Flutterで展開可能なListViewを作成する方法
下のスクリーンショットのようなFlutterを使用して展開可能なListViewを作成する方法は？
ExpansionTilesのスクロール可能なリストビューを作成します。これは、展開するとスクロールできないリストビューを表示します。
listView.builder(...)を使用して別のリストビューをネストしたExpansionTilesのリストビューを実装しようとしました。しかし、ExpansionTileを展開すると、リストビューが表示されませんでした...
（スクリーンショットは説明のためのものです）
Flutterで同様の出力を取得する方法はありますか？
EDIT：ソースコード：
import 'package:flutter/material.Dart';
void main() => runApp(
new MaterialApp(
home: new MyApp(),
)
);
var data = {
"01/01/2018": [
["CocaCola", "\$ 5"],
["Dominos Pizza", "\$ 50"],
],
"04/01/2018": [
["Appy Fizz", "\$ 10"],
["Galaxy S9+", "\$ 700"],
["Apple iPhone X", "\$ 999"],
],
};
List<String> dataKeys = data.keys.toList();
String getFullDate(String date) {
List<String> dateSplit = date.split('/');
List<String> months = ["Jan", "Feb", "Mar", "Apr", "May", "June", "July", "Aug", "Sep", "Oct", "Nov", "Dec"];
return "${dateSplit[0]} ${months[int.parse(dateSplit[1]) - 1]} ${dateSplit[2]}";
}
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => new _MyAppState();
}
class _MyAppState extends State<MyApp> {
List<Widget> _buildList(int keyIndex) {
List<Widget> list = [];
for (int i = 0; i < data[dataKeys[keyIndex]].length; i++) {
list.add(
new Row(
children: <Widget>[
new CircleAvatar(
child: new Icon(Icons.verified_user),
radius: 20.0,
),
new Text(data[dataKeys[keyIndex]][i][0])
],
)
);
}
return list;
}
@override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: new Text("Expense Monitor"),
),
body: new Container (
child: new ListView.builder(
itemCount: dataKeys.length,
itemBuilder: (BuildContext context, int keyIndex) {
return new Card(
child: new ExpansionTile(
title: new Text(getFullDate(dataKeys[keyIndex])),
children: <Widget>[
new Column(
children: _buildList(keyIndex)
)
]
),
);
}
)
)
);
}
}
コンソールに表示されるエラー：
I/flutter (12945): ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
I/flutter (12945): The following assertion was thrown during performResize():
I/flutter (12945): Vertical viewport was given unbounded height.
I/flutter (12945): Viewports expand in the scrolling direction to fill their container.In this case, a vertical
I/flutter (12945): viewport was given an unlimited amount of vertical space in which to expand. This situation
I/flutter (12945): typically happens when a scrollable widget is nested inside another scrollable widget.
I/flutter (12945): If this widget is always nested in a scrollable widget there is no need to use a viewport because
I/flutter (12945): there will always be enough vertical space for the children. In this case, consider using a Column
I/flutter (12945): instead. Otherwise, consider using the "shrinkWrap" property (or a ShrinkWrappingViewport) to size
I/flutter (12945): the height of the viewport to the sum of the heights of its children.
I/flutter (12945): When the exception was thrown, this was the stack:
I/flutter (12945): #0 RenderViewport.performResize.<anonymous closure> (package:flutter/src/rendering/viewport.Dart:944:15)
I/flutter (12945): #1 RenderViewport.performResize (package:flutter/src/rendering/viewport.Dart:997:6)
I/flutter (12945): #2 RenderObject.layout (package:flutter/src/rendering/object.Dart:1555:9)
I/flutter (12945): #3 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.Dart:109:13)
......
