jcomboboxdemo.java

Swing入门必看 Swing Demo

package components;

import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.util.Vector;

import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;

public class JComboBoxDemo extends JFrame {

	private static final long serialVersionUID = 1L;
	public JComboBoxDemo() {
		Student[] students = new Student[9];
		Vector<Student> vector = new Vector<Student>();
		
		for (int i = 0; i < students.length; i++) {
			students[i] = new Student("yiyi" + i, 20 + i);
			vector.add(students[i]);
		}		
		final JComboBox comboBox = new JComboBox(vector);
		Container container = getContentPane();
		comboBox.setMaximumRowCount(5);
		comboBox.setSelectedIndex(1);
		comboBox.setSelectedItem(students[3]);
		final JLabel label = new JLabel();
		comboBox.addItemListener(new ItemListener() {
			public void itemStateChanged(ItemEvent e) {
				if (e.getStateChange() == ItemEvent.SELECTED)
					label.setText("" + comboBox.getSelectedIndex() + ", "
							+ comboBox.getSelectedItem());
			}
		});
		
		label.setText("" + comboBox.getMaximumRowCount());
		container.setLayout(new FlowLayout());
		container.add(comboBox);
		container.add(label);
		
		setSize(400,400);
		setVisible(true);
		
	}
	

	public static void main(String[] args) {
		JComboBoxDemo application = new JComboBoxDemo();
		application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

	}

}