import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
public class Main {
public static void main(String[] args) {
JPanel panel = new JPanel(new BorderLayout());
String[] values = new String[] { "One", "Two", "Three" };
JComboBox<String> comboBox = new JComboBox<>(values);
panel.add(comboBox, BorderLayout.NORTH);
JTextArea textArea = new JTextArea(2, 2);
panel.add(textArea, BorderLayout.CENTER);
JButton button = new JButton("Action");
button.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
textArea.setText((String) comboBox.getSelectedItem());
comboBox.setSelectedIndex(0);
}
});
panel.add(button, BorderLayout.SOUTH);
JFrame frame = new JFrame();
frame.add(panel);
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
【jcombobox】
