我想为我的组合框中的每个选择更改CardLayout(包含标签)中的卡片。因此,当我在组合框中选择Item2时,它应该显示第二张卡片,但它返回错误。
在方法initComponents()]内部>我成功地使用cardLayout.show(imagePanel,“ 1”);显示了第一张卡片,但是当我尝试在private void comboMenuActionPerformed() ,则返回错误“ IllegalArgumentException:CardLayout的父级错误”。为什么会这样?
public class MyFrame extends JFrame {
public MyFrame() {
initComponents();
}
private void initComponents() {
cardLayout = new java.awt.CardLayout();
mainPanel = new javax.swing.JPanel();
centerPanel = new javax.swing.JPanel();
imagePanel = new javax.swing.JPanel(cardLayout);
comboMenu = new javax.swing.JComboBox<>();
JLabel firstPicture = new JLabel("");
JLabel secondPicture = new JLabel("");
...
firstPicture.setIcon(...);
secondPicture.setIcon(...);
imagePanel.add(firstPicture, "1");
imagePanel.add(secondPicture, "2");
String[] menu = {"Item1", "Item2", "Item3"};
cardLayout.show(imagePanel, "1"); //this works fine
imagePanel.setLayout(new java.awt.CardLayout());
centerPanel.add(imagePanel);
comboMenu.setModel(new javax.swing.DefaultComboBoxModel<>(menu));
mainPanel.add(centerPanel);
}
private void comboMenuActionPerformed(java.awt.event.ActionEvent evt) {
if(comboMenu.getSelectedItem().toString().equals("Item2")) {
cardLayout.show(imagePanel, "2"); //WHY THIS DOESN'T WORK
}
}
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new MyFrame().setVisible(true);
}
});
}
private javax.swing.JComboBox<String> comboMenu;
private javax.swing.JPanel centerPanel;
private javax.swing.JPanel imagePanel;
private javax.swing.JPanel mainPanel;
private java.awt.CardLayout cardLayout;
}
我想为我的组合框中的每个选择更改CardLayout(包含标签)中的卡片。因此,当我在组合框中选择Item2时,它应该显示第二张卡片,但它返回错误。 ...
imagePanel = new javax.swing.JPanel(cardLayout);
...
cardLayout.show(imagePanel, "1"); //this works fine
imagePanel.setLayout(new java.awt.CardLayout());
您通过以下方式将卡布局分配给imagePanel
: