JComboBox自定义滚动条和去掉默认背景
Posted 小菜鸟yjm
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JComboBox在选择之后整个方框都会变成灰色，这一点在开发自己的界面，完全不能忍。
下面贴一下我在另外一个博客看到的解决办法，隐藏得比较深，希望能给以后遇到类似的人一些指导。传送门 点击打开链接
解决的思路就是：拿到JcomboBox的editor，然后改变JTextField的背景颜色。
private void disableFocusBackground(javax.swing.JComboBox combo)
if (combo == null)
return;
java.awt.Component comp = combo.getEditor().getEditorComponent();
if (comp instanceof javax.swing.JTextField)
javax.swing.JTextField field = (javax.swing.JTextField) comp;
field.setEditable(false);
field.setSelectionColor(field.getBackground()/* java.awt.Color.WHITE */);
combo.setEditable(true);
传入JComboBox即可。
下面简单介绍下怎么替换JComboBox丑陋的滑动条
新建一个类继承BasicScrollBarUI
package net.java.sip.communicator.impl.gui.message.yjm;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import java.io.FileInputStream;
import javax.imageio.ImageIO;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JScrollBar;
import javax.swing.plaf.basic.BasicArrowButton;
import javax.swing.plaf.basic.BasicScrollBarUI;
public class CBScrollBarUI extends BasicScrollBarUI
public Dimension getPreferredSize(JComponent c)
return new Dimension(16, 16);
// 重绘滚动条的滑块
public void paintThumb(Graphics g, JComponent c, Rectangle thumbBounds)
super.paintThumb(g, c, thumbBounds);
int tw = thumbBounds.width;
int th = thumbBounds.height;
// 重定图形上下文的原点，这句一定要写，不然会出现拖动滑块时滑块不动的现象
g.translate(thumbBounds.x, thumbBounds.y);
Graphics2D g2 = (Graphics2D) g;
GradientPaint gp = null;
gp = new GradientPaint(0, 0, new Color(124, 124, 124), tw, 0,
new Color(124, 124, 124));
g2.setPaint(gp);
g2.fillRoundRect(0, 0, tw - 1, th - 1, 5, 5);
g2.setColor(new Color(124, 124, 124));
g2.drawRoundRect(0, 0, tw - 1, th - 1, 5, 5);
// 重绘滑块的滑动区域背景
public void paintTrack(Graphics g, JComponent c, Rectangle trackBounds)
Graphics2D g2 = (Graphics2D) g;
GradientPaint gp = null;
gp = new GradientPaint(0, 0, new Color(196, 195, 194),
trackBounds.width, 0, new Color(196, 195, 194));
g2.setPaint(gp);
g2.fillRect(trackBounds.x, trackBounds.y, trackBounds.width,
trackBounds.height);
g2.setColor(new Color(196, 195, 194));
g2.drawRect(trackBounds.x, trackBounds.y, trackBounds.width - 1,
trackBounds.height - 1);
if (trackHighlight == BasicScrollBarUI.DECREASE_HIGHLIGHT)
this.paintDecreaseHighlight(g);
if (trackHighlight == BasicScrollBarUI.INCREASE_HIGHLIGHT)
this.paintIncreaseHighlight(g);
// 重绘当鼠标点击滑动到向上或向左按钮之间的区域
protected void paintDecreaseHighlight(Graphics g)
g.setColor(Color.green);
int x = this.getTrackBounds().x;
int y = this.getTrackBounds().y;
int w = 0, h = 0;
if (this.scrollbar.getOrientation() == JScrollBar.VERTICAL)
w = this.getThumbBounds().width;
h = this.getThumbBounds().y - y;
if (this.scrollbar.getOrientation() == JScrollBar.HORIZONTAL)
w = this.getThumbBounds().x - x;
h = this.getThumbBounds().height;
g.fillRect(x, y, w, h);
// 重绘当鼠标点击滑块至向下或向右按钮之间的区域
protected void paintIncreaseHighlight(Graphics g)
g.setColor(Color.blue);
int x = this.getThumbBounds().x;
int y = this.getThumbBounds().y;
int w = this.getTrackBounds().width;
int h = this.getTrackBounds().height;
g.fillRect(x, y, w, h);
protected JButton createIncreaseButton(int orientation)
return new BasicArrowButton(orientation)
// 重绘按钮的三角标记
