java实现画图和清屏功能.

Posted 2023-03-02

要求做一个界面,界面上有画图按钮和清屏按钮,单击画图按钮可以显示出一个圆,单击清屏功能可以将画出的圆清除掉. NOTE:希望给出详细的程序过程,并能够编译通过的.

import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;/**
* @author Administrator
*
*/
@SuppressWarnings("serial")
public class DrawTest extends JFrame final DrawPanel pnlImg = new DrawPanel();

public DrawTest()
init();


private void init()
setLayout(new GridLayout(2, 1));
add(pnlImg);
final JButton btnDraw = new JButton("画图");
btnDraw.addActionListener(new ActionListener()
@Override
public void actionPerformed(ActionEvent e)
pnlImg.setDrawRadius(200);
pnlImg.setDrawOval(true);

);
final JButton btnClear = new JButton("清屏");
btnClear.addActionListener(new ActionListener()
@Override
public void actionPerformed(ActionEvent e)
pnlImg.setDrawOval(false);

);
final JPanel pnlButton = new JPanel(new GridLayout(1, 2));
pnlButton.add(btnDraw);
pnlButton.add(btnClear);
add(pnlButton);
setSize(800, 600);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);


public static void main(String [] args) throws Exception
javax.swing.SwingUtilities.invokeAndWait(new Runnable()
public void run()
new DrawTest().setVisible(true);

);


class DrawPanel extends JPanel

boolean flag;
int radius = 100;

public void setDrawOval(boolean flag)
this.flag = flag;
repaint();


public void setDrawRadius(int radius)
this.radius = radius;


public void paintComponent(Graphics g)
super.paintComponent(g);
Rectangle rect = getBounds();
if (flag && rect.width > radius && rect.height > radius)
g.drawOval((rect.width - radius) / 2, (rect.height - radius) / 2, radius, radius);



参考技术A 清屏很简单的，只要用背景色画一个和屏一样大的矩形就可以了。

另一方法： 清屏的办法在AWT和swing中可以这样实现:g.clearRect(0, 0, width, height); g 就是 Graphics 对象