如何通过此代码中的按钮在HistoryListTile中添加项目？颤振

Question

ListView(
                    shrinkWrap: true,
                    scrollDirection: Axis.vertical,
                    children: <Widget>[
                      HistoryListTile(
                        iconColor: IconColors.transfer,
                        onTap: () {},
                        transactionAmount: "+\$210.00",
                        transactionIcon: IconImgs.transfer,
                        transactionName: "Amazigh Halzoun",
                        transactionType: "TRANSFER",
                      ),
                    ],
                  ),

class HistoryListTile extends StatelessWidget {
  final Color iconColor;
  final String transactionName,
     transactionType,
     transactionAmount,
     transactionIcon;
  final GestureTapCallback onTap;

  const HistoryListTile({
    Key key,
    this.iconColor,
    this.transactionName,
    this.transactionType,
    this.transactionAmount,
    this.transactionIcon,
    this.onTap,
  }) : super(key: key);

 @override
 Widget build(BuildContext context) {
    return Material(
    color: Colors.transparent,
    child: ListTile(
       title: Text(transactionName),
       subtitle: Text(transactionType),
       trailing: Text(transactionAmount),
       leading: CircleAvatar(
          radius: 25,
       child: Image.asset(
          transactionIcon,
          height: 25,
          width: 25,
      ),
      backgroundColor: iconColor,
    ),
    enabled: true,
    onTap: onTap,
     ),
   );
  }
}

很快我们有了一个名为HistoryListTile的Dart文件，该文件定义了列表的参数和设计。

Answer 1

您可以在下面复制粘贴运行完整代码用class History和List<History>控制当使用setState将数据添加到List<History>时，它将显示在ListView

中

代码段

List<History> historyList = [];
...
setState(() {
  historyList.add(History(iconColor: Colors.blue, transactionAmount: "100", transactionIcon: "abc", transactionName: "Hi",transactionType: "def"));

...
class History {
  Color iconColor;
  String transactionName;
  String transactionType;
  String transactionAmount;
  String transactionIcon;

  History({
    this.iconColor,
    this.transactionName,
    this.transactionType,
    this.transactionAmount,
    this.transactionIcon,
  });

工作演示

完整代码

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

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

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;
  final List<String> entries = <String>['A', 'B', 'C'];
  final List<int> colorCodes = <int>[600, 500, 100];
  List<History> historyList = [];

  void _incrementCounter() {
    setState(() {
      historyList.add(History(iconColor: Colors.blue, transactionAmount: "100", transactionIcon: "abc", transactionName: "Hi",transactionType: "def"));
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: ListView.builder(
          padding: const EdgeInsets.all(8),
          itemCount: historyList.length,
          itemBuilder: (BuildContext context, int index) {
            return HistoryListTile(
              iconColor: historyList[index].iconColor,
              onTap: () {},
              transactionAmount: historyList[index].transactionAmount,
              transactionIcon: historyList[index].transactionIcon,
              transactionName: historyList[index].transactionName,
              transactionType: historyList[index].transactionType,
            );

          }
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

class History {
  Color iconColor;
  String transactionName;
  String transactionType;
  String transactionAmount;
  String transactionIcon;

  History({
    this.iconColor,
    this.transactionName,
    this.transactionType,
    this.transactionAmount,
    this.transactionIcon,
  });

  factory History.fromJson(Map<String, dynamic> json) => History(
    iconColor: json["iconColor"],
    transactionName: json["transactionName"],
    transactionType: json["transactionType"],
    transactionAmount: json["transactionAmount"],
    transactionIcon: json["ransactionIcon"],
  );

  Map<String, dynamic> toJson() => {
    "iconColor": iconColor,
    "transactionName": transactionName,
    "transactionType": transactionType,
    "transactionAmount": transactionAmount,
    "ransactionIcon": transactionIcon,
  };
}


class HistoryListTile extends StatelessWidget {
  final Color iconColor;
  final String transactionName,
      transactionType,
      transactionAmount,
      transactionIcon;
  final GestureTapCallback onTap;

  const HistoryListTile({
    Key key,
    this.iconColor,
    this.transactionName,
    this.transactionType,
    this.transactionAmount,
    this.transactionIcon,
    this.onTap,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Material(
      color: Colors.transparent,
      child: ListTile(
        title: Text(transactionName),
        subtitle: Text(transactionType),
        trailing: Text(transactionAmount),
        leading: CircleAvatar(
          radius: 25,
          child: Image.asset(
            transactionIcon,
            height: 25,
            width: 25,
          ),
          backgroundColor: iconColor,
        ),
        enabled: true,
        onTap: onTap,
      ),
    );
  }
}