如何使按钮在每次单击按钮时执行不同的“类”答案

【问题标题】：How to make a Button execute different "classes' every button click如何使按钮在每次单击按钮时执行不同的“类”
【发布时间】：2021-08-04 05:34:53
【问题描述】：

我试图让一个浮动操作按钮在每次单击时更改一个文本小部件，我有 3 个类，我希望 ONE 按钮能够在每次单击按钮时调用不同的类，并且当它完成调用第三类时它回到执行第一个类，并不断重复..

我可以使用 onpressed 执行一个类，但我不确定如何在每次点击时执行不同的类..

这是代码

    class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(

        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {

  void classes1(){
    setState(() {
      text = 'This is Text From Class1';
    });
  }

  void classes2(){
    setState(() {
      text = 'This is Text From Class 2';
    });
  }
  void classes3(){
    setState(() {
      text = 'This is Text From Class 3 ';
    });
  }

  String text = '';

  @override
  Widget build(BuildContext context) {

    return Scaffold(
      appBar: AppBar(

        title: Text('AppBar'),
      ),
      body: Center(

        child: Column(

          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              '$text',
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: classes1,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}

【问题讨论】：

标签： android flutter dart flutter-layout

【解决方案1】：

这是您的解决方案，请结帐

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

void main() => runApp(MaterialApp(
    home: 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(

        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
int count = 0;
  void classes1(){
    setState(() {
      text = 'This is Text From Class1';
    });
  }

  void classes2(){
    setState(() {
      text = 'This is Text From Class 2';
    });
  }
  void classes3(){
    setState(() {
      text = 'This is Text From Class 3 ';
    });
  }

  String text = '';

  @override
  Widget build(BuildContext context) {

    return Scaffold(
      appBar: AppBar(

        title: Text('AppBar'),
      ),
      body: Center(

        child: Column(

          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              '$text',
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: (){
          switch (count%3) {
            case 0:
              count++;
              return classes1();
            case 1:
              count++;
              return classes2();
            case 2:
              count++;
              return classes3();
            default:
              return null;
          }

        },
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}

【讨论】：