java 存储键值对_Java Swing - 如何存储键值对
import java.awt.Component;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.plaf.basic.BasicComboBoxRenderer;
public class Main {
public Main() {
JComboBox comboBox = new JComboBox();
comboBox.addItem(new Item(1, "-"));
comboBox.addItem(new Item(2, "X"));
comboBox.addItem(new Item(3, "Y"));
comboBox.setMaximumRowCount(3);
comboBox.setPrototypeDisplayValue(" None of the above ");
comboBox.addActionListener(e -> {
JComboBox c = (JComboBox) e.getSource();
Item item = (Item) c.getSelectedItem();
System.out.println(item.getId() + " : " + item.getDescription());
});
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(comboBox);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
new Main();
}
}
class ItemRenderer extends BasicComboBoxRenderer {
@Override
public Component getListCellRendererComponent(JList list, Object value,
int index, boolean isSelected, boolean cellHasFocus) {
super.getListCellRendererComponent(list, value, index, isSelected,
cellHasFocus);
if (value != null) {
Item item = (Item) value;
setText(item.getDescription().toUpperCase());
}
if (index == -1) {
Item item = (Item) value;
setText("" + item.getId());
}
return this;
}
}
class Item {
private int id;
private String description;
public Item(int id, String description) {
this.id = id;
this.description = description;
}
public int getId() {
return id;
}
public String getDescription() {
return description;
}
@Override
public String toString() {
return description;
}
}