Java Swing - 如何附加動作事件在JComboBox箭頭JButton
我們想知道如何附加動作事件在JComboBox箭頭JButton。
import java.awt.Component;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
public class Main {
private static JButton getButtonSubComponent(Container container) {
if (container instanceof JButton) {
return (JButton) container;
} else {
Component[] components = container.getComponents();
for (Component component : components) {
if (component instanceof Container) {
return getButtonSubComponent((Container) component);
}
}
}
return null;
}
public static void main(String[] args) {
JComboBox<String> combo = new JComboBox<>(new String[]{ "One", "Two", "Three" });
JButton arrowBtn = getButtonSubComponent(combo);
if (arrowBtn != null) {
arrowBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("arrow button pressed");
}
});
}
JFrame f = new JFrame();
f.getContentPane().add(combo);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.pack();
f.setVisible(true);
}
}
【jcombobox】
