Java Swing - 如何處理JComboBox下拉彈出事件
我們想知道如何處理JComboBox下拉彈出事件。
import java.awt.FlowLayout;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.event.PopupMenuEvent;
import javax.swing.event.PopupMenuListener;
public class Main {
public static void main(String[] args) {
JComboBox c = new JComboBox();
c.addPopupMenuListener(new PopupMenuListener() {
@Override
public void popupMenuCanceled(PopupMenuEvent e) {
System.out.println(e.getSource());
}
@Override
public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {
System.out.println(e.getSource());
}
@Override
public void popupMenuWillBecomeVisible(PopupMenuEvent e) {
System.out.println(e.getSource());
}
});
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().setLayout(new FlowLayout());
f.getContentPane().add(c);
f.pack();
f.setVisible(true);
}
}
【jcombobox】
