Java自定义JSlider UI

JSlider作为Swing中提供的滑标组件， 以图形方式在有界区间内通过移动滑块来选择值，滑块可以显示主刻度标记和次刻度标记。大量应用于如播放器中的音量设定等领域中。

但是JSlider本身提供的UI样式很单调，不足以满足用户的审美需求，往往需要我们自行重构其UI。

下面我给出一个简单的例子。

package org.loon.framework.swing.test;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Polygon;
import java.awt.Rectangle;
import java.awt.RenderingHints;

import javax.swing.Box;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.WindowConstants;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

/***/ /**
*<p>
*Title:LoonFramework
*</p>
*<p>
*Description:
*</p>
*<p>
*Copyright:Copyright(c)2007
*</p>
*<p>
*Company:LoonFramework
*</p>
*
*@authorchenpeng
*@email：[email protected]
*@version0.1
*/
public class ExampleSlider extends JPanel ... {
/***//**
*
*/
privatestaticfinallongserialVersionUID=1L;

publicExampleSlider()...{
//设定布局器
super(newBorderLayout());
//设定监听器
ChangeListenerlistener=newChangeListener()...{
publicvoidstateChanged(ChangeEvente)...{
if(e.getSource()instanceofJSlider)...{
System.out.println("刻度:"
+((JSlider)e.getSource()).getValue());
}
}
};
//设定JSlider1
JSliders1=newJSlider(0,100,0);
//注入自定义ui
s1.setUI(newMySliderUI());
//主刻度
s1.setMajorTickSpacing(10);
//次刻度
s1.setMinorTickSpacing(5);
//设定为显示
s1.setPaintTicks(true);
s1.setPaintLabels(true);
//监听slider1
s1.addChangeListener(listener);
//设定JSlider2
JSliders2=newJSlider(0,100,0);
//使用MetalSliderUI为ui
s2.setUI(newjavax.swing.plaf.metal.MetalSliderUI()...{
protectedvoidpaintHorizontalLabel(Graphicsg,intv,Componentl)...{
JLabellbl=(JLabel)l;
lbl.setForeground(Color.green);
super.paintHorizontalLabel(g,v,lbl);
}
});

s2.setForeground(Color.BLUE);
s2.setMajorTickSpacing(10);
s2.setMinorTickSpacing(5);
s2.setPaintTicks(true);
s2.setPaintLabels(true);
s2.addChangeListener(listener);

//使用盒式容器
Boxbox=Box.createVerticalBox();
box.add(Box.createVerticalStrut(5));
box.add(s1);
box.add(Box.createVerticalStrut(5));
box.add(s2);
box.add(Box.createVerticalGlue());
add(box,BorderLayout.CENTER);
add(Box.createHorizontalStrut(5),BorderLayout.WEST);
add(Box.createHorizontalStrut(5),BorderLayout.EAST);
//设定窗体大小
setPreferredSize(newDimension(240,100));
}

publicstaticvoidmain(String[]args)...{
EventQueue.invokeLater(newRunnable()...{
publicvoidrun()...{
createUI();
}
});
}

publicstaticvoidcreateUI()...{
JFrameframe=newJFrame("音量刻度设置");
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.getContentPane().add(newExampleSlider());
frame.setResizable(false);
frame.pack();
//居中
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}

class MySliderUI extends javax.swing.plaf.metal.MetalSliderUI ... {
/***//**
*绘制指示物
*/
publicvoidpaintThumb(Graphicsg)...{
Graphics2Dg2d=(Graphics2D)g;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
//填充椭圆框为当前thumb位置
g2d.fillOval(thumbRect.x,thumbRect.y,thumbRect.width,
thumbRect.height);
//也可以帖图(利用鼠标事件转换image即可体现不同状态)
//g2d.drawImage(image,thumbRect.x,thumbRect.y,thumbRect.width,thumbRect.height,null);
}

/***//**
*绘制刻度轨迹
*/
publicvoidpaintTrack(Graphicsg)...{
intcy,cw;
RectangletrackBounds=trackRect;
if(slider.getOrientation()==JSlider.HORIZONTAL)...{
Graphics2Dg2=(Graphics2D)g;
cy=(trackBounds.height/2)-2;
cw=trackBounds.width;

g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2.translate(trackBounds.x,trackBounds.y+cy);

//背景设为灰色
g2.setPaint(Color.GRAY);
g2.fillRect(0,-cy,cw,cy*2);

inttrackLeft=0;

inttrackRight=0;

trackRight=trackRect.width-1;

intmiddleOfThumb=0;

intfillLeft=0;

intfillRight=0;

//坐标换算
middleOfThumb=thumbRect.x+(thumbRect.width/2);
middleOfThumb-=trackRect.x;

if(!drawInverted())...{
fillLeft=!slider.isEnabled()?trackLeft:trackLeft+1;
fillRight=middleOfThumb;
}else...{
fillLeft=middleOfThumb;
fillRight=!slider.isEnabled()?trackRight-1
:trackRight-2;
}
//设定渐变
g2.setPaint(newGradientPaint(0,0,newColor(0,100,100),cw,0,
newColor(0,255,100),true));
g2.fillRect(0,-cy,fillRight-fillLeft,cy*2);

g2.setPaint(slider.getBackground());
Polygonpolygon=newPolygon();
polygon.addPoint(0,cy);
polygon.addPoint(0,-cy);
polygon.addPoint(cw,-cy);
g2.fillPolygon(polygon);
polygon.reset();

g2.setPaint(Color.WHITE);
g2.drawLine(0,cy,cw-1,cy);

g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_OFF);
g2.translate(-trackBounds.x,-(trackBounds.y+cy));
}else...{
super.paintTrack(g);
}
}
}

效果图：