Swing 实现简单的自定义不规则按钮组件

学习java swing，参考WilliamChen blog中关于Component的介绍，并使用Java2d 中的Paint类，自己实现了一个简单的五角星形状的自定义按钮，颜色实现渐变的效果。

特点：

五角星形状按钮

颜色渐变

相关技术：

如何自定义简单组件

如何使用Graphics2D的Paint类实现颜色渐变效果

运行界面如下：

组件代码如下：

import javax.swing.*; import java.awt.*; import java.awt.event.*; import java.util.*; /** *一个标准的五角星按钮，中间为空，通过五个点连接而成。 *颜色从上到下渐变，由topColor和bottomColor控制 * * @author sunsnowad * @date 2009-7-27 */ //TODO to be continued public class JRegularStarButton extends JComponent{ private boolean isPressed; private ArrayList<ActionListener> listeners = new ArrayList<ActionListener>(); private Polygon region;//按钮实际区域 private JRegularStarButton thisButton;//标识当前对象 private int gapTopOrLeft = 1;//最上点或最左点距边界的像素值 private int gapBottomOrRight = 1;//最下点或最右点距边界的像素值 private Color topColor = Color.yellow;//颜色渐变1 private Color bottomColor = Color.red;//颜色渐变2 public JRegularStarButton(){ isPressed = false; region = new Polygon(); thisButton = this; this.addMouseListener(new CustomMouseListener()); } public void addActionListener(ActionListener listener){ listeners.add(listener); } public void removeActionListener(ActionListener listener){ listeners.remove(listener); } protected void fireActionPerformed(ActionEvent event){ for(ActionListener listener:listeners){ listener.actionPerformed(event); } } /** * * @return StarButton的star区域 */ public Polygon getRegion(){ return region; } @Override public void paint(Graphics g){ super.paint(g); Graphics2D g2 = (Graphics2D)g; //打开反锯齿开关antialiasing g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); //GradientPaint渐变颜色控制 GradientPaint paint; if(isPressed){ paint = new GradientPaint( getWidth()/2,0,topColor,getWidth()/2,getHeight(),bottomColor); g2.setPaint(paint); g2.fillPolygon(region); } else{ paint = new GradientPaint( getWidth()/2,0,bottomColor,getWidth()/2,getHeight(),topColor); g2.setPaint(paint); g2.fillPolygon(region); } } @Override public void setBounds(int x, int y, int width, int height){ region = new Polygon(); Point[] pointSet = calcStarRegion(width,height); if(pointSet == null) return; for(Point p : pointSet){ region.addPoint(p.x, p.y); } super.setBounds(x, y, width, height); } /** * 设置按钮按下状态 * @param isPressed */ public void setPressed(boolean isPressed){ this.isPressed = isPressed; if(isShowing()) repaint(); } /** * * @return 返回按钮的按下状态 */ public boolean isPressed(){ return isPressed; } /** * @return the topColor */ public Color getTopColor() { return topColor; } /** * @param topColor the topColor to set */ public void setTopColor(Color topColor) { this.topColor = topColor; if(isShowing()) repaint(); } /** * @return the bottomColor */ public Color getBottomColor() { return bottomColor; } /** * @param bottomColor the bottomColor to set */ public void setBottomColor(Color bottomColor) { this.bottomColor = bottomColor; if(isShowing()) repaint(); } /** * * @param x * @param y * @param width * @param height * @return star区域的点集 */ private Point[] calcStarRegion(int width, int height){ int minSizeOfButton = gapTopOrLeft+gapBottomOrRight; if(height < minSizeOfButton || width < minSizeOfButton){ return null;//如果太小的按钮则不显示，太小抛出异常 } Point[] result = new Point[5]; double sin36 = Math.sin(Math.PI/5); double cos36 = Math.cos(Math.PI/5); double sin72 = Math.sin(Math.PI*2/5); double cos72 = Math.cos(Math.PI*2/5); double radius; if(width > height){ double heightOfStar = height - minSizeOfButton; radius = heightOfStar/(1+cos36); result[0] = new Point((int)(width/2.0), gapTopOrLeft); result[1] = new Point( (int)((int)(width/2.0) + radius*sin36), height-gapBottomOrRight); result[2] = new Point( (int)((int)(width/2.0) - radius*sin72), (int)((int)(height/2.0) - radius*cos72)); result[3] = new Point( (int)((int)(width/2.0) + radius*sin72), (int)((int)(height/2.0) - radius*cos72)); result[4] = new Point( (int)((int)(width/2.0) - radius*sin36), height-gapBottomOrRight); } else{ double widthOfStar = width - minSizeOfButton; radius = widthOfStar/(1+cos36); result[0] = new Point( (int)(width/2.0), (int)((int)(height/2.0)-radius)); result[1] = new Point( (int)((int)(width/2.0) + radius*sin36), (int)((int)(height/2.0) + radius*cos36)); result[2] = new Point( (int)((int)(width/2.0) - radius*sin72), (int)((int)(height/2.0) - radius*cos72)); result[3] = new Point( (int)((int)(width/2.0) + radius*sin72), (int)((int)(height/2.0) - radius*cos72)); result[4] = new Point( (int)((int)(width/2.0) - radius*sin36), (int)((int)(height/2.0) + radius*cos36)); } return result; } /** * * @author sunsnowad * 处理鼠标按下，当按下时出发所有注册的actionListener */ class CustomMouseListener extends MouseAdapter{ @Override public void mousePressed(MouseEvent e){ Point p = e.getPoint(); if(e.getButton() == MouseEvent.BUTTON1 && getRegion().contains(p)){ isPressed = true; repaint(); fireActionPerformed(new ActionEvent(thisButton, 0, null)); } } @Override public void mouseReleased(MouseEvent e){ if(e.getButton() == MouseEvent.BUTTON1){ isPressed = false; repaint(); } } } }