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import java.awt.Color;
import java.awt.Graphics;
import java.awt.Panel;
import javax.swing.JFrame;
public class test {
private JFrame f = new JFrame(" Hello Out There!");
private Panel p = new Panel();
public void paintComponent() {
f.add(p);
f.setSize(170, 170);
f.setBackground(Color.blue);
f.setVisible(true); //如果把这句话放到Graphics g = p.getGraphics(); 后面
p.setForeground(Color.red); //g为什么在运行的时候就变成空的了呢?
Graphics g = p.getGraphics();
f.setVisible(true);
g.drawArc(30, 40, 50, 60, 70, 80);
g.fillArc(30, 40, 50, 60, 70, 80);
}
public static void main(String args[]) {
test guiWindow = new test();
guiWindow.paintComponent();
}
}
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Test
{
private JFrame frame = new JFrame(" Hello Out There!");
private MyPane pane = new MyPane();
public void initGUI()
{
pane.setOpaque(false);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(pane);
frame.setSize(170, 170);
frame.setLocationRelativeTo(null);
frame.getContentPane().setBackground(Color.BLUE);
frame.setVisible(true);
}
public static void main(String args[])
{
Test guiWindow = new Test();
guiWindow.initGUI();
}
}
class MyPane extends JPanel
{
private static final long serialVersionUID = -147774397142687220L;
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
g.setColor(Color.RED);
g.drawArc(30, 40, 50, 60, 70, 80);
g.fillArc(30, 40, 50, 60, 70, 80);
}
}