components3.java

Swing入门必看 Swing Demo

/*
 * @(#)Components3.java 2007-4-27
 * Copyright 2007 AIC. All rights reserved. 
 */
package components;

import java.awt.event.*;

import javax.swing.*;
import javax.swing.event.*;


/**
 * Demonstrating JComboBox, JList, JSlider
 * 
 * Note: 
 * 		Their construtors and methods, listeners.
 * 
 * @author Henry Zhu
 */
public class Components3 extends AbstractComponents {

	private static final long serialVersionUID = 1L;

	private JComboBox comboBox;
	
	private JList list;
	
	private int count;
	
	private JLabel label;
	
	private JSlider slider;

	protected void initComponents(Box box) {
		String[] items = {"one", "two", "three"};

		/* =================JComboBox================= */

		// # JComboBox constructors
		comboBox = new JComboBox();
		comboBox = new JComboBox(items);

		// # JComboBox methods
		comboBox.addItem("four");
		comboBox.addItem("five");
		comboBox.setMaximumRowCount(3);
//		int index = comboBox.getSelectedIndex();
//		String item = (String)comboBox.getSelectedItem();

		// # JComboBox Event Listener (anonymous inner class)
		comboBox.addItemListener(new ItemListener() { 

			public void itemStateChanged(ItemEvent e) {
				// if combo box selected, change button's background color
				if ( e.getStateChange() == ItemEvent.SELECTED ) {
					String str = "Selected index: " + comboBox.getSelectedIndex()
							+ "\nSelected item: " + comboBox.getSelectedItem();
					JOptionPane.showMessageDialog(Components3.this, str);
				} /*else {
					String str = "Old item: " + e.getItem();
					JOptionPane.showMessageDialog(Components3.this, str);
				}*/
				
			}
			
		});
		
		box.add(comboBox);
		box.add(Box.createVerticalStrut(20));

		/* ===================JList=================== */

		// # JList constructors		
		list = new JList();
//		list = new JList(items);
		
		// # JList methods
		list.setListData(items);		
		list.setVisibleRowCount(5);
		list.setFixedCellWidth(200);
//		list.setFixedCellHeight(20);	
		list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION );
							// ListSelectionModel.SINGLE_SELECTION
							// ListSelectionModel.SINGLE_INTERVAL_SELECTION
							// ListSelectionModel.MULTIPLE_INTERVAL_SELECTION
//		int index = list.getSelectedIndex();
//		int[] indices = list.getSelectedIndices();
//		Object value = list.getSelectedValue();
//		Object[] values = list.getSelectedValues();	
		count = 0;
		// # JList Event Listener (anonymous inner class)
		list.addListSelectionListener( new ListSelectionListener() {

			public void valueChanged(ListSelectionEvent e) {
				if (!e.getValueIsAdjusting()) { // List values have changed
				
					String str = (String)list.getSelectedValue();
					JOptionPane.showMessageDialog(Components3.this, str);
					label.setText("Message :" + count++ + str);
				}
			} 

		 }); 

		box.add(list);
		box.add(Box.createVerticalStrut(20));
		label = new JLabel("Message:");
		box.add(label);
		

		/* ==================JSlider================== */

		// # JSlider constructors
//		slider = new JSlider(10, 100);
		slider = new JSlider(SwingConstants.HORIZONTAL, 10, 100, 20);
		
		// # JSlider methods
		slider.setMajorTickSpacing(5);
		slider.setPaintTicks(true);
//		int value = slider.getValue();
		
		// # JSlider Event Listener (anonymous inner class)
		slider.addChangeListener(new ChangeListener() {

			public void stateChanged(ChangeEvent e) {
				list.setFixedCellHeight(slider.getValue());
			}
			
		});
		
		box.add(slider);
		box.add(Box.createVerticalStrut(20));
	}

	/**
	 * 
	 * @param title
	 */
	public Components3(String title) {
		super(title);
	}

	public static void main(String args[]) {
		// create Components3 object
		String title = "Components: JComboBox, JList, JSlider";
		new Components3(title);
	}
}