如何在java graphics中向线条添加鼠标侦听器
public Line2D line2d;
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g2 = (Graphics2D) g;
g2.setColor(Color.BLACK);
g2.setStroke(new BasicStroke(2.0F));
line2d = new Line2D.Double(40, 0, 400, 400);
g2.draw(line2d);
}
@Override
public void mouseClicked(MouseEvent e) {
if(line2d.contains(e.getX(), e.getY())) {
System.out.println("Line clicked");
}
}
这种变体不起作用。有没有其他方法可以把MouseListener添加到队列中
我找到了解决办法。我认为最好在那里添加不可见多边形。抓住它 鼠标事件。因为直线不像多边形那样有可点击的区域。请参见下面的代码:
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Polygon;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.geom.Line2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class MyPanel extends JPanel implements MouseListener {
public Line2D line2d;
public Polygon pol;
public int x1 = 40;
public int y1 = 0;
public int x2 = 400;
public int y2 = 400;
public int margin = 3;
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setPreferredSize(new Dimension(500, 500));
frame.getContentPane().add(new MyPanel());
frame.pack();
frame.setVisible(true);
}
public MyPanel(){
setBackground(Color.WHITE);
addMouseListener(this);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setColor(Color.BLACK);
g2.setStroke(new BasicStroke(2.0F));
line2d = new Line2D.Double(x1, y1, x2, y2);
g2.draw(line2d);
int xPoints[] = { x1 - margin, x1 + margin, x2 + margin, x2 - margin };
int yPoints[] = { y1 + margin, y1 - margin, y2 - margin, y2 + margin };
pol = new Polygon(xPoints, yPoints, yPoints.length);
}
@Override
public void mouseClicked(MouseEvent e) {
if (pol.contains(e.getX(), e.getY())) {
System.out.println("Line clicked");
}
}
@Override
public void mouseEntered(MouseEvent e) {
// TODO Auto-generated method stub
}
@Override
public void mouseExited(MouseEvent e) {
// TODO Auto-generated method stub
}
@Override
public void mousePressed(MouseEvent e) {
// TODO Auto-generated method stub
}
@Override
public void mouseReleased(MouseEvent e) {
// TODO Auto-generated method stub
}
}
# 1 楼答案
你可以使用bessenheim(不知道如何正确发音)算法来创建一条直线
然后你只需要检查一下你是否点击了那条线
注意——这个算法不是我的主意,它是由一个叫?贝森海姆?^呵呵,多有趣的谷歌搜索^