comboboxexample.java

《JAVA程序设计教程》源代码

//ComboBoxExample.java

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

public class ComboBoxExample
{  
	public static void main(String[] args)
	{  
		ComboBoxFrame frame = new ComboBoxFrame();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.show();
	}
}

class ComboBoxFrame extends JFrame
{
	public ComboBoxFrame()
	{
		setTitle("ComboBoxExample");
		setSize(WIDTH, HEIGHT);

		Container contentPane = getContentPane();
		
		//建立容纳组合框的面板
		jobsPanel = new JPanel();

		//新建组合框
		jobsBox = new JComboBox();
		jobsBox.setEditable(true);;
		jobsBox.addItem("job1");
		jobsBox.addItem("job2");
		jobsBox.addItem("job3");
		jobsBox.addItem("job4");
		jobsBox.addItem("job5");
		jobsBox.addItem("job6");

		//增加事件监听器
		jobsBox.addActionListener(new jobsListener());
		jobsPanel.add(choiceLabel);
		jobsPanel.add(jobsBox);

		//建立容纳文本域的面板
		JPanel textPanel = new JPanel();
		//新建文本域
		myTextField = new JTextField("", 15);
		textPanel.add(choosedLabel, BorderLayout.NORTH);
		textPanel.add(myTextField, BorderLayout.CENTER);

		contentPane.add(jobsPanel, BorderLayout.NORTH);
		contentPane.add(textPanel, BorderLayout.CENTER);
	}

	//事件监听器
	private class jobsListener
		implements ActionListener
	{
		public void actionPerformed(ActionEvent event)
		{
			StringBuffer tempSeletedText = new StringBuffer("");
			Object selectedJob = jobsBox.getSelectedItem();
			String str = (String)selectedJob;
			tempSeletedText.append(str);
			myTextField.setText(tempSeletedText.toString());
		}
	}

	public static final int WIDTH = 300;
	public static final int HEIGHT = 150;
	public static final JLabel choosedLabel=new JLabel("Job has been choosed:");
	public static final JLabel choiceLabel=new JLabel("Job will be choosed:");

	private JTextField myTextField;
	private JComboBox jobsBox;
	private JPanel jobsPanel;
}