为什么我的这段代码不显示 ----圆 ????
import java.awt.*;
import javax.swing.*;public class Test { public static void main (String[] args) {
JFrame win;
Container contentpane;
Graphics g;
win = new JFrame("TimeKeeper");
win.setSize(500,500);
win.setLocation(100,100);
win.setVisible(true);
contentpane = win.getContentPane();
g = contentpane.getGraphics();
g.setColor(Color.BLACK);
g.drawLine(50,50,100,100);
}
}
import java.awt.*;
import javax.swing.*;public class Test { public static void main (String[] args) {
JFrame win;
Container contentpane;
Graphics g;
win = new JFrame("TimeKeeper");
win.setSize(500,500);
win.setLocation(100,100);
win.setVisible(true);
contentpane = win.getContentPane();
g = contentpane.getGraphics();
g.setColor(Color.BLACK);
g.drawLine(50,50,100,100);
}
}
import java.awt.*;
import javax.swing.*;public class Test
{
public static void main (String[] args)
{
JFrame win;
Container contentpane;
MyPanel panel = new MyPanel();
win = new JFrame("TimeKeeper");
win.setSize(500,500);
win.setLocation(100,100);
contentpane = win.getContentPane();
contentpane.add(panel);
win.setVisible(true);
}
}class MyPanel extends JPanel
{
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.setColor(Color.BLACK);
g.drawLine(50,50,100,100);
}
}
你原来那样,因为显示会调用到paint方法,所以你画的直线又看不到了