Flutter：listview 和 expandTile 的类

问题描述

我正在遵循 How to create Expandable ListView in Flutter 的建议解决方案，如下所示：

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,];

如何修改“class Vehicle”以添加年份和颜色等信息？ 年份和颜色信息将使用“onTap”在新屏幕中显示/使用

谢谢

解决方法

要为类添加年份和颜色，请修改您的车辆类，如下所示，

class Vehicle {
  final String title;
  List<String> contents = [];
  final IconData icon;
  int year;
  Color vehicleColor;

  Vehicle({this.title,this.contents,this.icon,this.year,this.vehicleColor});
}

最好使您的构造函数参数 Named Parameters 以避免以后混淆，或者您也可以使它们Positional parameters。

有关命名参数和可选参数的更多信息检查 this。

现在您可以轻松地将数据添加到您的列表中

List<Vehicle> vehicles = [
  new Vehicle(
    title: 'Bike',contents: [
      'Vehicle no. 1','Vehicle no. 2','Vehicle no. 7','Vehicle no. 10'
    ],icon: Icons.motorcycle,year: 2018,vehicleColor: Colors.blue,),new Vehicle(
    title: 'Bike',year: 2019,vehicleColor: Colors.red,];

当你想将数据添加到列表中时，只需调用这行代码， 在 onTap 方法中

  vehicles.add(Vehicle(
    title: 'Bike',));