swing自定义组件之BUTTON

1、Swing自定义组件之ButtonGUI组件要完成的任务有2个，展现与业务。对于按钮来说，文本、图标、边框、背景属于展现层，而这些元素在按钮不同状态下会不尽相同，一般来说至少有4种状态下的展现：普通、鼠标放在其上、被按下、被禁用，也就是按钮应该具备这4种状态。下面给出的示例是swing实现的自定义按钮。通常swing自定义组件继承javax.swing.JComponent并重写protected void paintComponent(Graphics g方法实现自定义绘制。 重写paintComponent方法时通常要先去掉super.paintComponent(g，因为父方法调用会绘制

2、背景色。不妨先看一下源代码中的调用过程。在JComponent.java中paintComponent(Graphics g方法定义如下： protected void paintComponent(Graphics g if (ui != null Graphics scratchGraphics = (g = null ? null : g.create(;try ui.update(scratchGraphics, this;finally scratchGraphics.dispose(;其中ui的声明如下protected transient ComponentUI ui;然后转向C

3、omponentUI的update(Graphics g, JComponent c方法：public void update(Graphics g, JComponent c if (c.isOpaque( g.setColor(c.getBackground(;g.fillRect(0, 0, c.getWidth(,c.getHeight(;paint(g, c;可见如果发现组件是非透明的，就绘制背景，可以看出swing组件的setBackground方法如何绘制背景的。一般简单的自定义组件，你可以只通过重写paintComponent方法来实现绘制，对于一般的组件这已经足够。对于自定义

4、按钮一般的原则是准备4张背景图对应上述4种状态，这4种状态都可通过鼠标*来感知，当状态改变时，调用repaint(使Button重绘。除了背景，按钮文本、图标等的改变一样也必须调用repaint(来刷新。然后重要的一点是你必须重写public Dimension getPreferredSize(来获得按钮的最佳尺寸。getPreferredSize方法对于布局管理器来说至关重要，布局管理器会通过getPreferredSize的判断组件的最佳大小，并进行布局。而对于本范例而言，getPreferredSize的大小只和背景图片大小有关。对于业务，尽量做到前台界面与后来业务分离。你可以自定义按

5、钮动作*器来实现，本例是沿用swing的Action实现，当鼠标抬起时，构造一个ActionEvent对象，然后交给Action成员的actionPerformed(ActionEvent e处理。代码如下：/* Created on 2007年11月11日, 下午6:30* To change this template, choose Tools | Template Manager* and open the template in the editor.*/package demo.swing;import java.awt.AlphaComposite;import java.awt

6、.Color;import java.awt.Container;import java.awt.Dimension;import java.awt.Font;import java.awt.FontMetrics;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.RenderingHints;import java.awt.Shape;import java.awt.event.ActionEvent;import java.awt.event.MouseEvent;import java.awt.font

7、.TextAttribute;import java.awt.font.TextLayout;import java.awt.geom.AffineTransform;import java.util.HashMap;import javax.swing.Action;import javax.swing.Icon;import javax.swing.JComponent;import javax.swing.SwingConstants;import javax.swing.SwingUtilities;import javax.swing.event.MouseInputListener

8、;/* 为需要具备专业外观的按钮提供方便的实现。通过此类提供的若干方法可轻松实现专业外观。* author 电玩*/public final class ImageButton extends JComponent implementsMouseInputListener /* 通常状态下的背景图片*/private Icon backgroundImage;/* 通常状态下的最佳尺寸*/private Dimension preferredSize;/* 鼠标光标在上方时的背景图片*/private Icon rolloverBackgroundImage;/* 鼠标光标在上方时的最佳尺寸*

9、/private Dimension rolloverPreferredSize;/* 按钮被按下时的背景图片*/private Icon pressedBackgroundImage;/* 按钮被按下时的最佳尺寸*/private Dimension pressedPreferredSize;/* 按钮被禁止时的背景图片*/private Icon disabledBackgroundImage;/* 按钮被禁止时的最佳尺寸*/private Dimension disabledPreferredSize;/* 当前按钮的最佳尺寸*/private volatile Dimension cu

10、rrentSize;/* 通常状态下按钮的图标*/private Icon icon;/* 按钮被禁止时的图标*/private Icon disabledIcon;/* 按钮图标出现的位置*/private IconOrientation iconOrientation = IconOrientation.WEST;/* 按钮的默认尺寸*/private static final Dimension DEFAULT_SIZE = new Dimension(100, 25;/* 水平偏移量*/private int horizontalOffset = DEFAULT_HORIZONTAL_