I/flutter (12945): ════════════════════════════════════════════════════════════════════════════════════════════════════
I/flutter (12945): Another exception was thrown: RenderBox was not laid out: RenderViewport#df29c NEEDS-LAYOUT NEEDS-Paint
これを試して：
import 'package:flutter/material.Dart';
void main() => runApp(new MaterialApp(home: new MyApp(), debugShowCheckedModeBanner: false,),);
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => new _MyAppState();
}
class _MyAppState extends State<MyApp> {
@override
Widget build(BuildContext context) {
return new Scaffold(
body: new ListView.builder(
itemCount: vehicles.length,
itemBuilder: (context, i) {
return new ExpansionTile(
title: new Text(vehicles[i].title, style: new TextStyle(fontSize: 20.0, fontWeight: FontWeight.bold, fontStyle: FontStyle.italic),),
children: <Widget>[
new Column(
children: _buildExpandableContent(vehicles[i]),
),
],
);
},
),
);
}
_buildExpandableContent(Vehicle vehicle) {
List<Widget> columnContent = [];
for (String content in vehicle.contents)
columnContent.add(
new ListTile(
title: new Text(content, style: new TextStyle(fontSize: 18.0),),
leading: new Icon(vehicle.icon),
),
);
return columnContent;
}
}
class Vehicle {
final String title;
List<String> contents = [];
final IconData icon;
Vehicle(this.title, this.contents, this.icon);
}
List<Vehicle> vehicles = [
new Vehicle(
'Bike',
['Vehicle no. 1', 'Vehicle no. 2', 'Vehicle no. 7', 'Vehicle no. 10'],
Icons.motorcycle,
),
new Vehicle(
'Cars',
['Vehicle no. 3', 'Vehicle no. 4', 'Vehicle no. 6'],
Icons.directions_car,
),
];
これを試して！
まず、AnimatedContainerを使用してExpandableContainerを作成します。
次に、ColumnになるExpandableListViewを作成します。 Columnの最初の子は展開するボタンで、2番目はExpandableContainerです。 ExpandableContainerは、その子としてListViewを持ちます。
最後のステップは、LIstViewofExpandableListViewを作成することです。
結果 ：
コード ：
import 'package:flutter/foundation.Dart';
import 'package:flutter/material.Dart';
void main() {
runApp(new MaterialApp(home: new Home()));
}
class Home extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new Scaffold(
backgroundColor: Colors.grey,
appBar: new AppBar(
title: new Text("Expandable List"),
backgroundColor: Colors.redAccent,
),
body: new ListView.builder(
itemBuilder: (BuildContext context, int index) {
return new ExpandableListView(title: "Title $index");
},
itemCount: 5,
),
);
}
}
class ExpandableListView extends StatefulWidget {
final String title;
const ExpandableListView({Key key, this.title}) : super(key: key);
@override
_ExpandableListViewState createState() => new _ExpandableListViewState();
}
class _ExpandableListViewState extends State<ExpandableListView> {
bool expandFlag = false;
@override
Widget build(BuildContext context) {
return new Container(
margin: new EdgeInsets.symmetric(vertical: 1.0),
child: new Column(
children: <Widget>[
new Container(
color: Colors.blue,
padding: new EdgeInsets.symmetric(horizontal: 5.0),
child: new Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: <Widget>[
new IconButton(
icon: new Container(
height: 50.0,
width: 50.0,
decoration: new BoxDecoration(
color: Colors.orange,
shape: BoxShape.circle,
),
child: new Center(
child: new Icon(
expandFlag ? Icons.keyboard_arrow_up : Icons.keyboard_arrow_down,
color: Colors.white,
size: 30.0,
),
),
),
onPressed: () {
setState(() {
expandFlag = !expandFlag;
});
}),
new Text(
widget.title,
style: new TextStyle(fontWeight: FontWeight.bold, color: Colors.white),
)
],
),
),
new ExpandableContainer(
expanded: expandFlag,
child: new ListView.builder(
itemBuilder: (BuildContext context, int index) {
return new Container(
decoration:
new BoxDecoration(border: new Border.all(width: 1.0, color: Colors.grey), color: Colors.black),
child: new ListTile(
title: new Text(
"Cool $index",
style: new TextStyle(fontWeight: FontWeight.bold, color: Colors.white),
),
leading: new Icon(
Icons.local_pizza,
color: Colors.white,
),
),
);
},
itemCount: 15,
))
],
),
);
}
}
class ExpandableContainer extends StatelessWidget {
final bool expanded;
final double collapsedHeight;
final double expandedHeight;
final Widget child;
ExpandableContainer({
@required this.child,
this.collapsedHeight = 0.0,
this.expandedHeight = 300.0,
this.expanded = true,
});
@override
Widget build(BuildContext context) {
double screenWidth = MediaQuery.of(context).size.width;
return new AnimatedContainer(
duration: new Duration(milliseconds: 500),
curve: Curves.easeInOut,
width: screenWidth,
height: expanded ? expandedHeight : collapsedHeight,
child: new Container(
child: child,
decoration: new BoxDecoration(border: new Border.all(width: 1.0, color: Colors.blue)),
),
);
}
}