Question

我正在创建测验应用程序，需要根据特定问题的动态选项动态显示mcq选项。

例如：

现在按钮的代码在这里：

    final quizOptions = Container(
      width: MediaQuery.of(context).size.width,
      child: Center(
        child: Column(
          children: <Widget>[
            SimpleRoundButton(
                backgroundColor: Color.fromRGBO(58, 66, 86, 1.0),
                buttonText: Text(questions[questionNum].options[0], 
                    style: TextStyle(
                        color: Colors.white
                    ),
                ),
                textColor: Colors.white,
                onPressed: (){},
            ),
            SimpleRoundButton(
                backgroundColor: Color.fromRGBO(58, 66, 86, 1.0),
                buttonText: Text(questions[questionNum].options[1], 
                    style: TextStyle(
                        color: Colors.white
                    ),
                ),
                textColor: Colors.white,
                onPressed: (){},
            ),
          ],
        ),
      ),
    );

如您所见，我能够做的是“修复”两个按钮。有没有一种方法可以根据特定问题的选项数量来动态添加按钮？

我有一个名为questions的列表，它是一个问题列表（属于一个类）：

class Question {
  String title;
  List options;
  String imagePath;

  Question(
      {this.title, this.options, this.imagePath,});
}


//Example:
Question(
 title: "How fast does the drone go ?",
 options: ['80km/h', '90km/h', '100km/h'],
 imagePath: "assets/images/drones1.jpg",
)

Answer 1

您应该遍历所有选项以创建SimpleRoundButton

...................................
    child: Column(
              children: questions[questionNum].options.map<Widget>(
                (option) =>  SimpleRoundButton(
                    backgroundColor: Color.fromRGBO(58, 66, 86, 1.0),
                    buttonText: Text(option, 
                        style: TextStyle(
                            color: Colors.white
                        ),
                    ),
                    textColor: Colors.white,
                    onPressed: (){},
                ),
           ).toList(),
.........................

Answer 2

我做了一个完整的示例，我使用dynamic widgets在屏幕上显示和隐藏小部件，您也可以在dart fiddle上看到它在线运行。

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  List item = [
    {"title": "Button One", "color": 50},
    {"title": "Button Two", "color": 100},
    {"title": "Button Three", "color": 200},
    {"title": "No show", "color": 0, "hide": '1'},
  ];

  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text("Dynamic Widget - List<Widget>"),backgroundColor: Colors.blue),
        body: Column(
          children: <Widget>[
            Center(child: buttonBar()),
            Text('Click the buttons to hide it'),
          ]
        )
      )
    );
  }

  Widget buttonBar() {
    return Column(
      children: item.where((e) => e['hide'] != '1').map<Widget>((document) {
        return new FlatButton(
          child: new Text(document['title']),
          color: Color.fromARGB(document['color'], 0, 100, 0),
          onPressed: () {
            setState(() {
              print("click on ${document['title']} lets hide it");
              final tile = item.firstWhere((e) => e['title'] == document['title']);
              tile['hide'] = '1';
            });
          },
        );
      }
    ).toList());
  }
}

也许它可以帮助某人。如果对您有用，请告诉我单击向上箭头。谢谢。

https://dartpad.dev/b37b08cc25e0ccdba680090e9ef4b3c1

动态地向窗口中的子列添加窗口小部件

2 个答案: