为什么我的屏幕上没有画任何东西？

Question

我正在使用swing中的2D平台游戏，我正在开发游戏框架。我正在测试reapaint（）并绘制函数，但它们不起作用，而且我很无能。这里是我的代码：

Window.java

import javax.swing.JFrame; 
import javax.swing.SwingUtilities; 

public class Window extends JFrame { 

public Window() { 

    this.setDefaultCloseOperation(EXIT_ON_CLOSE); 
    this.setSize(1000, 1000); 
    this.setVisible(true); 
    this.setTitle("Infiltrator"); 
    this.setLocationRelativeTo(null); 
    this.setContentPane(new Framework()); 
} 

public static void main(String[] args) { 
    SwingUtilities.invokeLater(new Runnable() 
    { 
    @Override 
    public void run() 
    { new Window(); } 
    } 
              ); 

} 





} 

Panel.java

import java.awt.Graphics; 
import java.awt.Graphics2D; 

import javax.swing.JPanel; 

public abstract class Panel extends JPanel { 

public Panel() { 

this.setDoubleBuffered(true); 
this.setFocusable(true); 

/* 
* 
if(false) 
{ 
    BufferedImage blankCursorImg = new BufferedImage(16, 16, BufferedImage.TYPE_INT_ARGB); 
    Cursor blankCursor = Toolkit.getDefaultToolkit().createCustomCursor(blankCursorImg, new Point(0, 0), null); 
    this.setCursor(blankCursor); 
} 
* 
*/ 
} 

public static void Draw(Graphics2D g2d) { 

} 

@Override 
public void paintComponent(Graphics g) 
{ 
Graphics2D g2d = (Graphics2D)g;   
super.paintComponent(g2d);   
Framework.Draw(g2d);  
} 

} 

Framework.java

import java.awt.Color; 
import java.awt.Graphics2D; 

import javax.swing.JFrame; 

public class Framework extends Panel { 

private static long beginTime, takenTime, sleepTime; 
private static long secInNano = 1000000000L; 
private static long secInMilli = 1000000L; 
private static long fps = 60L; 
private static long fpsTime = secInNano/fps; 

public static enum GameState {STARTING, MAINMENU, PLAYING, OVER}; 
public static GameState gameState; 

public Framework() 
{ 
    super(); 

    Thread gameThread = new Thread() { 
     @Override 
     public void run(){ 
      mainLoop(); 
     } 
    }; 

    gameState = GameState.STARTING; 

    gameThread.start(); 
} 

private void mainLoop() { 

    while (gameState != GameState.OVER) { 

     beginTime = System.nanoTime(); 

     switch (gameState) { 
      case STARTING: 
       LoadandInit(); 
       break; 
      case MAINMENU: 
       MainMenu.Update(); 
       break; 
      case PLAYING: 

       break; 
      default: 
       System.out.println("Ok, somebody messed up."); 
       break; 

     } 

     repaint(); 

     takenTime = System.nanoTime() - beginTime; 
     sleepTime = (fpsTime - takenTime)/secInMilli; 
     if (sleepTime < 10) 
      sleepTime = 10; 

     try { 
      Thread.sleep(sleepTime); 
     } catch (InterruptedException ex) { } 


    } 


} 



private static void LoadandInit() { 

    gameState = GameState.MAINMENU; 
} 


public static void Draw(Graphics2D g2d) { 

     g2d.setColor(Color.BLACK); 
     g2d.drawString("DEARP", 0, 0); 
} 

}

Answer 1

要添加框架的一个实例，你的窗口，但框架不覆盖paintCompontents。它有一个由Panel调用的静态Draw方法，但是你永远不会创建面板的实例。

您可以将您的Draw方法转换为paintComponent（），并删除您是Panel类。

此外，您不应该在Framework的构造函数中启动线程。这可能会导致run方法查看成员变量的错误值。创建一个启动线程的新的启动方法。

Answer 2

我会建议的第2章Java中的杀手游戏编程。您可以在本书的网站阅读章节的草案：

http://fivedots.coe.psu.ac.th/~ad/jg/ch1/index.html