Question

我试图得到它，以便当按下下一个按钮时它会进入“客户”页面，但是当我点击按钮时没有任何反应。

这是我的代码 package javaapplication1;

import javax.swing.*;
import java.lang.*;
import java.awt.*;
import java.awt.Color;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JFrame;

public class Test extends javax.swing.JPanel implements  ActionListener{

JButton firstButton, lastButton, nextButton, previousButton;
JPanel cardPanel;
String cardNames[] = new String[3];
int cardCounter = 0;

public JPanel createContentPane (){

    JPanel totalGUI = new JPanel();

    JPanel buttonPanel = new JPanel();
    buttonPanel.setLayout(new BoxLayout(buttonPanel, BoxLayout.LINE_AXIS));

    buttonPanel.add(Box.createRigidArea(new Dimension(10,0)));

    previousButton = new JButton("<- Previous");
    previousButton.addActionListener(this);
    buttonPanel.add(previousButton);
    buttonPanel.add(Box.createHorizontalGlue());        

    firstButton = new JButton("First");
    firstButton.addActionListener(this);
    buttonPanel.add(firstButton);
    buttonPanel.add(Box.createHorizontalGlue());

    lastButton =  new JButton("Last");
    lastButton.addActionListener(this);
    buttonPanel.add(lastButton);
    buttonPanel.add(Box.createHorizontalGlue());

    nextButton = new JButton("Next ->");
    nextButton.addActionListener(this);
    buttonPanel.add(nextButton);
    buttonPanel.add(Box.createRigidArea(new Dimension(10,0)));

    JPanel Shop = new JPanel();
    Shop panel1 = new Shop(); 
    Shop.add(panel1);

    JPanel Items = new JPanel();
    Items panel2 = new Items(); 
    Items.add(panel2); 

    JPanel Customers = new JPanel();
    Customers panel3 = new Customers(); 
    Customers.add(panel3); 

    cardPanel = new JPanel(new CardLayout(150, 50));

    cardNames[0] = "Component.CENTER";
    cardNames[1] = "Component.BOTTOM_ALIGNMENT";
    cardNames[2] = "Component.TOP_ALIGNMENT";

    cardPanel.add(Shop, cardNames[0]);
    cardPanel.add(Items, cardNames[1]);
    cardPanel.add(Customers, cardNames[2]);

    JPanel bottomPanel = new JPanel();
    bottomPanel.setLayout(new BorderLayout());

    bottomPanel.add(cardPanel, BorderLayout.CENTER);
    bottomPanel.add(buttonPanel, BorderLayout.PAGE_START);

    totalGUI.add(bottomPanel);
    return totalGUI;
}

public void actionPerformed(ActionEvent e) {


    if(e.getSource() == nextButton)
    {
        CardLayout cl = (CardLayout)(cardPanel.getLayout());

        cl.show(cardPanel, "Customers");
    }
    /*
    if(e.getSource() == firstButton)
    {
        cl.first(cardPanel);
        cardCounter = 0;
    }
    else if(e.getSource() == lastButton)
    {
        cl.last(cardPanel);
        cardCounter = 2;
    }
    else 
    }
    else if(e.getSource() == previousButton)
    {
        cl.previous(cardPanel);
        if(cardCounter > 0)
        {
            cardCounter--;
        }
        else
        {
            cardCounter = 2;
        }*/
    }


protected static void createAndShowGUI() {

    JFrame.setDefaultLookAndFeelDecorated(true);
    JFrame frame = new JFrame("");

    Test demo = new Test();
    frame.setContentPane(demo.createContentPane());

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.setVisible(true);
}

public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            createAndShowGUI();
        }
    });
}

}

为什么会这样？我错过了什么吗？我只是新手使用Cardlayout并且不知道它是如何完全运作的

Answer 1

如有疑问，请查看documentation。

来自CardLayout.addLayoutComponent：

constraints指定的对象必须是字符串。卡片布局将此字符串存储为键值对，可用于随机访问特定卡片。通过调用show方法，应用程序可以显示具有指定名称的组件。

换句话说，传递给CardLayout.show 的String必须与向CardLayout添加组件时作为约束提供的字符串之一相同。

您使用的限制是：

“Component.CENTER”
“Component.BOTTOM_ALIGNMENT”
“Component.TOP_ALIGNMENT”

这些都不符合您传递给CardLayout.show的内容：

cl.show(cardPanel, "Customers");

我正在使用卡片布局在面板之间切换但是当我按下按钮后尝试制作特定面板时没有任何反应

1 个答案: