用JSlider设置Color（未达到效果）

Question

我那个小例子的目的是通过red、blue、green三个块来设置Color的三分量，
可是老达不到预期的结果！//源码
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;public class MyColorSliderTest
{
public static void main(String[] args)
{
MyColorSliderFrame frame=new MyColorSliderFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}/**
   MyColorSliderFrame
*/
class MyColorSliderFrame extends JFrame
{
public MyColorSliderFrame()
{
setTitle("My Color Slider Test");
setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);

//初始化暂存颜色的变量
red=green=blue=256/2;

//sliderPanel
sliderPanel=new JPanel();
sliderPanel.setLayout(new GridLayout(3,1));

//事件监听器
listener=new ChangeListener()
{
public void stateChanged(ChangeEvent event)
{
JSlider slider=(JSlider)event.getSource();
int value=slider.getValue();

//这种算法，我并不是很认同，但又找不到时别的方法
if((value!=red)&&(value==blue)&&(value==green))
{
red=value;
demoPanel.setBackground
(new Color(value,green,blue));
}
else
{
if((value!=green)&&(value==red)
&&(value==blue))
{
green=value;
demoPanel.setBackground
(new Color(red,value,blue));
}
else
{
blue=value;
demoPanel.setBackground
(new Color(red,green,value));
}
}
}
};

//redSlider
JSlider redSlider=new JSlider(0,255,256/2);
addSlider(redSlider,"red");

//greenSlider
JSlider greenSlider=new JSlider(0,255,256/2);
addSlider(greenSlider,"green");

//blueSlider
JSlider blueSlider=new JSlider(0,255,256/2);
addSlider(blueSlider,"blue");

demoPanel=new JPanel();
demoPanel.setBackground(new Color(128,128,128));
add(sliderPanel,BorderLayout.CENTER);
add(demoPanel,BorderLayout.SOUTH);
}

//添加Slider
public void addSlider(JSlider s,String description)
{
s.addChangeListener(listener);
JPanel panel=new JPanel();
panel.add(s);
panel.add(new JLabel(description));
sliderPanel.add(panel);
}

private JPanel demoPanel;
private JPanel sliderPanel;
private ChangeListener listener;
private int red,green,blue;

public static final int DEFAULT_WIDTH=400;
public static final int DEFAULT_HEIGHT=400;

}

Answer 1

你的那个处理颜色的算法确实不怎么对,只要把你程序里面的"事件监听器"以下的程序换成我这个就好使了,代码如下:
//事件监听器
listener=new ChangeListener()
{
int redValue = 256/ 2, greenValue = 256 / 2, blueValue = 256 /2;
public void stateChanged(ChangeEvent event)
{
JSlider slider=(JSlider)event.getSource();
//这种算法，我并不是很认同，但又找不到时别的方法
if(slider == redSlider)
redValue = redSlider.getValue();
if(slider == greenSlider)
greenValue = greenSlider.getValue();
if(slider == blueSlider)
redValue = blueSlider.getValue();
 demoPanel.setBackground(new Color(redValue, greenValue, blueValue));
}
};//redSlideraddSlider(redSlider,"red");//greenSlideraddSlider(greenSlider,"green");//blueSlideraddSlider(blueSlider,"blue");demoPanel=new JPanel();
demoPanel.setBackground(new Color(128,128,128));
add(sliderPanel,BorderLayout.CENTER);
add(demoPanel,BorderLayout.SOUTH);
}//添加Slider
public void addSlider(JSlider s,String description)
{
s.addChangeListener(listener);
JPanel panel=new JPanel();
panel.add(s);
panel.add(new JLabel(description));
sliderPanel.add(panel);
}private JPanel demoPanel;
private JPanel sliderPanel;
private ChangeListener listener;
private int red,green,blue;
private JSlider redSlider=new JSlider(0,255,256/2);
private JSlider greenSlider=new JSlider(0,255,256/2);
private JSlider blueSlider=new JSlider(0,255,256/2);
public static final int DEFAULT_WIDTH=400;
public static final int DEFAULT_HEIGHT=400;}

Answer 2

这是改完以后的完成程序如下:
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;public class MyColorSliderTest
{
public static void main(String[] args)
{
MyColorSliderFrame frame=new MyColorSliderFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}/**
   MyColorSliderFrame
*/
class MyColorSliderFrame extends JFrame
{
public MyColorSliderFrame()
{
setTitle("My Color Slider Test");
setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);//初始化暂存颜色的变量
red=green=blue=256/2;//sliderPanel
sliderPanel=new JPanel();
sliderPanel.setLayout(new GridLayout(3,1));//事件监听器
listener=new ChangeListener()
{
int redValue = 256/ 2, greenValue = 256 / 2, blueValue = 256 /2;
public void stateChanged(ChangeEvent event)
{
JSlider slider=(JSlider)event.getSource();
//这种算法，我并不是很认同，但又找不到时别的方法
if(slider == redSlider)
redValue = redSlider.getValue();
if(slider == greenSlider)
greenValue = greenSlider.getValue();
if(slider == blueSlider)
redValue = blueSlider.getValue();
 demoPanel.setBackground(new Color(redValue, greenValue, blueValue));
}
};//redSlideraddSlider(redSlider,"red");//greenSlideraddSlider(greenSlider,"green");//blueSlideraddSlider(blueSlider,"blue");demoPanel=new JPanel();
demoPanel.setBackground(new Color(128,128,128));
add(sliderPanel,BorderLayout.CENTER);
add(demoPanel,BorderLayout.SOUTH);
}//添加Slider
public void addSlider(JSlider s,String description)
{
s.addChangeListener(listener);
JPanel panel=new JPanel();
panel.add(s);
panel.add(new JLabel(description));
sliderPanel.add(panel);
}private JPanel demoPanel;
private JPanel sliderPanel;
private ChangeListener listener;
private int red,green,blue;
private JSlider redSlider=new JSlider(0,255,256/2);
private JSlider greenSlider=new JSlider(0,255,256/2);
private JSlider blueSlider=new JSlider(0,255,256/2);
public static final int DEFAULT_WIDTH=400;
public static final int DEFAULT_HEIGHT=400;}