GUI关闭问题? [英] GUI close issue?

问题描述

我有一个程序，它显示两个按钮并在翻转时更改其中一个按钮的图像.我的

I have a program which displays two buttons and changes the image of one of the buttons on roll over. I am getting an error on my

press.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

部分，它看起来像这样: ButtonClass 类型的方法 setDefaultCloseOperation(int) 是未定义的.即使在关闭时退出注释还有更多错误，请帮助.

part, And it looks like this: The method setDefaultCloseOperation(int) is undefined for the type ButtonClass. Even with the exit on close commented out there are more errors, please help.

主类(有错误):

package Buttons;
import javax.swing.JFrame;

public class Main_buttons{

public static void main(String[] args) {

    ButtonClass press = new ButtonClass();
    press.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    press.setSize(300,200);
    press.setVisible(true);
    }
}

ButtonClass 类:

ButtonClass class:

package Buttons;

import java.awt.FlowLayout; //layout proper
import java.awt.event.ActionListener; //Waits for users action
import java.awt.event.ActionEvent; //Users action
import javax.swing.JFrame; //Window
import javax.swing.JButton; //BUTTON!!!
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JOptionPane; //Standard dialogue box

public class ButtonClass extends JButton {

private JButton regular;
private JButton custom;

public ButtonClass() { // Constructor
    super("The title"); // Title
    setLayout(new FlowLayout()); // Default layout

    regular = new JButton("Regular Button");
    add(regular);

    Icon b = new ImageIcon(getClass().getResource("img.png"));
    Icon x = new ImageIcon(getClass().getResource("swag.png"));
    custom = new JButton("Custom", b);
    custom.setRolloverIcon(x); //When you roll over the button that says custom the image will change from b to x
    add(custom);

    Handlerclass handler = new Handlerclass();
    regular.addActionListener(handler);
    custom.addActionListener(handler);

}

 private class Handlerclass implements ActionListener { // This class is inside the other  class


    public void actionPerformed(ActionEvent eventvar) { // This will happen
                                                        // when button is
                                                        // clicked
        JOptionPane.showMessageDialog(null, String.format("%s", eventvar.getActionCommand()));//Opens a new window with the name of the button
    }
}



}

我到处搜索这个问题，但一无所获.请告诉我如何解决有关退出窗口的问题.谢谢！

I have searched everywhere for this problem and found nothing. Please tell me how to resolve this issue about exiting my window. Thanks!

推荐答案

当您创建一个扩展 JButton 的类并在其上调用 setVisible(true) 作为如果它是一个顶级窗口，如 JFrame 或 JDialog，那没有意义.由于它不是顶级窗口，因此没有默认关闭操作或了解其含义也很有意义.

You're a little confused as you're creating a class that extends JButton, and calling setVisible(true) on it as if it were a top-level window such as a JFrame or JDialog, and that doesn't make sense. Since it isn't a top-level window it also makes sense to not have a default close operation or understand what that means.

我建议您仅在顶级窗口(例如 JFrame 或 JDialog 等)上调用此方法.作为附带建议，我通常避免使用 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);，而是更频繁地使用 setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);，这给了它更多的灵活性.

I suggest that you call this method only on top-level windows such as on a JFrame or JDialog and the like. As a side recommendation, I usually avoid setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); and instead more often do setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); which gives it a little more flexibility.

实际上，只需将您的类更改为扩展 JFrame 而不是扩展 JButton.

actually, just change your class to extends JFrame not extends JButton.

确保资源的图片路径正确.例如:

Make sure your image path to your resources is correct. For example:

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