我正在用 java 练习一些 OOP。
我只想用一些图形对象编写一个游戏,但我想用一些类来构建它。
整体布局应该是这样的:
MainClass -> new MainPanel(扩展 JPanel)->new StartWindow(扩展包含游戏循环的抽象 GameWindow)
这样我应该能够创建 StartWindow、Level1Window、Level2Window 等等。 我的 StartWindow 现在应该绘制第一层的布局。 StartWindow 将创建其他对象(Player、Enemy 等),稍后将负责绘制它们自己。
所以我想创建类似“每个对象都有责任绘制自己”的东西
我希望我能说清楚这应该如何工作。 问题是,我不知道如何委派这项任务。
我的代码现在看起来像这样:
public class MainClass extends JFrame implements ActionListener {
//..... other stuff
public MainClass () {
MainPanel mainPanel = new MainPanel();
}
//.... other stuff
}
class MainPanel extends JPanel {
private GameWindow currentWindow;
public MainPanel () {
currentWindow = new StartWindow(this);
}
public void paintComponent(Graphics g) {
g.drawRect (10, 10, 200, 200); // <-- can see on the window
}
}
abstract class GameWindow {
// contains game loop and update functions and so on
}
public class StartWindow extends GameWindow {
GamePanel _parentWindow;
public StartWindow(GamePanel parentWindow) {
super();
_parentWindow = parentWindow;
}
public void paintComponent(Graphics g) {
//Does not work
g.drawRect (20, 20, 100, 100);
}
}
“_parentWindow”包含 MainPanel,因此我应该拥有在其面板上绘制所需的所有信息,但我只是不知道该怎么做。
编辑: 工作的最小示例:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class MainClass extends JFrame implements ActionListener {
public static void main(String[] args)
{
System.out.println("Program Window1");
MainClass glt = new MainClass();
glt.setVisible(true);
}
//..... other stuff
public MainClass () {
super("Fixed Timestep Game Loop Test");
Container cp = getContentPane();
cp.setLayout(new BorderLayout());
JPanel p = new JPanel();
p.setLayout(new GridLayout(1,2));
System.out.println("Program Window2");
MainPanel gamePanel= new MainPanel();
cp.add(gamePanel, BorderLayout.CENTER);
cp.add(p, BorderLayout.SOUTH);
setSize(500, 500);
}
//.... other stuff
@Override
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
}
}
class MainPanel extends JPanel {
private GameWindow currentWindow;
public MainPanel () {
currentWindow = new StartWindow(this);
}
public void paintComponent(Graphics g) {
g.drawRect (0, 0, 200, 200); // <-- can see on the window
}
}
abstract class GameWindow {
// contains game loop and update functions and so on
}
class StartWindow extends GameWindow {
MainPanel _parentWindow;
public StartWindow(MainPanel parentWindow) {
super();
_parentWindow = parentWindow;
}
public void paintComponent(Graphics g) {
//Does not work
g.drawRect (20, 20, 100, 100);
}
}
最佳答案
我会在您的主绘图 JComponent 中绘制 Sprite ,例如,
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class MainClass extends JFrame implements ActionListener {
public static void main(String[] args) {
System.out.println("Program Window1");
MainClass glt = new MainClass();
glt.setVisible(true);
}
// ..... other stuff
public MainClass() {
super("Fixed Timestep Game Loop Test");
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
Container cp = getContentPane();
cp.setLayout(new BorderLayout());
JPanel p = new JPanel();
p.setLayout(new GridLayout(1, 2));
System.out.println("Program Window2");
MainPanel gamePanel = new MainPanel();
cp.add(gamePanel, BorderLayout.CENTER);
cp.add(p, BorderLayout.SOUTH);
setSize(500, 500);
}
// .... other stuff
@Override
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
}
}
class MainPanel extends JPanel {
private GameWindow currentWindow;
public MainPanel() {
currentWindow = new StartWindow(this);
}
// public void paintComponent(Graphics g) {
// g.drawRect(0, 0, 200, 200); // <-- can see on the window
// }
// this should be protected, not public and should call super method
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawRect(0, 0, 200, 200); // <-- can see on the window
currentWindow.draw(g);
}
}
interface Drawable {
void draw(Graphics g);
}
abstract class GameWindow implements Drawable {
// contains game loop and update functions and so on
}
class StartWindow extends GameWindow {
MainPanel _parentWindow;
public StartWindow(MainPanel parentWindow) {
super();
_parentWindow = parentWindow;
}
@Override
public void draw(Graphics g) {
g.setColor(Color.red);
g.drawRect(20, 20, 100, 100);
}
}
但我再次重申,游戏循环不应该被继承,而应该传递它的引用。通过组合而不是继承进行扩展。
或者甚至更好,让您的模型类实现一个接口(interface),例如:
public interface Tickable {
void tick(int deltaTime);
}
然后是一个集合,例如 List<Tickable>
由主模型持有,每次游戏循环滴答作响时,它都会遍历列表调用 tick(...)
在列表中的每个项目上。
关于Java 将 JPanel 向下传递给子类,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/32809879/