绘制JButton圆角效果
在网上看见一篇非常好的技术文章，此文章是将JButton的四角绘制成圆角形状。这个在我们平时应用也非常多。就我而言，如果我来设计一个按钮JButton的圆角效果，我会采用：
（1）先让JButton的变成透明色
（2）然后，加入一个具有圆角的图片
现在我还是希望利用程序来绘制JButton的圆角效果，所以我将在网上看见的代码给大家一起分享。代码如下：
第一：重新继承JButton组件，然后利用Java 2D绘制图形的类将JButton组件重写。
package com.gxa.edu.test;import java.awt.AlphaComposite;import java.awt.Color;import java.awt.Font;import java.awt.GradientPaint;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.RenderingHints;import java.awt.Shape;import java.awt.event.MouseAdapter;import java.awt.event.MouseEvent;import java.awt.geom.RoundRectangle2D;import javax.swing.JButton;public class RButton extends JButton { private static final long serialVersionUID = 39082560987930759L; public static final Color BUTTON_COLOR1 = new Color(205, 255, 205); public static final Color BUTTON_COLOR2 = new Color(51, 154, 47); // public static final Color BUTTON_COLOR1 = new Color(125, 161, 237); // public static final Color BUTTON_COLOR2 = new Color(91, 118, 173); public static final Color BUTTON_FOREGROUND_COLOR = Color.WHITE; private boolean hover; public RButton(String name) { this.setText(name); setFont(new Font("system", Font.PLAIN, 12)); setBorderPainted(false); setForeground(BUTTON_COLOR2); setFocusPainted(false); setContentAreaFilled(false); addMouseListener(new MouseAdapter() { @Override public void mouseEntered(MouseEvent e) { setForeground(BUTTON_FOREGROUND_COLOR); hover = true; repaint(); } @Override public void mouseExited(MouseEvent e) { setForeground(BUTTON_COLOR2); hover = false; repaint(); } }); } @Override protected void paintComponent(Graphics g) { Graphics2D g2d = (Graphics2D) g.create(); int h = getHeight(); int w = getWidth(); float tran = 1F; if (!hover) { tran = 0.3F; } g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); GradientPaint p1; GradientPaint p2; if (getModel().isPressed()) { p1 = new GradientPaint(0, 0, new Color(0, 0, 0), 0, h - 1, new Color(100, 100, 100)); p2 = new GradientPaint(0, 1, new Color(0, 0, 0, 50), 0, h - 3, new Color(255, 255, 255, 100)); } else { p1 = new GradientPaint(0, 0, new Color(100, 100, 100), 0, h - 1, new Color(0, 0, 0)); p2 = new GradientPaint(0, 1, new Color(255, 255, 255, 100), 0, h - 3, new Color(0, 0, 0, 50)); } g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, tran)); RoundRectangle2D.Float r2d = new RoundRectangle2D.Float(0, 0, w - 1, h - 1, 20, 20); Shape clip = g2d.getClip(); g2d.clip(r2d); GradientPaint gp = new GradientPaint(0.0F, 0.0F, BUTTON_COLOR1, 0.0F, h, BUTTON_COLOR2, true); g2d.setPaint(gp); g2d.fillRect(0, 0, w, h); g2d.setClip(clip); g2d.setPaint(p1); g2d.drawRoundRect(0, 0, w - 1, h - 1, 20, 20); g2d.setPaint(p2); g2d.drawRoundRect(1, 1, w - 3, h - 3, 18, 18); g2d.dispose(); super.paintComponent(g); }}package com.gxa.edu.test;import java.awt.FlowLayout;import javax.swing.JFrame;public class TestButtonFrame extends JFrame {DepthButton b1;RButton b2;public TestButtonFrame() {super("测试");this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);this.setSize(300, 200);this.getContentPane().setLayout(new FlowLayout());b1 = new DepthButton("depthButton");b2 = new RButton("RButton");this.getContentPane().add(b1);this.getContentPane().add(b2);this.setVisible(true);}/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubnew TestButtonFrame();}}
