[英]How to repaint properly in JPanel inside JFrame
stackoverflow社区! 我正在用JAVA制作基于GUI的小型游戏。 我现在有一些麻烦。 为了让您对我的程序有基本的了解,
我有一个窗口,首先显示菜单(JPanel)。 当我点击“开始游戏”按钮时。 它进入另一个我可以玩游戏的JPanel。 ![menu_window] [1]
我有一个计时器在处理定期移动的小子弹。 每次计时器工作时,面板都会重新绘制项目符号。 我可以看到repaint方法有效,但是它不会删除以前的跟踪。
![在此处输入图片描述] [2]
这是我的主班
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Main {
private final int window_x_size = 500;
private final int window_y_size = 500;
private JFrame frame;
private JPanel Menu;
private Game myGame = new Game();//extends from JPanel
private JButton startButton = new JButton("Game Start");
private JButton exitButton = new JButton("Game Exit");
private JButton showRank = new JButton("Rank");
private JButton OneOnOne = new JButton("One on One");
private ActionListener MyButtonListener = new MyButtonListener();
public class MyButtonListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
Object source = e.getSource();
if (source == startButton) {
frame.remove(Menu);
frame.setContentPane(myGame);
frame.validate();
frame.repaint(); // prefer to write this always.
} else if (source == exitButton) {
System.exit(1);
} else if (source == showRank) {
} else {// one on one
}
}
}
public Main() {
frame = new JFrame();
frame.setBackground(Color.white);
frame.setSize(window_x_size, window_y_size);
frame.setTitle("My First GUI Game");
frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
Menu = new JPanel();
startButton.addActionListener(MyButtonListener);
exitButton.addActionListener(MyButtonListener);
showRank.addActionListener(MyButtonListener);
OneOnOne.addActionListener(MyButtonListener);
Menu.setLayout(new GridLayout(4, 1));
Menu.add(startButton);
Menu.add(OneOnOne);
Menu.add(showRank);
Menu.add(exitButton);
frame.setContentPane(Menu);
frame.setVisible(true);
}
public static void main(String[] args) {
/*
* This is the most important part of your GUI app, never forget
* to schedule a job for your event dispatcher thread :
* by calling the function, method or constructor, responsible
* for creating and displaying your GUI.
*/
SwingUtilities.invokeLater(new Runnable()
{
@Override
public void run()
{
new Main();
}
});
}
}
这是我的游戏课
import java.awt.Graphics;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.Random;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
import javax.swing.Timer;
public class Game extends JPanel {
private Random rnd = new Random();
private ActionListener MyBulletListener = new BulletListener();
public KeyListener myKeyListen = new MyKeyListener();
Timer bullet_timer;
private boolean IsExplosion = false;
private ImageIcon spacecraftImg = new ImageIcon("spacecraft.png");
private Rectangle spacecraftBox = new Rectangle(5, 10,
spacecraftImg.getIconWidth(), spacecraftImg.getIconHeight());
private ImageIcon explosionImg = new ImageIcon("explosion.png");
private ImageIcon bulletImg = new ImageIcon("bullet.png");
private Rectangle bulletBox = new Rectangle(70, 200,
bulletImg.getIconWidth(), bulletImg.getIconHeight());
private MySound explosion_sound = new MySound();
public Game() {
addKeyListener(myKeyListen);
bullet_timer = new Timer(500, MyBulletListener);
bullet_timer.start();
}
public class MyKeyListener implements KeyListener {
private int x;
private int y;
@Override
public void keyPressed(KeyEvent e) {
// TODO Auto-generated method stub
int keyCode = e.getKeyCode();
if (keyCode == 37) {
x = -10;
y = 0;
} else if (keyCode == 38) {
x = 0;
y = -10;
} else if (keyCode == 39) {
x = 10;
y = 0;
} else {
x = 0;
y = 10;
}
if (spacecraftBox.x + x < 0
|| spacecraftBox.x + x > 500
|| spacecraftBox.y + y < 0
|| spacecraftBox.y + y > 500) {
} else {
move_plane(x, y);
repaint();
}
}
@Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
@Override
public void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub
}
}
public class BulletListener implements ActionListener {
private int x;
private int y;
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
Object source = e.getSource();
if (source == bullet_timer) {
int dir = rnd.nextInt(4);
if (dir == 0) {// move left
x = -10;
y = 0;
} else if (dir == 1) {// move right
x = 10;
y = 0;
} else if (dir == 2) {// move up
x = 0;
y = -10;
} else {// move down
x = 0;
y = 10;
}
if (bulletBox.x + x < 0
|| bulletBox.x + x > 500
|| bulletBox.y + y < 0
|| bulletBox.y + y > 500) {
} else {
move_bullets(x, y);
repaint();
}
}
}
}
@Override
public void paint(Graphics g) {
g.drawImage(bulletImg.getImage(), (int) bulletBox.getX(),
(int) bulletBox.getY(), null);
g.drawImage(spacecraftImg.getImage(), (int) spacecraftBox.getX(),
(int) spacecraftBox.getY(), null);
if (IsExplosion) {
g.drawImage(explosionImg.getImage(), (int) bulletBox.getX(),
(int) bulletBox.getY(), null);
MySound.play();
IsExplosion = false;
}
}
public void move_plane(int x, int y) {
spacecraftBox.translate(x, y);
if (spacecraftBox.intersects(bulletBox)) {
IsExplosion = true;
}
}
public void move_bullets(int x, int y) {
bulletBox.translate(x, y);
if (spacecraftBox.intersects(bulletBox)) {
IsExplosion = true;
}
}
}
另外,我添加了KeyListener,但是它不起作用。 我不知道如何解决它。
我尝试使用Google搜索该问题。 我尝试了以主要班级为重点的游戏面板,但是没有用。
我将衷心感谢您的帮助。
最好的祝福,
Dongseop
这几乎总是由于您的绘画方法未调用super的绘画方法来清除脏像素而引起的。 由于您要覆盖绘画,因此需要调用super.paint(g);
作为绘画替代中的第一个方法调用。
其他事宜:
paintComponent(Graphics g)
,因为这将使您的动画具有自动双重缓冲,并使动画更加平滑。 再次,调用super.paintComponent(g);
在您的方法中覆盖。 Java Key Bindings Tutorial
以了解有关如何使用它们的官方教程。
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