Java CardLayout 主菜单问题 [英] Java CardLayout Main Menu Problem
问题描述
好的，我正在用 Java 开发这款名为 8 位嵌合体的游戏.我现在在主菜单上工作，但是当我使用卡片布局时，由于某种原因，窗口不会打开.这是一些代码.
Ok so im working on this game in java called 8 bit chimera. Im working on the main menu right now but when im using the card layout the window wont open for some reason. Here is some code.
import javax.swing.*;
import java.awt.*;
public class MainScreen extends JFrame{
String Title = "MainMenu";
MainMenuComp MMC = new MainMenuComp();
BreedingGround BGR = new BreedingGround();
public MainScreen() {
setTitle("8-bit Chimera "+Title);
setSize(800,600);
setResizable(false);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
add(MMC);
add(BGR);
}
public static void main(String[] args){
new MainScreen();
}
}
那是主窗口
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class MainMenuComp extends JPanel implements ActionListener{
BreedingGround BGR = new BreedingGround();
ImageData ID = new ImageData();
Image TitleBg;
Image Title;
CardLayout CL;
JButton Play;
public MainMenuComp() {
setLayout(new GridBagLayout());
GridBagConstraints GBC = new GridBagConstraints();
ImageIcon TitleData = new ImageIcon(ID.TitleSource);
ImageIcon TitleBackGroundData = new ImageIcon(ID.TitleBackGroundSource);
ImageIcon PlayData = new ImageIcon(ID.PlaySource);
TitleBg = TitleBackGroundData.getImage();
Title = TitleData.getImage();
Play = new JButton();
Play.setIcon(PlayData);
add(Play,GBC);
add(BGR,"Breed");
}
public void actionPerformed(ActionEvent AE){
if(AE.getSource() == Play){
CL.show(this, "Breed");
}
}
public void paintComponent(Graphics g){
g.drawImage(TitleBg,0,0,800,600,this);
g.drawImage(Title,250,80,280,140,this);
}
}
这是卡片布局
import javax.swing.*;
import java.awt.*;
public class BreedingGround extends JPanel{
ImageData ID = new ImageData();
Image Swamp;
CardLayout CL;
public BreedingGround(){
setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
ImageIcon SwampData = new ImageIcon(ID.SwampSource);
Swamp = SwampData.getImage();
}
public void paintComponent(Graphics g){
g.drawImage(Swamp,0,0,800,600,this);
}
}
这就是我希望 CardLayout 打开的内容.问题是，当我尝试运行它时，窗口不会运行，并且一直显示在编译器中.
and that was what i wanted the CardLayout to open. The problem is that when i try to run it the window wont run and this keeps showing in the compiler.
------------配置:8-bit Chimera - JDK version 1.6.0_26 ---------------------
--------------------Configuration: 8-bit Chimera - JDK version 1.6.0_26 - --------------------
Exception in thread "main" java.lang.IllegalArgumentException: cannot add to layout: constraints must be a GridBagConstraint
at java.awt.GridBagLayout.addLayoutComponent(GridBagLayout.java:685)
at java.awt.Container.addImpl(Container.java:1074)
at java.awt.Container.add(Container.java:927)
at MainMenuComp.<init>(MainMenuComp.java:26)
at MainScreen.<init>(MainScreen.java:7)
at MainScreen.main(MainScreen.java:23)
流程已完成.
我真正想知道的是这在说什么.
All i really want to know is what this is saying.
推荐答案
我没看到你在哪里设置了一个容器的布局为 CardLayout，如果你不设置布局为这个，你可以't 神奇地使用它.如果您尚未阅读CardLayout 教程，请考虑这样做，因为它在那里解释过.
I don't see where you ever set the layout of a container to be CardLayout, and if you don't set the layout to this, you can't magically use it. If you haven't yet gone through the CardLayout tutorial, consider doing so as it's all explained there.
编辑 1
来自 Alexander Kim 的评论:
Edit 1
Comment from Alexander Kim:
当我添加 cardbagLayout 时，它不会加载图像并且按钮大小填满整个屏幕.我也拿走了格子
when i added the cardbagLayout it wont load the image and the button size filled the whole screen. I also took away the grids
您需要嵌套 JPanel 以嵌套布局.使用单个 JPanel 作为 CardLayout 容器，其唯一功能是显示其他 JPanel(卡片").这些其他 JPanel 将使用任何必要的布局来正确显示它们所持有的组件，例如 JButton 或网格"(无论它们是什么).甚至这些 JPanel 也可能包含使用其他布局的其他 JPanel.
