それはまだ同じで、Fruit クラスでは ID が使用されていないと表示されます。
真実ではありません。私のクラスItem
は期待どおりに機能します。あなたのケースでは、より良いヘルプをすぐに投稿する必要SSCCE
がありますItemRenderer
。
import java.awt.Component;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.SwingUtilities;
import javax.swing.plaf.basic.BasicComboBoxRenderer;
public class SelectedComboBoxID {
public SelectedComboBoxID() {
JComboBox comboBox = new JComboBox();
comboBox.addItem(new Item(1, "-"));
comboBox.addItem(new Item(2, "Snowboarding"));
comboBox.addItem(new Item(3, "Rowing"));
comboBox.addItem(new Item(4, "Knitting"));
comboBox.addItem(new Item(5, "Speed reading"));
comboBox.addItem(new Item(6, "Pool"));
comboBox.addItem(new Item(7, "None of the above"));
comboBox.setMaximumRowCount(3);
comboBox.setPrototypeDisplayValue(" None of the above ");
comboBox.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
JComboBox comboBox = (JComboBox) e.getSource();
Item item = (Item) comboBox.getSelectedItem();
System.out.println(item.getId() + " : " + item.getDescription());
}
});
//comboBox.setRenderer(new ItemRenderer());
JFrame frame = new JFrame("MyComboEg");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(comboBox);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private class ItemRenderer extends BasicComboBoxRenderer {
private static final long serialVersionUID = 1L;
@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;
}
}
private 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;
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
SelectedComboBoxID selectedComboBoxID = new SelectedComboBoxID();
}
});
}
}