无法按动按钮才能正常工作

本文介绍了无法按动按钮才能正常工作的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

好吧，我是扑扑/飞镖的新手，所以对我轻松一点。我只是在尝试制作一个非常简单的应用，在该应用中，当您按下按钮时，会有一些文本更新告诉您按下按钮的次数。我不知道为什么这段代码不起作用。出现该按钮，但按此按钮无任何反应。

Ok I'm pretty new to flutter/ dart so go easy on me. I'm just trying to make a very simple app where when you press a button some text updates telling you how many times you have pressed the button. I have no idea why this code doesn't work. The button appears but nothing happens when you press it.

import 'package:flutter/material.dart'; class Homepage extends StatelessWidget { @override Widget build(BuildContext context) { return new Column( children: <Widget>[], ); } } class Buttonz extends StatefulWidget { @override _ButtonBeingPressed createState() => new _ButtonBeingPressed(); } class _ButtonBeingPressed extends State<Buttonz> { int _timesPressed = 0; _buttonWasPressed() { setState(() { _timesPressed++; }); } @override Widget build(BuildContext context) { return new Column(children: <Widget>[ new Center( child: new Row( children: <Widget>[ new Text( 'The button was pressed ' + _timesPressed.toString() + " times"), new RaisedButton( onPressed: _buttonWasPressed(), child: new Row( children: <Widget>[new Text("Press meh")], ), ), ], )) ]); } }

推荐答案

您的问题是您没有将回调传递给 RaisedButton ，而是调用了回调。

Your problem is that you didn't pass a callback to RaisedButton, you invoked your callback.

new RaisedButton( onPressed: _buttonWasPressed(), // invokes function child: new Row(children: <Widget>[new Text("Press meh")]), );

要将回调传递给另一个小部件，您有两种选择：

To pass a callback to another widget you have two choices:

new RaisedButton( onPressed: _buttonWasPressed, // no `()`, child: ... )

通过闭包

Pass a closure

new RaisedButton( onPressed: () { // do something. }, .. )