Java实现进度条JProgressBar设置颜色，变色进度条

如果程序中没有加载其他界面风格主题，进度条的颜色很容易修改，直接setBackground()

bar.setBackground(Color.WHITE); bar.setForeground(Color.BLACK);

最近做项目遇到一个问题，由于项目程序中加载了setBackground()失效了。我查了一下API，重写了JProgressBar中的setUI()方法，自己重新定义了一个ProgressBarUI

import java.awt.Color; import java.awt.Graphics; import javax.swing.JComponent; import javax.swing.JProgressBar; import javax.swing.plaf.basic.BasicProgressBarUI; public class ProgressUI extends BasicProgressBarUI { private JProgressBar jProgressBar; private int progressvalue; private Color forecolor; ProgressUI(JProgressBar jProgressBar,Color forecolor) { this.jProgressBar = jProgressBar; this.forecolor=forecolor; } @Override protected void paintDeterminate(Graphics g, JComponent c) { this.jProgressBar.setBackground(new Color(255, 255, 255)); this.jProgressBar.setForeground(forecolor); super.paintDeterminate(g, c); } }

然后在新建JProgressBar中，重写setUI()方法，加载该ProgressBarUI

progressbar=new JProgressBar(){ @Override public void setUI(ProgressBarUI ui) { // TODO Auto-generated method stub super.setUI(new ProgressUI(this,new Color(255, 201, 14)));//这个颜色就是我们要设置的进度条颜色 } };如果想要实现变色进度条的话，则需要在ProgressBarUI方法中对进度条的value值进行判断，然后更改颜色

import java.awt.Color; import java.awt.Graphics; import javax.swing.JComponent; import javax.swing.JProgressBar; import javax.swing.plaf.basic.BasicProgressBarUI; public class ProgressUI extends BasicProgressBarUI { private JProgressBar jProgressBar; private int progressvalue; private Color forecolor; ProgressUI(JProgressBar jProgressBar,Color forecolor) { this.jProgressBar = jProgressBar; this.forecolor=forecolor; } @Override protected void paintDeterminate(Graphics g, JComponent c) { progressvalue=this.jProgressBar.getValue(); if(progressvalue<20){ this.jProgressBar.setForeground(Color.BLUE); } else if(progressvalue<40){ this.jProgressBar.setForeground(Color.YELLOW); } else if(progressvalue<60){ this.jProgressBar.setForeground(Color.RED); } else if(progressvalue<80){ this.jProgressBar.setForeground(Color.GREEN); } else{ this.jProgressBar.setForeground(Color.CYAN); } super.paintDeterminate(g, c); } }