jsliderdemo.java

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

public class JSliderDemo extends JFrame implements ChangeListener 
{
    /** sliderRed: 调整红色值
     * sliderGreen: 调整绿色值
     * sliderBlue: 调整蓝色值
     */
    private JSliderEx sliderRed, sliderGreen, sliderBlue;
    private JPanel colorPanel, sliderPanel;
    private Color color;
    
    public JSliderDemo()
    {
        super("JSlider 组件");
        setSize(400, 300);       
        Container container = getContentPane();       
		try
		{  //设置外观
			UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
		}catch(Exception e){}
        
		//创建颜色面板colorPanel
		colorPanel = new JPanel();
        
        container.add(colorPanel, BorderLayout.CENTER);
        
		//创建存放三个JSlider组件的面板sliderPanel
        sliderPanel = new JPanel();
        sliderPanel.setBackground(Color.YELLOW);
        sliderPanel.setPreferredSize(new Dimension(400, 150));
        sliderPanel.setLayout(new GridLayout(3, 1, 5, 5));
        
        //创建JSlider组件
        sliderRed = new JSliderEx(this, 0, 255);
        sliderGreen = new JSliderEx(this, 0, 255);
        sliderBlue = new JSliderEx(this, 0, 255);
        
        //设置组件背景色
        sliderRed.setBackground(Color.RED);
        sliderGreen.setBackground(Color.GREEN);
        sliderBlue.setBackground(Color.BLUE);
        
        sliderPanel.add(sliderRed);
        sliderPanel.add(sliderGreen);
        sliderPanel.add(sliderBlue);
        
        container.add(sliderPanel, BorderLayout.SOUTH);
        
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
    
    public static void main(String[] args)
    {
        JSliderDemo application = new JSliderDemo();
    }
    
    //处理ChangeEvent事件,当用户移动滑动杆时,面板colorPanel的背景色会随之改变
    public void stateChanged(ChangeEvent event)
    {
    	color = new Color(sliderRed.getValue(), sliderGreen.getValue(),
    			          sliderBlue.getValue());
    	colorPanel.setBackground(color);
    }
    
    class JSliderEx extends JSlider
    {
    	public JSliderEx(ChangeListener listener, int min, int max)
    	{
    		super(min, max);
    		//设置是否在JSlider加上刻度
    		setPaintTicks(true);
    		//设置大刻度之间的距离
    	    setMajorTickSpacing(15);
    	    //设置与小刻度之间的距离
    	    setMinorTickSpacing(3);
    	    //设置是否数字标记，若设为true，则JSlider刻度上就会有数值出现
    	    setPaintLabels(true);   	    
    	    addChangeListener(listener); //添加事件监视器
    	}
    }
}