Flutter Cards - 如何在 Flutter 中循环卡片小部件

Question

Main.dart

我想在 flutter.Since 中循环卡片 Angular 2 只是 *ngFor 现在以同样的方式工作正常我如何循环 it.I 找不到和文档颤振网。你会在屏幕截图中找到输出请帮助我了解如何循环卡片或任何其他小部件

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
        home:new MyCard()
    );
  }
}
class MyCard extends StatelessWidget{
  @override
  Widget build(BuildContext context) {
    Widget allcards;
      return new Scaffold(
            appBar: new AppBar(
              title: new Text('My First App'),
              backgroundColor:new Color(0xFF673AB7),
            ),
            body: new Container(
              child: new Column(
                children: <Widget>[
                  new Card(
                    child: new Column(
                      children: <Widget>[
                        new Image.network('https://i.ytimg.com/vi/fq4N0hgOWzU/maxresdefault.jpg'),
                        new Padding(
                          padding: new EdgeInsets.all(7.0),
                          child: new Row(
                            children: <Widget>[
                             new Padding(
                               padding: new EdgeInsets.all(7.0),
                               child: new Icon(Icons.thumb_up),
                             ),
                             new Padding(
                               padding: new EdgeInsets.all(7.0),
                               child: new Text('Like',style: new TextStyle(fontSize: 18.0),),
                             ),
                             new Padding(
                               padding: new EdgeInsets.all(7.0),
                               child: new Icon(Icons.comment),
                             ),
                             new Padding(
                               padding: new EdgeInsets.all(7.0),
                               child: new Text('Comments',style: new TextStyle(fontSize: 18.0)),
                             )

                            ],
                          )
                        )
                      ],
                    ),
                  )
                ],
              ),

            )

        );

    }
}`

这是我的飞镖文件截屏

Answer 1

就像 Angular2 有一个可迭代的循环是使任何循环都有效的原因。

所以我对您的代码进行了一些重构并添加了一个列表，将 Column 更改为 ListView 结果如下：

  class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
        home:new MyCard()
    );
  }
}
class MyCard extends StatelessWidget{
  List cards = new List.generate(20, (i)=>new CustomCard());
  @override
  Widget build(BuildContext context) {
      return new Scaffold(
            appBar: new AppBar(
              title: new Text('My First App'),
              backgroundColor:new Color(0xFF673AB7),
            ),
            body: new Container(
              child: new ListView(
                children: cards,
              )

            )

        );

    }
}

class CustomCard extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
              return  new Card(
                    child: new Column(
                      children: <Widget>[
                        new Image.network('https://i.ytimg.com/vi/fq4N0hgOWzU/maxresdefault.jpg'),
                        new Padding(
                          padding: new EdgeInsets.all(7.0),
                          child: new Row(
                            children: <Widget>[
                             new Padding(
                               padding: new EdgeInsets.all(7.0),
                               child: new Icon(Icons.thumb_up),
                             ),
                             new Padding(
                               padding: new EdgeInsets.all(7.0),
                               child: new Text('Like',style: new TextStyle(fontSize: 18.0),),
                             ),
                             new Padding(
                               padding: new EdgeInsets.all(7.0),
                               child: new Icon(Icons.comment),
                             ),
                             new Padding(
                               padding: new EdgeInsets.all(7.0),
                               child: new Text('Comments',style: new TextStyle(fontSize: 18.0)),
                             )

                            ],
                          )
                        )
                      ],
                    ),
                  );
  }
}

Answer 2

如果有人在上述解决方案中遇到错误，请添加 .toList() 到

List cards = new List.generate(20, (i)=>new CustomCard()).toList();

Answer 3

为了避免这个错误：

This class (or a class which this class inherits from) is marked as '@immutable', but one or more of its instance fields are not final:

就把

final

在这一行：

List cards = new List.generate(20, (i)=>new CustomCard());

留下来：

final List cards = new List.generate(20, (i)=>new CustomCard());

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