所以我刚开始练习CardLayout
,但似乎无法使它起作用。我查看了10多个站点,并且似乎在做与它们相同的事情,但是由于某种原因,我的版本无法正常工作。 next()
方法工作正常,但是调用show()
却无济于事。
private static CardLayout cards;
private static JPanel panel;
private Main() {
super("Card Layout");
setBounds(0, 0, 500, 500);
setDefaultCloseOperation(3);
panel = new JPanel();
add(panel);
cards = new CardLayout();
JPanel p1 = new JPanel();
p1.setBackground(Color.WHITE);
JPanel p2 = new JPanel();
p2.setBackground(Color.BLACK);
JPanel p3 = new JPanel();
p3.setBackground(Color.RED);
JPanel p4 = new JPanel();
p4.setBackground(Color.BLUE);
panel.add("white", p1);
panel.add("black", p2);
panel.add("red", p3);
panel.add("blue", p4);
panel.setLayout(cards);
// cards.next(panel); This works fine for me.
cards.show(panel, "red");
setVisible(true);
}
public static void main(String[] args) {
new Main();
}
您发布的代码有很多问题,但是不起作用的原因仅仅是您的代码顺序错误。在将组件添加到JPanel
之前,需要设置其布局管理器。另外,您正在调用错误的add()
方法。仅在将其包含的JPanel
添加到其父容器之后,才将CardLayout
与JPanel
一起添加到其父容器中。
此外,您发布的代码无法编译,因为类Main
显然扩展了JFrame
,但是您发布的代码中缺少该代码。
这里您的代码已更正。
import java.awt.CardLayout;
import java.awt.Color;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Main extends JFrame {
private static CardLayout cards;
private static JPanel panel;
private Main() {
super("Card Layout");
setBounds(0, 0, 500, 500);
setDefaultCloseOperation(3);
panel = new JPanel();
cards = new CardLayout();
panel.setLayout(cards);
JPanel p1 = new JPanel();
p1.setBackground(Color.WHITE);
JPanel p2 = new JPanel();
p2.setBackground(Color.BLACK);
JPanel p3 = new JPanel();
p3.setBackground(Color.RED);
JPanel p4 = new JPanel();
p4.setBackground(Color.BLUE);
panel.add(p1, "white");
panel.add(p2, "black");
panel.add(p3, "red");
panel.add(p4, "blue");
// cards.next(panel); This works fine for me.
cards.show(panel, "red");
add(panel);
setVisible(true);
}
public static void main(String[] args) {
new Main();
}
}