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Added preliminary code for the carousel widget

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This commit is contained in:
Mariano Uvalle 2019-04-13 21:26:19 -05:00
parent 40e91caf47
commit cce2b668c0
1 changed files with 123 additions and 0 deletions
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lib/src/widgets/carousel.dart Normal file
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import 'package:flutter/material.dart';
class Carousel extends StatefulWidget {
_CarouselState createState() => _CarouselState();
}
class _CarouselState extends State<Carousel> {
double _offset;
static const kDefaultItemSize = 100.0;
static const kDefaultSeparatorSize = 10.0;
ScrollController _controller = ScrollController();
int _currentWidgetIndex = 0;
initState() {
super.initState();
_controller.addListener(displayCurrentWidget);
}
void scrollToItem(int itemIndex) {
final position = (kDefaultSeparatorSize + kDefaultItemSize) * itemIndex;
_controller.animateTo(
position,
curve: Curves.easeInOut,
duration: Duration(milliseconds: 300),
);
}
void displayCurrentWidget() {
final currentPosition = _controller.offset;
int newWidgetIndex;
if (currentPosition < 0) {
newWidgetIndex = 0;
} else {
final distanceFromLower =
currentPosition % (kDefaultSeparatorSize + kDefaultItemSize);
if (distanceFromLower <= (kDefaultSeparatorSize + kDefaultItemSize) / 2) {
newWidgetIndex =
currentPosition ~/ (kDefaultSeparatorSize + kDefaultItemSize);
} else {
newWidgetIndex =
currentPosition ~/ (kDefaultSeparatorSize + kDefaultItemSize) + 1;
}
}
if (newWidgetIndex != _currentWidgetIndex) {
_currentWidgetIndex = newWidgetIndex;
print(_currentWidgetIndex);
}
}
Widget build(BuildContext context) {
final width = MediaQuery.of(context).size.width;
_offset = width / 2 - 50;
return Container(
height: 100.0,
child: ListView(
controller: _controller,
scrollDirection: Axis.horizontal,
children: <Widget>[
SizedBox(width: _offset),
GestureDetector(
onTap: () => scrollToItem(0),
behavior: HitTestBehavior.opaque,
child: Container(
color: Colors.white,
width: kDefaultItemSize,
child: Center(
child: Text('0'),
),
),
),
SizedBox(width: kDefaultSeparatorSize),
GestureDetector(
onTap: () => scrollToItem(1),
behavior: HitTestBehavior.opaque,
child: Container(
color: Colors.white,
width: kDefaultItemSize,
child: Center(
child: Text('1'),
),
),
),
SizedBox(width: kDefaultSeparatorSize),
GestureDetector(
onTap: () => scrollToItem(2),
behavior: HitTestBehavior.opaque,
child: Container(
color: Colors.white,
width: kDefaultItemSize,
child: Center(
child: Text('2'),
),
),
),
SizedBox(width: kDefaultSeparatorSize),
GestureDetector(
onTap: () => scrollToItem(3),
behavior: HitTestBehavior.opaque,
child: Container(
color: Colors.white,
width: kDefaultItemSize,
child: Center(
child: Text('3'),
),
),
),
SizedBox(width: kDefaultSeparatorSize),
GestureDetector(
onTap: () => scrollToItem(4),
behavior: HitTestBehavior.opaque,
child: Container(
color: Colors.white,
width: kDefaultItemSize,
child: Center(
child: Text('4'),
),
),
),
SizedBox(width: _offset),
],
),
);
}
}