图像为什么会显示不出来...
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Toolkit;
import javax.swing.*;
public class sin extends JFrame {
Button button;
Container conpane;
Sinpanel sinpanel;
sin() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(500,250);
setVisible(true);
Toolkit toolkit = Toolkit.getDefaultToolkit();
Dimension scmSize = toolkit.getScreenSize();
Dimension size = getSize();
setLocation(scmSize.width / 2-size.width/2, scmSize.height / 2-size.height/2);
conpane=getContentPane();
button=new Button();
sinpanel=new Sinpanel();
conpane.add(button,BorderLayout.NORTH);
conpane.add(sinpanel,BorderLayout.CENTER);
}
public static void main(String[] args) {
new sin();
}
class Button extends JPanel
{
JButton button1;
JButton button2;
Button()
{
button1 = new JButton("显示");
button2 = new JButton("清除");
add(button1);
add(button2);
}
}
class Sinpanel extends JPanel
{
public void panit(Graphics g)
{
Dimension size=getSize();
g.drawLine(0, size.height/2 , size.width,size.height/2 );
g.drawLine(size.width/2, size.height,size.width/2,0);
System.out.print(size.height);
}
}
}