level 1
btwwdn
楼主
想用滚动条控制圆的大小，在JPanel内画圆
但每次画圆都不会清除前一个圆，请帮忙看下代码
import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class yuan extends Applet {
Scrollbar s1 = new Scrollbar(0, 0, 1, 0, 100);//滚动条
JPanel p1 = new JPanel();
JPanel p2 = new JPanel(new BorderLayout());
int v1 = 10;//圆半径
public yuan() throws HeadlessException
{
s1.addAdjustmentListener(new AdjustmentListener() {
public void adjustmentValueChanged(AdjustmentEvent e) {
v1=e.getValue();
Graphics g = p1.getGraphics();
draw(g);
}
});
}
public void init() {
p2.add(s1,BorderLayout.NORTH);
p1.setPreferredSize(new Dimension(255, 255));
p2.add(p1,BorderLayout.SOUTH);
add(p2);
}
private void draw(Graphics g) {
g.drawOval(100,100,v1,v1);
}
}
