我尝试在JCombobox箭头JButton上附加动作事件。
所以我做了一个自定义的ComboBoxUI:
public class CustomBasicComboBoxUI extends BasicComboBoxUI {
public static CustomBasicComboBoxUI createUI(JComponent c) {
return new CustomBasicComboBoxUI ();
}
@Override
protected JButton createArrowButton() {
JButton button=super.createArrowButton();
if(button!=null) {
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// arrow button clicked
}
});
}
return button;
}
}
问题在于组合框的外观不同,看起来很古老。 为什么?我只在同一个箭头按钮上添加一个监听器......
感谢。
答案 0 :(得分:4)
也许问题是由于您期望JComboBox不是BasicComboBoxUI而是另一种外观和感觉,可能是MetalComboBoxUI。
您可以从现有的JComboBox对象中提取JButton组件,而不是创建新的CustomBasicComboBoxUI对象吗?即,
import java.awt.Component;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class ComboBoxArrowListener {
private static void createAndShowUI() {
String[] data = {"One", "Two", "Three"};
JComboBox combo = new JComboBox(data);
JPanel panel = new JPanel();
panel.add(combo);
JButton arrowBtn = getButtonSubComponent(combo);
if (arrowBtn != null) {
arrowBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("arrow button pressed");
}
});
}
JFrame frame = new JFrame("ComboBoxArrowListener");
frame.getContentPane().add(panel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
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) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}