Question

如果我有

Class TestModel {
String property1;
String property2;
bool property3;
}

class PageModel {
List<TestModel> information = [all the data for all 3 properties];
}

我想在开始（索引0）的列表信息中添加一个新项（我们称其为newItem），我该怎么做？我知道List.add可用于在List的开头添加项目，但是由于List信息是一个类的列表，因此我不确定在这种情况下我该怎么做。

在将newItem添加到信息中之前，是否需要使newItem成为TestModel类的变量？有没有一种方法可以分别处理每个属性（例如，类似List.add.property1 =“ String”，List.add.property2 =“ String”，List.add.property3 = true）

Answer 1

您可以在下面复制粘贴运行完整代码
您可以使用constructor并直接使用property初始化

代码段

class TestModel {
  String property1;
  String property2;
  bool property3;

  TestModel({this.property1, this.property2, this.property3});
}

class PageModel {
  List<TestModel> information = [
    TestModel(property1: "1", property2: "2", property3: false),
    TestModel(property1: "3", property2: "4", property3: true)
  ];
}

输出

I/flutter ( 7558):  1 2 false
I/flutter ( 7558):  3 4 true

完整代码

import 'package:flutter/material.dart';

class TestModel {
  String property1;
  String property2;
  bool property3;

  TestModel({this.property1, this.property2, this.property3});
}

class PageModel {
  List<TestModel> information = [
    TestModel(property1: "1", property2: "2", property3: false),
    TestModel(property1: "3", property2: "4", property3: true)
  ];
}

void main() {
  PageModel().information.forEach((element) => print(
      " ${element.property1} ${element.property2} ${element.property3.toString()}"));
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}

Flutter-将项目添加到班级列表

1 个答案: