卡片布局 - java GUI

Question

Java中的CardLayout((是如何工作的？我使用互联网，似乎无法让CardLayout工作。这是我到目前为止的代码，它不起作用：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class GameManager
{
JFrame frame;
JPanel cards,title;
public GameManager()
{
cards = new JPanel(new CardLayout());
title = new JPanel();
cards.add(title,"title");
CardLayout cl = (CardLayout)(cards.getLayout());
cl.show(cards, "title");
}
public static void main(String [] args)
{
GameManager gm = new GameManager();
gm.run();
}
public void run()
{
frame = new JFrame("Greek Olympics");
frame.setSize(1000,1000);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(cards);
frame.setVisible(true);
CardLayout cl = (CardLayout)(cards.getLayout());
cl.show(cards, "title");
}
public class title extends JPanel
{
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.fillRect(100,100,100,100);
}
}
}

我应该怎么做才能让面板标题显示我绘制的矩形，因为它没有显示我到目前为止拥有的代码。

Answer 1

初始化局部变量时title您正在创建JPanel的实例，而不是您定义的title类。

为了清楚起见，并遵守 Java 命名约定，您应该将类名大写 (Title(。然后，您需要更改为要Title的title变量的类型。

这是更新的代码，我突出显示了更改的地方。

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class GameManager {
JFrame frame;
JPanel cards; // <-----
Title title; // <-----
public GameManager(){
cards = new JPanel(new CardLayout());
title = new Title(); // <-----
cards.add(title,"title");
CardLayout cl = (CardLayout)(cards.getLayout());
cl.show(cards, "title");
}
public static void main(String [] args){
GameManager gm = new GameManager();
gm.run();
}
public void run(){
frame = new JFrame("Greek Olympics");
frame.setSize(1000,1000);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(cards);
frame.setVisible(true);
CardLayout cl = (CardLayout)(cards.getLayout());
cl.show(cards, "title");
}
public class Title extends JPanel { // <-----
public void paintComponent(Graphics g){
super.paintComponent(g);
g.fillRect(100,100,100,100);
}
}
}