Broken Game Loop

我是GUI新手。我不确定如何让我的游戏循环更新，以便userPlayString更新时调用方法determineWinner()。我试图让一个声明，如果是这样的：Broken Game Loop

if (game.userPlayString != null) { 
    game.determineWinner(); 
}

我认为应该执行，但没有happens.This是我到目前为止的代码。谢谢您的帮助。

import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.util.Random; 

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


public class RPSSL implements ActionListener{ 
    public String userPlayString; 
    public String computerPlayString; 

    public int c; 
    public int p; 

    public JButton rockButton = new JButton("Rock"); 
    public JButton paperButton = new JButton("Paper"); 
    public JButton scissorsButton = new JButton("Scissors"); 
    public JButton spockButton = new JButton("Spock"); 
    public JButton lizardButton = new JButton("Lizard"); 

    public JPanel panel = new JPanel(); 

public RPSSL() { 
    userPlayString = null; 
    computerPlayString = null; 
    c = 0; 
    p = 0; 
} 

public void actionPerformed(ActionEvent e) { 
    Object src = e.getSource(); 

    if (src == rockButton) { 
     userPlayString = "Rock"; 
     p = 1; 
    } 
    else if (src == paperButton) { 
     userPlayString = "Paper"; 
     p = 1; 
    } 
    else if (src == scissorsButton) { 
     userPlayString = "Scissors"; 
     p = 1; 
    } 
    else if (src == spockButton) { 
     userPlayString = "Spock"; 
     p = 1; 
    } 
    else if (src == lizardButton) { 
     userPlayString = "Lizard"; 
     p = 1; 
    } 

} 

public void createJFrame() { 
    JFrame frame = new JFrame("Rock Paper Scissors Spock Lizard"); 
    panel.setLayout(null); 

    panel.add(rockButton); 
    rockButton.setBounds(0, 0, 100, 30); 
    rockButton.addActionListener(this); 

    panel.add(paperButton); 
    paperButton.setBounds(0,30,100,30); 
    paperButton.addActionListener(this); 

    panel.add(scissorsButton); 
    scissorsButton.setBounds(0,60,100,30); 
    scissorsButton.addActionListener(this); 

    panel.add(spockButton); 
    spockButton.setBounds(0,90,100,30); 
    spockButton.addActionListener(this); 

    panel.add(lizardButton); 
    lizardButton.setBounds(0,120,100,30); 
    lizardButton.addActionListener(this); 



    frame.add(panel); 
    frame.setVisible(true); 
    frame.setSize(30,200); 
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
} 

public void computerPlay() { 

    Random randomGenerator = new Random(); 
    int computerPlay = randomGenerator.nextInt(5); 
    if (computerPlay == 0){ 
     computerPlayString = "Rock"; 
    } 
    else if (computerPlay == 1) { 
     computerPlayString = "Paper"; 
    } 
    else if (computerPlay == 2) { 
     computerPlayString = "Scissors"; 
    } 
    else if (computerPlay == 3) { 
     computerPlayString = "Spock"; 
    } 
    else if (computerPlay == 4) { 
     computerPlayString = "Lizard"; 
    } 

    System.out.println("Computer played: " +computerPlayString); 

} 

public void humanWins() { 
    System.out.print("You win!"); 
} 

public void computerWins() { 
    System.out.print("You lose!"); 
} 

public void tie() { 
    System.out.print("It's a tie!"); 
} 

public void determineWinner() { 
    //Determines who wins 
    if (userPlayString.equalsIgnoreCase("rock")) { 
     if (computerPlayString.equalsIgnoreCase("rock")) tie(); 
     else if (computerPlayString.equalsIgnoreCase("scissors")) humanWins(); 
     else if (computerPlayString.equalsIgnoreCase("paper")) computerWins(); 
     else if (computerPlayString.equalsIgnoreCase("spock")) humanWins(); 
     else if (computerPlayString.equalsIgnoreCase("lizard")) computerWins(); 
    } 

