,
duration: const Duration(milliseconds: 250),
vsync: this,
);
_expandAnimation = CurvedAnimation(
curve: Curves.fastOutSlowIn,
reverseCurve: Curves.easeOutQuad,
parent: _controller,
);
}
@override
void dispose() {
_controller.dispose();
super.dispose();
}
void _toggle() {
setState(() {
_open = !_open;
if (_open) {
_controller.forward();
} else {
_controller.reverse();
}
});
}
@override
Widget build(BuildContext context) {
return SizedBox.expand(
child: Stack(
alignment: Alignment.bottomRight,
clipBehavior: Clip.none,
children: [
_buildTapToCloseFab(),
..._buildExpandingActionButtons(),
_buildTapToOpenFab(),
],
),
);
}
Widget _buildTapToCloseFab() {
return SizedBox(
width: 56.0,
height: 56.0,
child: Center(
child: Material(
shape: const CircleBorder(),
clipBehavior: Clip.antiAlias,
elevation: 4.0,
child: InkWell(
onTap: _toggle,
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Icon(
Icons.close,
color: Theme.of(context).primaryColor,
),
),
),
),
),
);
}
List<Widget> _buildExpandingActionButtons() {
final children = <Widget>[];
final count = widget.children.length;
final step = 60.0 / (count - 1);
for (var i = 0, angleInDegrees = 15.0;
i < count;
i++, angleInDegrees += step) {
children.add(
_ExpandingActionButton(
directionInDegrees: angleInDegrees,
maxDistance: widget.distance,
progress: _expandAnimation,
child: widget.children[i],
),
);
}
return children;
}
Widget _buildTapToOpenFab() {
return IgnorePointer(
ignoring: _open,
child: AnimatedContainer(
transformAlignment: Alignment.center,
transform: Matrix4.diagonal3Values(
_open ? 0.7 : 1.0,
_open ? 0.7 : 1.0,
1.0,
),
duration: const Duration(milliseconds: 250),
curve: const Interval(0.0, 0.5, curve: Curves.easeOut),
child: AnimatedOpacity(
opacity: _open ? 0.0 : 1.0,
curve: const Interval(0.25, 1.0, curve: Curves.easeInOut),
duration: const Duration(milliseconds: 250),
child: FloatingActionButton(
onPressed: _toggle,
backgroundColor: Theme.of(context).colorScheme.primary,
child: widget.icon,
),
),
),
);
}
}
@immutable
class _ExpandingActionButton extends StatelessWidget {
const _ExpandingActionButton({
required this.directionInDegrees,
required this.maxDistance,
required this.progress,
required this.child,
});
final double directionInDegrees;
final double maxDistance;
final Animation<double> progress;
final Widget child;
@override
Widget build(BuildContext context) {
return AnimatedBuilder(
animation: progress,
builder: (context, child) {
final offset = Offset.fromDirection(
directionInDegrees * (math.pi / 180.0),
progress.value * maxDistance,
);
return Positioned(
right: 4.0 + offset.dx,
bottom: 4.0 + offset.dy,
child: Transform.rotate(
angle: (1.0 - progress.value) * math.pi / 2,
child: child!,
),
);
},
child: FadeTransition(
opacity: progress,
child: child,
),
);
}
}
class ActionButton extends StatelessWidget {
const ActionButton({
Key? key,
this.onPressed,
required this.icon,
}) : super(key: key);
final VoidCallback? onPressed;
final Widget icon;
@override
Widget build(BuildContext context) {
final theme = Theme.of(context);
return Material(
shape: const CircleBorder(),
clipBehavior: Clip.antiAlias,
color: theme.colorScheme.secondary,
elevation: 4.0,
child: IconButton(
onPressed: onPressed,
icon: icon,
color: theme.colorScheme.onSecondary,
),
);
}
}