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创建圆形的SWING BUTTON(1)
CREATING ROUND SWING BUTTONS This tip is about round Swing buttons. Actually, the information in this tip applies to a button of any arbitrary shape but to keep the discussion simple, we're just going to use a round shape. There are two things you need to do when creating a round button. The first is to override the appropriate painting methods in order to paint the round shape. The second is to set things up so that the button responds only when you click within the round button (not just within the rectangle that contains the round button). Here's an example program that implements a round button: import Java.awt.*;import Java.awt.geom.*;import Javax.swing.*;public class RoundButton extends JButton {public RoundButton(String label) { super(label);// These statements enlarge the button so that it // becomes a circle rather than an oval. Dimension size = getPreferredSize(); size.width = size.height = Math.max(size.width, size.height); setPreferredSize(size);// This call causes the JButton not to paint // the background.// This allows us to paint a round background. setContentAreaFilled(false);}// Paint the round background and label.protected void paintComponent(GraphiCS g) { if (getModel().isArmed()) {// You might want to make the highlight color // a property of the RoundButton class.g.setColor(Color.lightGray); } else {g.setColor(getBackground()); } g.fillOval(0, 0, getSize().width-1, getSize().height-1);// This call will paint the label and the // focus rectangle. super.paintComponent(g);}// Paint the border of the button using a simple stroke.protected void paintBorder(GraphiCS g) { g.setColor(getForeground()); g.drawOval(0, 0, getSize().width-1, getSize().height-1);}// Hit detection.Shape shape;public boolean contains(int x, int y) {// If the button has changed size, // make a new shape object. if (shape == null !shape.getBounds().equals(getBounds())) {shape = new Ellipse2D.Float(0, 0,getWidth(), getHeight()); } return shape.contains(x, y);}// Test routine.public static void main(String[] args) {// Create a button with the label "Jackpot". JButton button = new RoundButton("Jackpot"); button.setBackground(Color.green);// Create a frame in which to show the button. JFrame frame = new JFrame(); frame.getContentPane().setBackground(Color.yellow); frame.getContentPane().add(button); frame.getContentPane().setLayout(new FlowLayout()); frame.setSize(150, 150); frame.setVisible(true);}}
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