    else if (userPlayString.equalsIgnoreCase("paper")) { 
     if (computerPlayString.equalsIgnoreCase("rock")) humanWins(); 
     else if (computerPlayString.equalsIgnoreCase("scissors")) computerWins(); 
     else if (computerPlayString.equalsIgnoreCase("paper"))tie(); 
     else if (computerPlayString.equalsIgnoreCase("spock")) humanWins(); 
     else if (computerPlayString.equalsIgnoreCase("lizard")) computerWins(); 
    } 

    else if (userPlayString.equalsIgnoreCase("scissors")) { 
     if (computerPlayString.equalsIgnoreCase("rock")) computerWins(); 
     else if (computerPlayString.equalsIgnoreCase("scissors")) tie(); 
     else if (computerPlayString.equalsIgnoreCase("paper")) humanWins(); 
     else if (computerPlayString.equalsIgnoreCase("spock")) computerWins(); 
     else if (computerPlayString.equalsIgnoreCase("lizard")) humanWins(); 
    } 

    else if (userPlayString.equalsIgnoreCase("spock")) { 
     if (computerPlayString.equalsIgnoreCase("rock")) computerWins(); 
     else if (computerPlayString.equalsIgnoreCase("scissors")) humanWins(); 
     else if (computerPlayString.equalsIgnoreCase("paper")) computerWins(); 
     else if (computerPlayString.equalsIgnoreCase("spock")) tie(); 
     else if (computerPlayString.equalsIgnoreCase("lizard")) humanWins(); 
    } 

    else if (userPlayString.equalsIgnoreCase("lizard")) { 
     if (computerPlayString.equalsIgnoreCase("rock")) humanWins(); 
     else if (computerPlayString.equalsIgnoreCase("scissors")) computerWins(); 
     else if (computerPlayString.equalsIgnoreCase("paper")) humanWins(); 
     else if (computerPlayString.equalsIgnoreCase("spock")) computerWins(); 
     else if (computerPlayString.equalsIgnoreCase("lizard")) tie(); 
    } 
} 
public static void main(String[] args) { 
    RPSSL game = new RPSSL(); 
    game.createJFrame(); 
    while(game.c < 1){ 
     if (game.userPlayString != null) { 
      game.determineWinner(); 
     } 
    } 
} 

}

错误：

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException 
at main.RPSSL.determineWinner(RPSSL.java:126) 
at main.RPSSL.actionPerformed(RPSSL.java:34) 
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022) 
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2346) 
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402) 
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259) 
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252) 
at java.awt.Component.processMouseEvent(Component.java:6525) 
at javax.swing.JComponent.processMouseEvent(JComponent.java:3321) 
at java.awt.Component.processEvent(Component.java:6290) 
at java.awt.Container.processEvent(Container.java:2234) 
at java.awt.Component.dispatchEventImpl(Component.java:4881) 
at java.awt.Container.dispatchEventImpl(Container.java:2292) 
at java.awt.Component.dispatchEvent(Component.java:4703) 
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4898) 
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4533) 
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4462) 
at java.awt.Container.dispatchEventImpl(Container.java:2278) 
at java.awt.Window.dispatchEventImpl(Window.java:2739) 
at java.awt.Component.dispatchEvent(Component.java:4703) 
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:746) 
at java.awt.EventQueue.access$400(EventQueue.java:97) 
at java.awt.EventQueue$3.run(EventQueue.java:697) 
at java.awt.EventQueue$3.run(EventQueue.java:691) 
at java.security.AccessController.doPrivileged(Native Method) 
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75) 
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:86) 
at java.awt.EventQueue$4.run(EventQueue.java:719) 
at java.awt.EventQueue$4.run(EventQueue.java:717) 
at java.security.AccessController.doPrivileged(Native Method) 
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75) 
at java.awt.EventQueue.dispatchEvent(EventQueue.java:716) 
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201) 
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116) 
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105) 
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101) 
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93) 
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

