有什么方法可以将MouseListener添加到Graphic对象吗?
问题内容:
有什么方法可以将MouseListener添加到Graphic对象。
我有一个绘制椭圆的简单GUI。
我想要的是在用户单击椭圆形时处理事件
import java.awt.*;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.*;
public class Gui2 extends JFrame {
JFrame frame = new JFrame();
MyDrawPanel drawpanel = new MyDrawPanel();
public static void main(String[] args) {
Gui2 gui = new Gui2();
gui.go();
}
public void go() {
frame.getContentPane().add(drawpanel);
// frame.addMouseListener(this);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 300);
frame.setVisible(true);
}
}
class MyDrawPanel extends JComponent implements MouseListener {
public void paintComponent(Graphics g) {
int red = (int) (Math.random() * 255);
int green = (int) (Math.random() * 255);
int blue = (int) (Math.random() * 255);
Color startrandomColor = new Color(red, green, blue);
red = (int) (Math.random() * 255);
green = (int) (Math.random() * 255);
blue = (int) (Math.random() * 255);
Color endrandomColor = new Color(red, green, blue);
Graphics2D g2d = (Graphics2D) g;
this.addMouseListener(this);
GradientPaint gradient = new GradientPaint(70, 70, startrandomColor,
150, 150, endrandomColor);
g2d.setPaint(gradient);
g2d.fillOval(70, 70, 100, 100);
}
@Override
public void mouseClicked(MouseEvent e) {
if ((e.getButton() == 1)
&& (e.getX() >= 70 && e.getX() <= 170 && e.getY() >= 70 && e
.getY() <= 170)) {
this.repaint();
// JOptionPane.showMessageDialog(null,e.getX()+ "\n" + e.getY());
}
}
@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
}
}
这是有效的,但当单击位于椭圆周围的虚拟框中时会触发。
当点击完全位于椭圆形上时,有人可以帮助我触发它。
提前致谢。
问题答案:
我想到的最简单的方法是避免fillOval并使用java.awt.geom包中的几何。因此,您可以声明一个椭圆,因为看起来您绘制的椭圆是静态大小的。
class MyDrawPanel extends JComponent implements MouseListener {
Ellipse2D oval = new Ellipse2D.Double(70, 70, 100, 100);
....
}
然后在paintComponent中,使用fill(Shape)方法进行绘制。
public void paintComponent(Graphics g) {
....
Graphics2D g2d = (Graphics2D) g;
....
g2d.fill(oval);
}
然后在鼠标事件中,您可以检测单击是否在椭圆形中,如下所示:
public void mouseClicked(MouseEvent e) {
if ((e.getButton() == 1) && oval.contains(e.getX(), e.getY()) ) {
repaint();
// JOptionPane.showMessageDialog(null,e.getX()+ "\n" + e.getY());
}
}