11、OFFSET;/* 默认的水平偏移量*/private static final int DEFAULT_HORIZONTAL_OFFSET = 4;/* 垂直偏移量*/private int verticalOffset = DEFALUT_VERTICAL_OFFSET;/* 默认的垂直偏移量*/private static final int DEFALUT_VERTICAL_OFFSET = 2;/* 显示在按钮上的文字*/private String text;/* 按钮文本的字体*/private Font font;/* 按钮文本的默认字体*/private static fin

12、al Font DEFAULT_FONT = Font.decode("Dialog-Plain-14"/* 按钮被禁止时候文字的颜色*/private Color disabledForeground;/* 默认的按钮被禁止时文本的颜色*/private final Color DEFAULT_DISABLED_FOREGROUND = new Color(192, 192, 192;/* 按钮的状态*/private volatile Status status = Status.DEFAULT;/* 按钮的颜色透明度*/private volatile float a

13、lpha = 1.0f;private static HashMap< RenderingHints.Key, Object> renderingHints;/* 按钮执行的动作*/private Action action;static renderingHints = new HashMap(;renderingHints.put(RenderingHints.KEY_ALPHA_INTERPOLATION,RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY;renderingHints.put(RenderingHints.KEY

14、_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON;renderingHints.put(RenderingHints.KEY_COLOR_RENDERING,RenderingHints.VALUE_COLOR_RENDER_QUALITY;renderingHints.put(RenderingHints.KEY_DITHERING,RenderingHints.VALUE_DITHER_DISABLE;renderingHints.put(RenderingHints.KEY_FRACTIONALMETRICS,RenderingHints.V

15、ALUE_FRACTIONALMETRICS_ON;renderingHints.put(RenderingHints.KEY_INTERPOLATION,RenderingHints.VALUE_INTERPOLATION_BICUBIC ;renderingHints.put(RenderingHints.KEY_STROKE_CONTROL,RenderingHints.VALUE_STROKE_PURE;renderingHints.put(RenderingHints.KEY_TEXT_ANTIALIASING,RenderingHints.VALUE_TEXT_ANTIALIAS_

16、ON;/* 创建一个ImageButton按钮的实例 */public ImageButton( currentSize = DEFAULT_SIZE;addMouseListener(this;addMouseMotionListener(this;/* 设置常规状态下按钮的背景。调用该方法会影响到按钮在常规状态下的最佳尺寸，* 由传入的图标参数对应的图标尺寸决定* param backgroundImage 常规状态下背景图标对象* throws java.lang.IllegalArgumentException 如果传入的参数为null*/public void setBackgrou

17、ndImage(Icon backgroundImage throws IllegalArgumentException if (backgroundImage = null throw new IllegalArgumentException("backgroundImage can't be null"this.backgroundImage = backgroundImage;preferredSize = new Dimension(backgroundImage.getIconWidth(,backgroundImage.getIconHeight(;cu

18、rrentSize = preferredSize;/* 设置被禁用状态下按钮的背景。调用该方法会影响到按钮在禁用状态下的最佳尺寸，* 由传入的图标参数对应的图标尺寸决定* param disabledBackgroundImage 禁用状态下背景图标对象* throws java.lang.IllegalArgumentException 如果传入的参数为null*/public void setDisabledBackgroundImage(Icon disabledBackgroundImage throws IllegalArgumentException if (disabledBa

19、ckgroundImage = null throw new IllegalArgumentException("disabledBackgroundImage can't be null"this.disabledBackgroundImage = disabledBackgroundImage;disabledPreferredSize = new Dimension(disabledBackgroundImage.getIconWidth(, disabledBackgroundImage.getIconHeight(;/* 设置在被按下状态时按钮的背景。调用

20、该方法会影响到按钮在被按下状态时的最佳尺寸，* 由传入的图标参数对应的图标尺寸决定* param pressedBackgroundImage 被按下时的背景图标对象* throws java.lang.IllegalArgumentException 如果传入的参数为null*/public void setPressedBackgroundImage(Icon pressedBackgroundImagethrows IllegalArgumentException if (pressedBackgroundImage = null throw new IllegalArgumentExc

21、eption("pressedBackgroundImage can't be null"this.pressedBackgroundImage = pressedBackgroundImage;pressedPreferredSize = new Dimension(pressedBackgroundImage.getIconWidth(, pressedBackgroundImage.getIconHeight(;/* 设置鼠标指针在其上方时按钮的背景。调用该方法会影响到按钮在鼠标指针在其上方* 时的最佳尺寸，由传入的图标参数对应的图标尺寸决定* param r