You need to nest your JPanels in order to nest layouts. Use a single JPanel as the CardLayout container whose single function it is is to display other JPanels (the "cards"). These other JPanels will use whatever layouts that are necessary to properly display the components that they hold such as your JButton or "grids" (whatever they are). And even these JPanels may hold other JPanels that use other layouts.
再次，请阅读布局教程，因为它在那里描述得很好.你不会后悔这样做.
Again, please read the layout tutorials as it's all described well there. You will not regret doing this.
编辑 2
这是一个使用 CardLayout 的非常简单的示例.CardLayout 使用 JPanel 显示的组件(称为 cardContainer)根据在组合框中选择的项目而变化.
Edit 2
Here's a very simple example that uses a CardLayout. The component displayed by the CardLayout using JPanel (called the cardContainer) is changed depending on which item is selected in a combobox.
这是 CardLayout 和使用它的 JPanel:
Here's the CardLayout and the JPanel that uses it:
私有 CardLayout cardLayout = new CardLayout();
private CardLayout cardLayout = new CardLayout();
// *** JPanel to hold the "cards" and to use the CardLayout:
private JPanel cardContainer = new JPanel(cardLayout);
这里是我如何使用 JPanel 向 cardlayout 添加组件:
And here's how I add a component to the cardlayout-using JPanel:
JPanel redPanel = new JPanel();
//...
String red = "Red Panel";
cardContainer.add(redPanel, red); // add the JPanel to the container with the String
我还将字符串添加到 JComboBox，以便我稍后可以使用此组合框告诉 CardLayout 如果用户在同一个 JComboBox 中选择项目Red"来显示此 JPanel(redPanel):
I also add the String to a JComboBox so I can use this combo box later to tell the CardLayout to display this JPanel (redPanel) if the user selects the item "Red" in this same JComboBox:
cardCombo.addItem(red); // also add the String to the JComboBox
这是 JComboBox 中的 ActionListener，它允许我使用 JPanel 更改卡片布局中显示的项目:
Here's the ActionListener in the JComboBox that lets me change the item displayed in the cardlayout using JPanel:
cardCombo.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String item = cardCombo.getSelectedItem().toString();
// *** if combo box changes it tells the CardLayout to
// *** swap views based on the item selected in the combo box:
cardLayout.show(cardContainer, item);
}
});
这里是整个shebang:
And here's the whole shebang:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class SimpleCardLayoutDemo {
private CardLayout cardLayout = new CardLayout();
// *** JPanel to hold the "cards" and to use the CardLayout:
private JPanel cardContainer = new JPanel(cardLayout);
private JComboBox cardCombo = new JComboBox();
private JPanel comboPanel = new JPanel();;
public SimpleCardLayoutDemo() {
JPanel greenPanel = new JPanel(new BorderLayout());
greenPanel.setBackground(Color.green);
greenPanel.add(new JScrollPane(new JTextArea(10, 25)), BorderLayout.CENTER);
greenPanel.setBorder(BorderFactory.createEmptyBorder(15, 15, 15, 15));
greenPanel.add(new JButton("Bottom Button"), BorderLayout.PAGE_END);
String green = "Green Panel";
cardContainer.add(greenPanel, green);
cardCombo.addItem(green);
JPanel redPanel = new JPanel();
redPanel.setBackground(Color.red);
redPanel.add(new JButton("Foo"));
redPanel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
String red = "Red Panel";
cardContainer.add(redPanel, red);
cardCombo.addItem(red);
JPanel bluePanel = new JPanel();
bluePanel.setBackground(Color.blue);
JLabel label = new JLabel("Blue Panel", SwingConstants.CENTER);
label.setForeground(Color.white);
label.setFont(label.getFont().deriveFont(Font.BOLD, 32f));
bluePanel.add(label);
String blue = "Blue Panel";
cardContainer.add(bluePanel, blue);
cardCombo.addItem(blue);
comboPanel.add(cardCombo);
cardCombo.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String item = cardCombo.getSelectedItem().toString();
// *** if combo box changes it tells the CardLayout to
// *** swap views based on the item selected in the combo box:
cardLayout.show(cardContainer, item);
}
});
}
public JPanel getCardContainerPanel() {
return cardContainer;
}
public Component getComboPanel() {
return comboPanel ;
}
private static void createAndShowUI() {
SimpleCardLayoutDemo simplecardDemo = new SimpleCardLayoutDemo();
JFrame frame = new JFrame("Simple CardLayout Demo");
frame.getContentPane().add(simplecardDemo.getCardContainerPanel(), BorderLayout.CENTER);
frame.getContentPane().add(simplecardDemo.getComboPanel(), BorderLayout.PAGE_END);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
// to run Swing in a thread-safe way
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}
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