Flutter using BorderRadiusTween for seperated ClipRRect border radiuses - flutter

Question

in this code we can easily set border radius for all corners, such as
topLeft, topRight, bottomLeft, bottomRight with one line in code for example:
borderRadius: borderRadius.evaluate(CurvedAnimation(parent: _controller, curve: Curves.ease)),
now how can i use that for separated corners? for example:
borderRadius: BorderRadius.only(
topLeft: borderRadius.evaluate(CurvedAnimation(parent: _controller, curve: Curves.ease)),
topRight: borderRadius.evaluate(CurvedAnimation(parent: _controller, curve: Curves.ease)),
),
full source code:
import 'package:flutter/material.dart';
void main() => runApp(MaterialApp(
home: HomePage(),
));
class HomePage extends StatefulWidget {
#override
_HomePageState createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> with SingleTickerProviderStateMixin {
AnimationController _controller;
BorderRadiusTween borderRadius;
Duration _duration = Duration(milliseconds: 500);
Tween<Offset> _tween = Tween(begin: Offset(0, 1), end: Offset(0, 0));
double _height, min = 0.1, initial = 0.3, max = 1;
GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
#override
void initState() {
super.initState();
_controller = AnimationController(vsync: this, duration: _duration);
borderRadius = BorderRadiusTween(
begin: BorderRadius.circular(75.0),
end: BorderRadius.circular(0.0),
);
}
#override
Widget build(BuildContext context) {
return Scaffold(
key: _scaffoldKey,
appBar: AppBar(
title: Text('DraggableScrollableSheet'),
),
floatingActionButton: GestureDetector(
child: FloatingActionButton(
child: AnimatedIcon(icon: AnimatedIcons.menu_close, progress: _controller),
elevation: 5,
backgroundColor: Colors.deepOrange,
foregroundColor: Colors.white,
onPressed: () async {
if (_controller.isDismissed)
_controller.forward();
else if (_controller.isCompleted) _controller.reverse();
},
),
),
body: SizedBox.expand(
child: Stack(
children: <Widget>[
FlutterLogo(size: 500),
SizedBox.expand(
child: SlideTransition(
position: _tween.animate(_controller),
child: DraggableScrollableSheet(
minChildSize: min, // 0.1 times of available height, sheet can't go below this on dragging
maxChildSize: max, // 0.7 times of available height, sheet can't go above this on dragging
initialChildSize: initial, // 0.1 times of available height, sheet start at this size when opened for first time
builder: (BuildContext context, ScrollController controller) {
if (controller.hasClients) {
var dimension = controller.position.viewportDimension;
_height ??= dimension / initial;
if (dimension >= _height * max * 0.9)
_onWidgetDidBuild(() {
_scaffoldKey.currentState.showSnackBar(SnackBar(
content: Text('ON TOP'),
duration: Duration(seconds: 3),
));
});
else if (dimension <= _height * min * 1.1)
_onWidgetDidBuild(() {
_scaffoldKey.currentState.showSnackBar(SnackBar(
content: Text('ON BOTTOM'),
duration: Duration(seconds: 3),
));
});
}
return AnimatedBuilder(
animation: controller,
builder: (context, child) {
return ClipRRect(
borderRadius: borderRadius.evaluate(CurvedAnimation(parent: _controller, curve: Curves.ease)),
child: Container(
color: Colors.blue[800],
child: ListView.builder(
controller: controller,
itemCount: 5,
itemBuilder: (BuildContext context, int index) {
return ListTile(title: Text('Item $index'));
},
),
),
);
},
);
},
),
),
),
],
),
),
);
}
_onWidgetDidBuild(Function callback) {
WidgetsBinding.instance.addPostFrameCallback((_) {
callback();
});
}
}

Answer 1

You don't need to use Tween or any sort of Animation for it.
Check out this example.
class HomePage extends StatefulWidget {
#override
_HomePageState createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> with SingleTickerProviderStateMixin {
AnimationController _controller;
Duration _duration = Duration(milliseconds: 500);
Tween<Offset> _tween = Tween(begin: Offset(0, 1), end: Offset(0, 0));
static double _origRadius = 80;
double _height, min = 0.1, initial = 0.5, max = 1, _radius = _origRadius;
GlobalKey<ScaffoldState> _key = GlobalKey();
#override
void initState() {
super.initState();
_controller = AnimationController(vsync: this, duration: _duration, value: 1);
}
#override
Widget build(BuildContext context) {
return Scaffold(
key: _key,
floatingActionButton: GestureDetector(
child: FloatingActionButton(
child: AnimatedIcon(icon: AnimatedIcons.menu_close, progress: _controller),
elevation: 5,
backgroundColor: Colors.deepOrange,
foregroundColor: Colors.white,
onPressed: () async {
if (_controller.isDismissed)
_controller.forward();
else if (_controller.isCompleted) _controller.reverse();
},
),
),
body: SizedBox.expand(
child: Stack(
children: <Widget>[
FlutterLogo(size: 500),
SizedBox.expand(
child: SlideTransition(
position: _tween.animate(_controller),
child: DraggableScrollableSheet(
minChildSize: min, // 0.1 times of available height, sheet can't go below this on dragging
maxChildSize: max, // 0.7 times of available height, sheet can't go above this on dragging
initialChildSize: initial, // 0.1 times of available height, sheet start at this size when opened for first time
builder: (BuildContext context, ScrollController controller) {
if (controller.hasClients) {
var dimension = controller.position.viewportDimension;
_height ??= dimension / initial;
// this is used for border radius
double initialTop = (_height * max) - _origRadius;
if (dimension > initialTop) {
if (_radius >= 0) {
_radius = _origRadius - (dimension - initialTop);
}
}
}
return ClipRRect(
borderRadius: BorderRadius.only(topLeft: Radius.circular(_radius), topRight: Radius.circular(_radius)),
child: Container(
height: 500.0,
color: Colors.blue[800],
child: ListView.builder(
controller: controller,
itemCount: 15,
itemBuilder: (BuildContext context, int index) {
return ListTile(title: Text('Item $index'));
},
),
),
);
},
),
),
),
],
),
),
);
}
}