22、olloverBackgroundImage 鼠标指针在其上方时的背景图标对象* throws java.lang.IllegalArgumentException 如果传入的参数为null*/public void setRolloverBackgroundImage(Icon rolloverBackgroundImage throws IllegalArgumentException if (rolloverBackgroundImage = null throw new IllegalArgumentException("rolloverBackgroundImage can

23、't be null"this.rolloverBackgroundImage = rolloverBackgroundImage;rolloverPreferredSize = new Dimension(rolloverBackgroundImage.getIconWidth(, rolloverBackgroundImage.getIconHeight(;/* 设置水平偏移量。* param horizontalOffset 水平偏移量* throws java.lang.IllegalArgumentException 如果参数小于0，抛出此异常*/public vo

24、id setHorizontalOffset(int horizontalOffset throws IllegalArgumentExceptionif(horizontalOffset < 0 throw new IllegalArgumentException("horizontalOffset must >=0"this.horizontalOffset = horizontalOffset;/* 设置垂直偏移量* param verticalOffset 垂直偏移量* throws java.lang.IllegalArgumentException

25、如果参数小于0，抛出此异常*/public void setVerticalOffset(int verticalOffset throws IllegalArgumentExceptionif(verticalOffset < 0 throw new IllegalArgumentException("verticalOffset must >=0"this.verticalOffset = verticalOffset;/* 设置按钮的图标* param icon 图标对象* throws java.lang.IllegalArgumentException

26、 如果传入的参数为null，抛出此异常*/public synchronized void setIcon(Icon icon throws IllegalArgumentException if(icon = null throw new IllegalArgumentException("icon can't be null"this.icon = icon;/* 设置按钮在被禁用时显示的图标* param disabledIcon 图标对象* throws java.lang.IllegalArgumentException 如果传入的参数为null，抛出此异

27、常*/public synchronized void setDisabledIcon(Icon disabledIcon throws IllegalArgumentException if(disabledIcon = null throw new IllegalArgumentException("disabledIcon can't be null"this.disabledIcon = disabledIcon;public void setIconOrientation(IconOrientation iconOrientation throws Ill

28、egalArgumentExceptionif(iconOrientation = null throw new IllegalArgumentException("iconOrientation can't be null"this.iconOrientation = iconOrientation;public void setDisabledForeground(Color disabledForeground this.disabledForeground = disabledForeground;/* 设置按钮的透明度*/public synchroniz

29、ed void setAlpha(float alphathrows IllegalArgumentExceptionif (alpha < 0f | alpha > 1.0f throw new IllegalArgumentException("alpha value must between 0.0 and 1.0"this.alpha = alpha;repaint(;/* 设置按钮显示的文本* param text 显示的文本字符串*/public synchronized void setText(String text if (text != nu

30、ll this.text = text;repaint(;/* 返回按钮的当前字体，如果之前没有设置字体，则返回默认字体* return 按钮的当前字体*/public Font getFont( if(font = null return DEFAULT_FONT;return font;/* 设置按钮的当前字体* param font 字体实例*/public void setFont(Font font this.font = font;super.setFont(font;/* 指定这个按钮的动作* param action 按钮的动作*/public void setAction(A

31、ction action this.action = action;/* 覆盖JComponent.setEnabled(boolean enabled，设置是否按钮可用或被禁止* param enabled 如果按钮可用则为true，否则为false* see java.awt.Component#isEnabled*/Overridepublic void setEnabled(boolean enabled super.setEnabled(enabled;if (isEnabled( != enabled if (disabledPreferredSize != null&&a

32、mp; !disabledPreferredSize.equals(currentSize currentSize = disabledPreferredSize;revalidate(;/* 绘制按钮边框* param g 图形上下文* deprecated 此方法只在内部被调用，外部不要显式调用*/Overrideprotected void paintBorder(Graphics g /* 绘制子组件* param g 图形上下文* deprecated 此方法只在内部被调用，外部不要显式调用*/Overrideprotected void paintChildren(Graphics

33、 g /* 绘制按钮* param g 图形上下文* deprecated 此方法只在内部被调用，外部不要显式调用*/Overrideprotected void paintComponent(Graphics g Graphics2D g2d = (Graphics2D g.create(;g2d.addRenderingHints(renderingHints;if(alpha < 1.0f g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER,alpha;drawBackgroundImage(g2d

34、;drawIcon(g2d;drawText(g2d;g2d.dispose(;private void drawIcon(final Graphics2D g2d Icon currentIcon = isEnabled( ? icon : disabledIcon;if(currentIcon = null return;int w = currentIcon.getIconWidth(;int h = currentIcon.getIconHeight(;int offsetX = 0;int offsetY = 0;switch (iconOrientation case WEST:o

35、ffsetX = horizontalOffset;offsetY = getHeight( / 2 - h / 2;break;case EAST:offsetX = getWidth( - horizontalOffset - w;offsetY = getHeight( / 2 - h / 2;break;case NORTH:offsetX = getWidth( / 2 - w / 2;offsetY = verticalOffset;break;case SOUTH:offsetX = getWidth( / 2 - w / 2;offsetY = getHeight( - ver

36、ticalOffset - h;break;case NORTH_WEST:offsetX = horizontalOffset;offsetY = verticalOffset;break;case NORTH_EAST:offsetX = getWidth( - horizontalOffset - w;offsetY = verticalOffset;break;case SOUTH_WEST:offsetX = horizontalOffset;offsetY = getHeight( - verticalOffset - h;break;case SOUTH_EAST:offsetX

37、 = getWidth( - horizontalOffset - w;offsetY = getHeight( - verticalOffset - h;break;case CENTER:offsetX = getWidth( / 2 - w / 2;offsetY = getHeight( / 2 - h / 2;break;currentIcon.paintIcon(this,g2d,offsetX,offsetY;private void drawBackgroundImage(final Graphics2D g2d if (!isEnabled( if (disabledBack

38、groundImage != null disabledBackgroundImage.paintIcon(this, g2d, 0, 0;return;switch (status case ROLLOVER:if (rolloverBackgroundImage != null rolloverBackgroundImage.paintIcon(this, g2d, 0, 0; else if (backgroundImage != null backgroundImage.paintIcon(this, g2d, 0, 0;break;case PRESSED:if (pressedBa

39、ckgroundImage != null pressedBackgroundImage.paintIcon(this, g2d, 0, 0; else if (backgroundImage != null backgroundImage.paintIcon(this, g2d, 0, 0;break;case PRESSED_EXIT:default:if (backgroundImage != null backgroundImage.paintIcon(this, g2d, 0, 0;break;private void drawText(final Graphics2D g2d if

40、(text = null | text.isEmpty( return;Font font = getFont(;FontMetrics fm = getFontMetrics(font;TextLayout textLayout = new TextLayout(text, font, g2d.getFontRenderContext(;AffineTransform affineTransform = AffineTransform.getTranslateInstance(getWidth( - fm.stringWidth(text / 2,getHeight( / 2 + fm.ge

41、tHeight( / 4;Shape textShape = textLayout.getOutline(affineTransform;if(isEnabled( g2d.setPaint(getForeground(; else g2d.setPaint(disabledForeground != null ? disabledForeground: DEFAULT_DISABLED_FOREGROUND;g2d.fill(textShape;g2d.draw(textShape;/* 鼠标单击事件的处理* param e 鼠标事件* deprecated 此方法只在内部被调用，外部不要显

42、式调用*/public void mouseClicked(MouseEvent e /* 按钮按下时的处理* param e 鼠标事件* deprecated 此方法只在内部被调用，外部不要显式调用*/public void mousePressed(MouseEvent e if (!isEnabled( return; else if(!SwingUtilities.isLeftMouseButton(e return;status = Status.PRESSED;repaint(;if (pressedPreferredSize != null&& !pressedP

43、referredSize.equals(currentSize currentSize = pressedPreferredSize;revalidate(;/* 鼠标抬起时的处理* param e 鼠标事件* deprecated 此方法只在内部被调用，外部不要显式调用*/public void mouseReleased(MouseEvent e if (!isEnabled( return; else if(!SwingUtilities.isLeftMouseButton(e return;if (e.getX( > 0 && e.getY( > 0 &am

44、p;& e.getX( < getPreferredSize(.width&& e.getY( < getPreferredSize(.height status = Status.ROLLOVER;if (rolloverPreferredSize != null&& !rolloverPreferredSize.equals(currentSize currentSize = rolloverPreferredSize;try doAction(e; catch (Exception ex ex.printStackTrace(; else status = Status.DEFAULT;if (preferredSize != null && !preferredSize.equals(currentSize currentSize = preferredSize;repaint(;revalidate(;/* 鼠标进入时的处理* param e 鼠标事件* deprecated 此方法只在内部被调用，外部不要显式调用*/public void mouseEntered(MouseEvent e if (!isEnabled( r