我正在尝试将 MouseListener 添加到我的自定义 JComponent。我只想在按下圆的边界时触发 MouseListener（JComponent 的绘画方法绘制一个圆）。我已经尝试使用下面的代码，但我无法让它工作（特别是在mousePressed方法中）。我该如何解决这个问题？
SSCCE：
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import javax.swing.JComponent;
import javax.swing.JFrame;
public class AffineTransformTest {
private static TransformingCanvas canvas;
public static void main(String[] args) {
JFrame frame = new JFrame();
canvas = new AffineTransformTest.TransformingCanvas();
TranslateHandler translater = new TranslateHandler();
canvas.addMouseListener(translater);
canvas.addMouseMotionListener(translater);
canvas.addMouseWheelListener(new ScaleHandler());
frame.setLayout(new BorderLayout());
frame.getContentPane().add(canvas, BorderLayout.CENTER);
frame.setSize(500, 500);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setVisible(true);
}
private static class TransformingCanvas extends JComponent {
private double translateX;
private double translateY;
private double scale;
TransformingCanvas() {
translateX = 0;
translateY = 0;
scale = 1;
setOpaque(true);
setDoubleBuffered(true);
}
@Override
public void paint(Graphics g) {
AffineTransform tx = new AffineTransform();
tx.translate(translateX, translateY);
tx.scale(scale, scale);
Graphics2D ourGraphics = (Graphics2D) g;
ourGraphics.setColor(Color.WHITE);
ourGraphics.fillRect(0, 0, getWidth(), getHeight());
ourGraphics.setTransform(tx);
ourGraphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
ourGraphics.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING,
RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
ourGraphics.setColor(Color.BLACK);
ourGraphics.fillOval(50, 50, 50, 50);
}
}
private static class TranslateHandler implements MouseListener,
MouseMotionListener {
private int lastOffsetX;
private int lastOffsetY;
public void mousePressed(MouseEvent e) {
lastOffsetX = e.getX();
lastOffsetY = e.getY();
double width = canvas.scale * 50;
double height = canvas.scale * 50;
double x = (AffineTransformTest.canvas.getWidth() - width) / 2;
double y = (AffineTransformTest.canvas.getHeight() - height) / 2;
Rectangle2D.Double bounds = new Rectangle2D.Double(x, y, width, height);
System.out.println(bounds + " " + e.getPoint());
if (bounds.contains(e.getPoint())) {
System.out.println("Click!");
}
}
public void mouseDragged(MouseEvent e) {
int newX = e.getX() - lastOffsetX;
int newY = e.getY() - lastOffsetY;
lastOffsetX += newX;
lastOffsetY += newY;
canvas.translateX += newX;
canvas.translateY += newY;
canvas.repaint();
}
public void mouseClicked(MouseEvent e) {
}
public void mouseEntered(MouseEvent e) {
}
public void mouseExited(MouseEvent e) {
}
public void mouseMoved(MouseEvent e) {
}
public void mouseReleased(MouseEvent e) {
}
}
private static class ScaleHandler implements MouseWheelListener {
public void mouseWheelMoved(MouseWheelEvent e) {
if (e.getScrollType() == MouseWheelEvent.WHEEL_UNIT_SCROLL) {
canvas.scale += (.1 * e.getWheelRotation());
canvas.scale = Math.max(0.00001, canvas.scale);
canvas.repaint();
}
}
}
}