Question

我正在尝试编写一个包含标题和4个按钮的主页的简短程序，其中3个将离开主屏幕并转到新页面，您可以在其中输入相应的信息。我开始使用拖放编辑器，但通过论坛找到我应该使用cardlayout而不是我已经查看了oracle教程，但我想使用按钮来更换卡而不是组合框。那可能吗。

这里是教程中的代码，我需要更改哪个部分才能使按钮成为更改屏幕的操作按钮。

感谢，

package layout;

/*
 * CardLayoutDemo.java
 *
 */
import java.awt.*;
  import java.awt.event.*;
import javax.swing.*;

public class CardLayoutDemo implements ItemListener {
    JPanel cards; //a panel that uses CardLayout
    final static String BUTTONPANEL = "Card with JButtons";
    final static String TEXTPANEL = "Card with JTextField";

public void addComponentToPane(Container pane) {
    //Put the JComboBox in a JPanel to get a nicer look.
    JPanel comboBoxPane = new JPanel(); //use FlowLayout
    String comboBoxItems[] = { BUTTONPANEL, TEXTPANEL };
    JComboBox cb = new JComboBox(comboBoxItems);
    cb.setEditable(false);
    cb.addItemListener(this);
    comboBoxPane.add(cb);

    //Create the "cards".
    JPanel card1 = new JPanel();
    card1.add(new JButton("Button 1"));
    card1.add(new JButton("Button 2"));
    card1.add(new JButton("Button 3"));

    JPanel card2 = new JPanel();
    card2.add(new JTextField("TextField", 20));

    //Create the panel that contains the "cards".
    cards = new JPanel(new CardLayout());
    cards.add(card1, BUTTONPANEL);
    cards.add(card2, TEXTPANEL);

    pane.add(comboBoxPane, BorderLayout.PAGE_START);
    pane.add(cards, BorderLayout.CENTER);
}

public void itemStateChanged(ItemEvent evt) {
    CardLayout cl = (CardLayout)(cards.getLayout());
    cl.show(cards, (String)evt.getItem());
}

/**
 * Create the GUI and show it.  For thread safety,
 * this method should be invoked from the
 * event dispatch thread.
 */
private static void createAndShowGUI() {
    //Create and set up the window.
    JFrame frame = new JFrame("CardLayoutDemo");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    //Create and set up the content pane.
    CardLayoutDemo demo = new CardLayoutDemo();
    demo.addComponentToPane(frame.getContentPane());

    //Display the window.
    frame.pack();
    frame.setVisible(true);
}

public static void main(String[] args) {
    /* Use an appropriate Look and Feel */
    try {
        //UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
        UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
    } catch (UnsupportedLookAndFeelException ex) {
        ex.printStackTrace();
    } catch (IllegalAccessException ex) {
        ex.printStackTrace();
    } catch (InstantiationException ex) {
        ex.printStackTrace();
    } catch (ClassNotFoundException ex) {
        ex.printStackTrace();
    }
    /* Turn off metal's use of bold fonts */
    UIManager.put("swing.boldMetal", Boolean.FALSE);

    //Schedule a job for the event dispatch thread:
    //creating and showing this application's GUI.
    javax.swing.SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            createAndShowGUI();
        }
    });
}
}

Answer 1

但我想使用按钮更换卡而不是组合框。那可能吗。

本教程使用ItemListener作为组合框。

如果要使用按钮，则可以使用ActionListener。

ActionListener中的代码基本相同。那就是你需要识别你想要改变的卡片。

cl.show(cards, BUTTONPANEL); // for example

虽然按钮可能会显示您要切换到的面板的名称，但您可以执行以下操作：

cl.show(cards, event.getActionCommand());

单击按钮时生成的ActionEvent动作命令包含按钮上显示的文本。

CardLayout带有更换卡片的按钮

1 个答案: