Java Swing 自定义图片按钮

一个按钮，如下：

已经实现了，鼠标滑过变色，鼠标单击变色，如下：

 

如果在上面设置文本button.setText("ABCDEFGHIJKLMNOPQ")，如下：

那么问题来了

（1）设置很长的文本，button不会自动伸长

（2）文本覆盖了左边的图片

解决办法：将图片切成三块

重写paintComponent方法。但是问题如下：

button.setText("ABC");
button.setFont(new Font("SansSerif", Font.BOLD, 50));

，水平可以拉伸，竖直根据算法可以拉伸，但是由于水平切成三幅图，竖直拉伸时上下线条变粗了！

所以为了美观需要切成9格图片:

另外，重写paintComponent方法时，需要注意算法，一方面考虑到字体大小对图片的拉伸，还要考虑到setPreferredSize()等方法对其影响。

代码如下：

import java.awt.Color;import java.awt.Dimension;import java.awt.FlowLayout;import java.awt.Font;import java.awt.FontMetrics;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.Insets;import java.awt.event.MouseAdapter;import java.awt.event.MouseEvent;import java.beans.PropertyChangeEvent;import java.beans.PropertyChangeListener;import java.util.HashMap;import java.util.Map;import javax.swing.ImageIcon;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JPanel;import twaver.TWaverUtil;public class ImageButton9 extends JButton {private static final long serialVersionUID = 1L;protected boolean isEnable = true;private Color color;private Color txtBgColor = Color.BLACK;private Color txtOverColor = Color.BLACK;private Color txtDisColor = Color.GRAY;private Color txtPressColor = Color.WHITE;private Color txtSelColor = Color.WHITE;    private int txtW;    private int txtH;    private int txtDescent;private String path;private Map<String, ImageIcon> map = new HashMap<String, ImageIcon>();public static final String ICON = "icon_";public static final String BG = "bg_";public static final String SEL = "sel_";public static final String OVER = "over_";public static final String PRESS = "press_";public static final String DIS = "dis_";public static final String LEFT_TOP = "left_top.png";public static final String TOP = "top.png";public static final String RIGHT_TOP = "right_top.png";public static final String LEFT = "left.png";public static final String CENTER = "center.png";public static final String RIGHT = "right.png";public static final String LEFT_BOTTOM = "left_bottom.png";public static final String BOTTOM = "bottom.png";public static final String RIGHT_BOTTOM = "right_bottom.png";public ImageButton9(String path) {this.path = path;init();invalidate();repaint();}private void init() {initMap();initUI();mouseListener();propertyListener();}private void initMap() {putIcon(BG);putIcon(SEL);putIcon(OVER);putIcon(PRESS);putIcon(DIS);setIcon(BG);}private void putIcon(String key) {map.put(key + LEFT_TOP, getIcon(key + LEFT_TOP, path));map.put(key + TOP, getIcon(key + TOP, path));map.put(key + RIGHT_TOP, getIcon(key + RIGHT_TOP, path));map.put(key + LEFT, getIcon(key + LEFT, path));map.put(key + CENTER, getIcon(key + CENTER, path));map.put(key + RIGHT, getIcon(key + RIGHT, path));map.put(key + LEFT_BOTTOM, getIcon(key + LEFT_BOTTOM, path));map.put(key + BOTTOM, getIcon(key + BOTTOM, path));map.put(key + RIGHT_BOTTOM, getIcon(key + RIGHT_BOTTOM, path));}private ImageIcon getIcon(String key, String path) {ImageIcon icon = map.get(key);if (icon != null) {return icon;}icon = TWaverUtil.getImageIcon(path + "/" + key);return icon;}private void setIcon(String key) {changeTxtColor(key);String prefix = ICON;map.put(prefix + LEFT_TOP, getIcon(key + LEFT_TOP, path));map.put(prefix + TOP, getIcon(key + TOP, path));map.put(prefix + RIGHT_TOP, getIcon(key + RIGHT_TOP, path));map.put(prefix + LEFT, getIcon(key + LEFT, path));map.put(prefix + CENTER, getIcon(key + CENTER, path));map.put(prefix + RIGHT, getIcon(key + RIGHT, path));map.put(prefix + LEFT_BOTTOM, getIcon(key + LEFT_BOTTOM, path));map.put(prefix + BOTTOM, getIcon(key + BOTTOM, path));map.put(prefix + RIGHT_BOTTOM, getIcon(key + RIGHT_BOTTOM, path));}private void changeTxtColor(String key) {if(BG.equals(key)) {color = txtBgColor;} else if(SEL.equals(key)) {color = txtSelColor;} else if(OVER.equals(key)) {color = txtOverColor;} else if(PRESS.equals(key)) {color = txtPressColor;} else if(DIS.equals(key)) {color = txtDisColor;}}private void initUI() {setMargin(new Insets(0, 0, 0, 0));setOpaque(false);setFocusable(false);setFocusPainted(false);setBorder(null);}public void mouseListener() {addMouseListener(new MouseAdapter() {@Overridepublic void mouseEntered(MouseEvent e) {if (isEnable) {setIcon(OVER);repaint();}}@Overridepublic void mouseExited(MouseEvent e) {if (isEnable) {if (isSelected()) {setIcon(SEL);} else {setIcon(BG);}repaint();}}@Overridepublic void mousePressed(MouseEvent e) {if (isEnable) {setIcon(PRESS);repaint();}}@Overridepublic void mouseReleased(MouseEvent e) {if (isEnable) {if(e.getX() >= 0 && e.getX() <= getWidth()&& e.getY() >= 0 && e.getY() <= getHeight()) {setIcon(OVER);} else {if (isSelected()) {setIcon(SEL);} else {setIcon(BG);}}repaint();}}});}private void propertyListener() {addPropertyChangeListener(new PropertyChangeListener() {@Overridepublic void propertyChange(PropertyChangeEvent e) {if("font".equals(e.getPropertyName())|| "text".equals(e.getPropertyName())) {FontMetrics metrics = getFontMetrics(getFont());txtW = metrics.stringWidth(getText());txtH = metrics.getAscent() + metrics.getDescent();txtDescent = metrics.getDescent();}}});}@Overridepublic void setSelected(boolean b) {super.setSelected(b);setIcon(SEL);}@Overridepublic void setEnabled(boolean b) {isEnable = b;if (b) {if (isSelected()) {setIcon(SEL);} else {setIcon(BG);}} else {setIcon(DIS);}super.setEnabled(b);}public void setTxtOverColor(Color txtOverColor) {this.txtOverColor = txtOverColor;}public void setTxtDisColor(Color txtDisColor) {this.txtDisColor = txtDisColor;}public void setTxtPressColor(Color txtPressColor) {this.txtPressColor = txtPressColor;}public void setTxtSelColor(Color txtSelColor) {this.txtSelColor = txtSelColor;}@Overridepublic void setForeground(Color color) {super.setForeground(color);txtBgColor = color;this.color = color;}@Overridepublic Dimension getPreferredSize() {Dimension d = super.getPreferredSize();ImageIcon left_top = map.get(ICON + LEFT_TOP);ImageIcon right_top = map.get(ICON + RIGHT_TOP);ImageIcon left_bottom = map.get(ICON + LEFT_BOTTOM);if(left_top != null && right_top != null && left_bottom != null) {int calW = txtW + left_top.getIconWidth() + right_top.getIconWidth();int calH = txtH + left_top.getIconHeight() + left_bottom.getIconHeight();int w = (int)d.getWidth();w = (w < calW) ? calW : w;int h = (int)d.getHeight();h = (h < calH) ? calH : h;d.setSize(w, h);}return d;}private boolean checkIconIsNull() {String prefix = ICON;return map.get(prefix + LEFT_TOP) == null ||        map.get(prefix + TOP) == null ||        map.get(prefix + RIGHT_TOP) == null ||        map.get(prefix + LEFT) == null ||        map.get(prefix + CENTER) == null ||        map.get(prefix + RIGHT) == null ||        map.get(prefix + LEFT_BOTTOM) == null ||        map.get(prefix + BOTTOM) == null ||        map.get(prefix + RIGHT_BOTTOM) == null;}@Overridepublic void paintComponent(Graphics g) {Graphics2D g2 = (Graphics2D) g;ImageIcon left_top = map.get(ICON + LEFT_TOP);ImageIcon top = map.get(ICON + TOP);ImageIcon right_top = map.get(ICON + RIGHT_TOP);ImageIcon left = map.get(ICON + LEFT);ImageIcon center = map.get(ICON + CENTER);ImageIcon right = map.get(ICON + RIGHT);ImageIcon left_bottom = map.get(ICON + LEFT_BOTTOM);ImageIcon bottom = map.get(ICON + BOTTOM);ImageIcon right_bottom = map.get(ICON + RIGHT_BOTTOM);int centerW = (int)getSize().getWidth();int centerH = (int)getSize().getHeight();if(!checkIconIsNull()) {centerW = (int)getSize().getWidth() - left_top.getIconWidth() - right_top.getIconWidth();centerH = (int)getSize().getHeight() - left_top.getIconHeight() - left_bottom.getIconHeight();g2.drawImage(center.getImage(), left_top.getIconWidth(), left_top.getIconHeight(), centerW, centerH, null);g2.drawImage(top.getImage(), left_top.getIconWidth(), 0,centerW, left_top.getIconHeight(), null);g2.drawImage(bottom.getImage(), left_top.getIconWidth(), left_top.getIconHeight() + centerH, centerW,left_bottom.getIconHeight(), null);g2.drawImage(left.getImage(), 0, left_top.getIconHeight(),left_top.getIconWidth(), centerH, null);g2.drawImage(right.getImage(), left_top.getIconWidth() + centerW, left_top.getIconHeight(), right_top.getIconWidth(), centerH, null);g2.drawImage(left_top.getImage(), 0, 0, left_top.getIconWidth(), left_top.getIconHeight(), null);g2.drawImage(right_top.getImage(), left_top.getIconWidth() + centerW, 0, right_top.getIconWidth(), right_top.getIconHeight(), null);g2.drawImage(left_bottom.getImage(), 0, left_top.getIconHeight() + centerH, left_bottom.getIconWidth(), left_bottom.getIconHeight(), null);g2.drawImage(right_bottom.getImage(), left_top.getIconWidth() + centerW, left_top.getIconHeight() + centerH, right_bottom.getIconWidth(), right_bottom.getIconHeight(), null);}if (getText() != null) {g2.setColor(isEnable ? color : txtDisColor);int left_position = left_top == null ? 0 : left_top.getIconWidth();int top_position = top == null ? 0 : top.getIconHeight();g2.drawString(getText(), (centerW - txtW) / 2 + left_position, (centerH + txtH) / 2 - txtDescent + top_position);}}public static void main(String[] args) {  JButton btn = new JButton(); btn.setText("ABC");ImageButton9 button = new ImageButton9("/images/actions");ImageButton9 button2 = new ImageButton9("/images/actions");ImageButton9 button3 = new ImageButton9("/images/actions");ImageButton9 button4 = new ImageButton9("/images/actions");ImageButton9 button5 = new ImageButton9("/images/actions");ImageButton9 button6 = new ImageButton9("/images/actions");JPanel panel = new JPanel();panel.setLayout(new FlowLayout());panel.add(btn);panel.add(button);panel.add(button2);panel.add(button3);panel.add(button4);panel.add(button5);panel.add(button6);JFrame frame = new JFrame();frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);frame.setSize(new Dimension(1000, 400));frame.setLocationRelativeTo(null);frame.getContentPane().add(panel);frame.setVisible(true);button.setText("ABC");button2.setText("ABC ABC ABC ABCABC");button2.setForeground(Color.BLUE);button2.setTxtSelColor(Color.WHITE);button2.setTxtPressColor(Color.GREEN);button2.setTxtOverColor(Color.RED);button3.setText("ABC ABC ABC ABC ABC");button3.setEnabled(false);button4.setText("ABC");button4.setFont(new Font("SansSerif", Font.BOLD, 22));button5.setText("ABC");button5.setSelected(true);}}

PS：这实际上是我导师写的，我写的太渣了，感觉好厉害！