import javax.swing.JFrame;
public class MyMoonFrame {
	public static void main(String[] args) {
		JFrame frame= new JFrame();
		frame.setSize(1024,768);
		frame.setLocation(100,100);
		MyMoonPanel panel=new MyMoonPanel();
		frame.add(panel);
		panel.startRun();
		frame.setVisible(true);
	}
}

package day3;
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JPanel;
public class MyMoonPanel extends JPanel{
	int x=700;
	public void startRun(){
		new Thread(){
			public void run(){
				while(true){
					//讓要去覆蓋月亮的黑圓的橫坐標坐標不斷自增 
					//這樣去接近月亮和遠離，造成月亮變化的效果 
					for (int i=0;i<1024;i++){
						x++;
						if(x>1024){
							x=0;
						}
					}
					try {
						//讓線程休眠10毫秒 
						Thread.sleep(10);
					}
					catch (InterruptedException e) {
						// TODO Auto-generated catch block 
						e.printStackTrace();
					}
					//刷新屏幕，自動調(diào)用paint()方法 
					repaint();
				}
			}
		}
		.start();
	}
	public void paint(Graphics g){
		super.paint(g);
		//設置背景 
		this.setBackground(Color.black);
		//月亮 
		g.setColor(Color.yellow);
		g.fillArc(500, 100, 200, 200, 0, 360);
		//設置將去覆蓋月亮的黑色圓 
		g.setColor(Color.black);
		g.fillArc(x, 100, 200, 200, 0, 360);
	}
}