public void paintTriangle(Graphics g, int x, int y, int size,
int direction, boolean isEnabled)
FileInputStream is;
BufferedImage img = null;
try
is = new FileInputStream("resources/images/message/群发/上三角常态.png");
img=ImageIO.read(is);
catch (Exception e)
// TODO Auto-generated catch block
e.printStackTrace();
Graphics2D g2 = (Graphics2D) g;
GradientPaint gp = null;
switch (this.getDirection())
case BasicArrowButton.SOUTH:
gp = new GradientPaint(0, 0,Color.white,
getWidth(), 0,Color.white);
break;
case BasicArrowButton.EAST:
gp = new GradientPaint(0, 0, Color.white, 0,
getHeight(), Color.white);
break;
g2.setPaint(gp);
g2.fillRect(0, 0, getWidth(), getHeight());
g2.setColor(Color.white);
g2.drawRect(0, 0, getWidth() - 1, getHeight() - 1);
g2.drawImage(img, (getWidth() - 2) / 2 - 5,
(getHeight() - 2) / 2 - 5, 13, 13, null);
;
protected JButton createDecreaseButton(int orientation)
return new BasicArrowButton(orientation)
public void paintTriangle(Graphics g, int x, int y, int size,
int direction, boolean isEnabled)
FileInputStream is;
BufferedImage img = null;
try
is = new FileInputStream("resources/images/message/群发/下三角常态.png");
img=ImageIO.read(is);
catch (Exception e)
// TODO Auto-generated catch block
e.printStackTrace();
Graphics2D g2 = (Graphics2D) g;
GradientPaint gp = null;
switch (this.getDirection())
case BasicArrowButton.NORTH:
gp = new GradientPaint(0, 0,Color.white,
getWidth(), 0, Color.white);
break;
case BasicArrowButton.WEST:
gp = new GradientPaint(0, 0,Color.white, 0,
getHeight(),Color.white);
break;
g2.setPaint(gp);
g2.fillRect(0, 0, getWidth(), getHeight());
g2.setColor(Color.white);
g2.drawRect(0, 0, getWidth() - 1, getHeight() - 1);
g2.drawImage(img, (getWidth() - 2) / 2 - 5,
(getHeight() - 2) / 2 - 5, 13, 13, null);
;
到这里只能算完成了最重要的三分之二的任务。在网上找了资料，的确看到有人这么做，继承BasicScrollBarUI。但是困惑我好久的是怎么把这个类给传到JCombBox中去。下面简单介绍下应用这个“继承者”的方法。
新建一个类
MyComboBoxUI extends BasicComboBoxUIpublic class MyComboBoxUI extends BasicComboBoxUI
public static ComponentUI createUI()
return new MyComboBoxUI();
@Override<span style="white-space:pre"> </span>//替换默认的箭头
protected JButton createArrowButton()
// JButton button = new BasicArrowButton(BasicArrowButton.EAST);
CommonButton button = new CommonButton(
"resources/images/message/群发/下拉箭头常态.png",
"resources/images/message/群发/下拉箭头掠过.png",
"resources/images/message/群发/下拉箭头掠过.png");
return button;
<span style="white-space:pre"> </span>//自定义点击右边小箭头之后的下拉框，这个方法被我忽略了很久。。。
@Override
protected ComboPopup createPopup()
ComboPopup popup = new BasicComboPopup(comboBox)
protected JScrollPane createScroller()
<span style="white-space:pre"> </span>//新建一个<span style="font-family: Arial, Helvetica, sans-serif;">JScrollPane，禁止横向滑动</span>
JScrollPane sp = new JScrollPane(list,
ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED,
ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
//sp.getVerticalScrollBar().setUI(new MyScrollBarUI());<span style="white-space:pre"> </span>//传入上面的继承BasicScrollBarUI的类
sp.getVerticalScrollBar().setUI(new CBScrollBarUI());
return sp;
;
return popup;
最后一步就是传入MyComboBoxUI
buildingBox.setUI((ComboBoxUI) MyComboBoxUI.createUI());好久都没有写博客了，因为在网上找这方面有点难找，贴出来希望能给大家有点帮助。
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