java - 用于 KET 测试项目的摇摆导航

Question

我正在为这个 KET 测试项目收集东西。但真正困扰我的一件事是这个页面导航我无法弄清楚如何让它正常工作。我正在尝试使用CardsLayout。但它不能正常工作。我需要帮助如何设置这些窗格。

在底部我需要制作问题编号，首先我想我只会制作 5 个。当按下数字时，它会导航到由该数字标记的页面。下一页和后退按钮导航 +- 一页，结果按钮转到总结测试的最后一页。

Answer 1

看看下面给出的代码。这是一个非常基本的设置和处理程序CardLayout，非常符合您正在寻找的要求。我希望它能帮助您更好地了解CardLayout.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;

public class CardLayoutDemo extends JFrame implements ActionListener
{
    JButton next;
    JButton prev;
    JButton[] buttons ;
    JPanel[]  cards;
    JPanel    centerPanel;//Going to add all cards
    JPanel lowerPanel;
    int currentButton = 0;
    public void prepareAndShowGUI() 
    {
        next      = new JButton("Next>>");
        prev      = new JButton("<<Previous");
        buttons   = new JButton[10];
        String[]  cardsName = {"ONE","TWO","THREE","FOUR","FIVE","SIX","SEVEN","EIGHT","NINE","TEN"};
        cards     = new JPanel[10];
        centerPanel= new JPanel();
        lowerPanel = new JPanel();
        centerPanel.setLayout(new CardLayout());
        for (int i = 0; i < buttons.length ; i++ )
        {
            buttons[i] = new JButton(cardsName[i]);
            buttons[i].addActionListener(this);
            buttons[i].setActionCommand("CARDS"+i);
            lowerPanel.add(buttons[i]);
            cards[i] = new JPanel();
            cards[i].setLayout(new BorderLayout());
            cards[i].setBorder(BorderFactory.createTitledBorder("Card "+(i+1)));
            cards[i].add(new JLabel(cardsName[i], SwingUtilities.CENTER));
            centerPanel.add(cards[i], cardsName[i]);
        }
        getContentPane().add(centerPanel);
        getContentPane().add(lowerPanel,BorderLayout.SOUTH);
        getContentPane().add(next,BorderLayout.EAST);
        getContentPane().add(prev,BorderLayout.WEST);
        next.addActionListener(this);
        prev.addActionListener(this);
        prev.setEnabled(false);
        if (buttons.length == 1)
        {
            next.setEnabled(false);
        }
        setSize(700,400);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);
    }

    public void actionPerformed(ActionEvent evt) 
    {
        JButton clickedButton = (JButton)evt.getSource();
        String command  = clickedButton.getActionCommand();
        if (command.startsWith("CARDS"))
        {
            CardLayout cl = (CardLayout)(centerPanel.getLayout());
            cl.show(centerPanel, clickedButton.getText());
            currentButton = Integer.parseInt(command.substring("CARDS".length()));
            if (currentButton == 0)
            {
                prev.setEnabled(false);
                if (buttons.length > 1)
                {
                    next.setEnabled(true);
                }
            }
            else if (currentButton == buttons.length - 1)
            {
                next.setEnabled(false);
                if (buttons.length > 1)
                {
                    prev.setEnabled(true);
                }
            }
            else
            {
                if (buttons.length > 1)
                {
                    next.setEnabled(true);
                    prev.setEnabled(true);
                }
            }
        }
        else
        {
            if ("Next>>".equals(clickedButton.getText()))
            {
                buttons[++currentButton].doClick();
                if (currentButton == buttons.length - 1)
                {
                    next.setEnabled(false);
                    prev.requestFocus();
                }
                prev.setEnabled(true);
            }
            else if ("<<Previous".equals(clickedButton.getText()))
            {
                buttons[--currentButton].doClick();
                if (currentButton == 0)
                {
                    prev.setEnabled(false);
                    next.requestFocus();
                }
                next.setEnabled(true);
            }
        }

    }     
    public static void main(String[] args) 
    {
        SwingUtilities.invokeLater(new Runnable() 
        {
            public void run() 
            {
                CardLayoutDemo cld = new CardLayoutDemo();
                cld.prepareAndShowGUI();
            }
        });
    }
}

要了解有关如何使用 CardLayout 的更多信息，请观看此官方教程。