我在显示带卡布局的下一张卡时遇到了麻烦,我在这里阅读了文档和各种线程。代码是“正常”,但如上所述,不显示下一张卡。这三张卡分别工作,但通过next()方法访问时不可见
以下是代码:
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.JButton;
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class Start {
public static void main(String[] args) {
new Start().createFrame();
}
public void createFrame() {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new Card().createMainGui();
}
});
}
class Card1 extends Card {
public Card1() {
createGui();
}
private void createGui() {
/*
* Create buttons and add them to the Card1 Panel
*/
final JButton button = new JButton("Next");
button.addActionListener(this);
add(button);
}
}
class Card2 extends Card {
public Card2() {
createGui();
}
private void createGui() {
/*
* Create label and add it to the Card2 Panel
*/
JLabel label = new JLabel("Card2");
add(label);
}
}
class Card extends JPanel implements ActionListener {
JFrame frame;
final JPanel cards = new JPanel(new CardLayout(20, 20));
void createMainGui() {
/*
* create main frame
*/
frame = new JFrame("Testframe");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
/*
* add the different cards to the Card Panel (Card Layout)
*/
Card1 card1 = new Card1();
cards.add(card1, "card1");
Card2 card2 = new Card2();
cards.add(card2, "card2");
// Card3 card3 = new Card3();
// cards.add(card3, "card3");
/*
* add the Card panel to the frame, pack it and make it visible
*/
frame.add(cards, BorderLayout.CENTER);
frame.pack();
frame.setVisible(true);
}
@Override
public void actionPerformed(ActionEvent e) {
CardLayout cl = (CardLayout) cards.getLayout();
cl.next(cards);
}
}
}
答案 0 :(得分:1)
我的代码中的错误是,我从Card1
类扩展了Card2
和Card
类。因此,他们也继承了创建变量cards
的方法。在EventListener
中,引用了错误的cards
变量(在类Card1
中创建的变量),因此EventListener
不起作用。
解决方案:移除extend
和Card1
中的Card2
并将EventListener
移至类Cards
的内部类
private class NewBlaBlaListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
//do your stuff here
}
}
并将ActionListener
中的Cards
添加到Card1
card1.addNewBlaBlaListener(new NewBlaBlaListener());
干杯