java入門第七天 鍵盤控制小球移動和變態作業的答案（其實也沒啥）

鍵盤控制小球移動

package day07;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

import javax.swing.JFrame;
import javax.swing.JPanel;

/**
 * 演示鍵盤事件
 */
public class MyKeyBallDemo {
	public static void main(String [] args){
		//1.
		JFrame frame = new JFrame();
		frame.setSize(400,500);
		frame.setLocationRelativeTo(null);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		//2
		MyKeyBallPanel mkbp = new MyKeyBallPanel();
		frame.add(mkbp);
		//添加監聽
		mkbp.addKeyListener(mkbp);
		frame.addKeyListener(mkbp);
		frame.setVisible(true);
	}
}
class MyKeyBallPanel extends JPanel implements KeyListener{
	int x = 30 ;
	int y = 30 ;
	public void paint(Graphics g){
		super.paint(g);
		g.setColor(Color.blue);
		g.fillOval(x, y, 30, 30);
	}
	//鍵盤按下
	public void keyPressed(KeyEvent e) {
		//獲取按下的鍵值
		//char c = e.getKeyChar();
		int code = e.getKeyCode();
		System.out.println(code);
		//判斷按下的鍵值
		if(code == KeyEvent.VK_UP){
			//小球往上走
			y --;
		}else if(code == KeyEvent.VK_DOWN){
			//往下
			y++;
		}else if(code == KeyEvent.VK_LEFT){
			//往左
			x --;
		}else if(code == KeyEvent.VK_RIGHT){
			//往右
			x ++;
		}
		//重繪
		repaint();
		
	}
	public void keyReleased(KeyEvent e) {
		// TODO Auto-generated method stub
		
	}
	public void keyTyped(KeyEvent e) {
		// TODO Auto-generated method stub
		
	}
}

作業的答案

package day07;
/**
 * for循環打印各種三角形
 */
public class HomeWorkForDemo {
	public static void main(String [] args){
		//打印直角倒三角(左對齊)
		printF(6);
		//打印直角倒三角(右對齊)
		printFF(6);
		//打印等邊三角形
		printFFF(6);
	}
	//直角倒三角(左對齊)
	public static void printF(int len ){
		for(int i=0 ;i