我创建了一个简单的Java Swing程序,每次用户点击鼠标时它会在窗口中输出一个3*3的正方形。即使用户点击多次,这些正方形也会保留在窗口中。该程序编译和运行都很好,但是当用户在窗口中点击时,正方形绘制的位置远离鼠标指针。我已经思考了很长时间,到底需要怎么改变程序才能让正方形在每次点击时都与指针精确对应呢?非常感谢任何帮助!
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.util.ArrayList;
import javax.swing.JComponent;
import javax.swing.JFrame;
public class ClickCloud extends JComponent {
final ArrayList<Point2D> points = new ArrayList<Point2D>();
public void addPoint(Point2D a) {
points.add(a);
}
public void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
for (int i = 0; i < points.size(); i++) {
Point2D aPoint = points.get(i);
g2.draw(new Rectangle2D.Double(aPoint.getX(), aPoint.getY(), 3, 3));
}
}
public static void main(String[] args) {
final ClickCloud cloud = new ClickCloud();
JFrame aFrame = new JFrame();
class ClickListen implements MouseListener {
@Override
public void mouseClicked(MouseEvent arg0) {
}
@Override
public void mouseEntered(MouseEvent arg0) {
}
@Override
public void mouseExited(MouseEvent arg0) {
}
public void mousePressed(MouseEvent arg0) {
cloud.addPoint(arg0.getPoint());
cloud.repaint();
}
@Override
public void mouseReleased(MouseEvent arg0) {
}
}
aFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
aFrame.setSize(500, 500);
aFrame.add(cloud);
aFrame.addMouseListener(new ClickListen());
aFrame.setVisible(true);
}
}