来源

2016-03-03 Simon Lynch

Lynch先生 - 什么是错误？ –

没有错误，只是我的代码没有正确输出到控制台。 :( –

我会想象它循环狂放作为'userPlayString'将永远为空 –

我做你的代码进行一些更改。在determineWinner（）函数中，我添加了对computerPlay（）函数的调用。以前，computerPlay（）函数从未被调用过。我还在if语句中增加了一个game.c变量，以防止无限循环。此外，为了防止CPU过度使用，我已经同步了主方法，抛出了InterruptedException，并在while循环的每次迭代中实现了一个小暂停。如果不这样做，我无法做到这一点。该程序确实调用了determineWinner（）函数，允许用户玩游戏。

将您的代码与本工作示例进行比较。

import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.util.Random; 

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

public class RPSSL implements ActionListener 
{ 
    public String userPlayString; 
    public String computerPlayString; 

    public int c; 
    public int p; 

    public JButton rockButton = new JButton("Rock"); 
    public JButton paperButton = new JButton("Paper"); 
    public JButton scissorsButton = new JButton("Scissors"); 
    public JButton spockButton = new JButton("Spock"); 
    public JButton lizardButton = new JButton("Lizard"); 

    public JPanel panel = new JPanel(); 

    public static synchronized void main(String[] args) throws InterruptedException 
    { 
    RPSSL game = new RPSSL(); 
    game.createJFrame(); 
    while(game.c < 1) 
    { 
     Thread.sleep(10); 
     if (game.userPlayString != null) 
     { 
     game.determineWinner(); 
     game.c++; 
     } 
    } 
    } 

    public RPSSL() 
    { 
    userPlayString = null; 
    computerPlayString = null; 
    c = 0; 
    p = 0; 
    } 

    public void actionPerformed(ActionEvent e) 
    { 
    Object src = e.getSource(); 

    if (src == rockButton) 
    { 
     userPlayString = "Rock"; 
     p = 1; 
    } 
    else if (src == paperButton) 
    { 
     userPlayString = "Paper"; 
     p = 1; 
    } 
    else if (src == scissorsButton) 
    { 
     userPlayString = "Scissors"; 
     p = 1; 
    } 
    else if (src == spockButton) 
    { 
     userPlayString = "Spock"; 
     p = 1; 
    } 
    else if (src == lizardButton) 
    { 
     userPlayString = "Lizard"; 
     p = 1; 
    } 
    } 

    public void createJFrame() 
    { 
    JFrame frame = new JFrame("Rock Paper Scissors Spock Lizard"); 
    panel.setLayout(null); 

    panel.add(rockButton); 
    rockButton.setBounds(0, 0, 100, 30); 
    rockButton.addActionListener(this); 

    panel.add(paperButton); 
    paperButton.setBounds(0,30,100,30); 
    paperButton.addActionListener(this); 

    panel.add(scissorsButton); 
    scissorsButton.setBounds(0,60,100,30); 
    scissorsButton.addActionListener(this); 

    panel.add(spockButton); 
    spockButton.setBounds(0,90,100,30); 
    spockButton.addActionListener(this); 

    panel.add(lizardButton); 
    lizardButton.setBounds(0,120,100,30); 
    lizardButton.addActionListener(this); 



    frame.add(panel); 
    frame.setVisible(true); 
    frame.setSize(30,200); 
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    } 

    public void computerPlay() 
    { 
    Random randomGenerator = new Random(); 
    int computerPlay = randomGenerator.nextInt(5); 
    if (computerPlay == 0) 
    { 
     computerPlayString = "Rock"; 
    } 
    else if (computerPlay == 1) 
    { 
     computerPlayString = "Paper"; 
    } 
    else if (computerPlay == 2) 
    { 
     computerPlayString = "Scissors"; 
    } 
    else if (computerPlay == 3) 
    { 
     computerPlayString = "Spock"; 
    } 
    else if (computerPlay == 4) 
    { 
     computerPlayString = "Lizard"; 
    } 

    System.out.println("Computer played: " + computerPlayString); 

    } 

    public void humanWins() 
    { 
    System.out.print("You win!"); 
    } 

    public void computerWins() 
    { 
    System.out.print("You lose!"); 
    } 

    public void tie() 
    { 
    System.out.print("It's a tie!"); 
    } 

    public void determineWinner() 
    { 
    computerPlay(); 
    //Determines who wins 
    if (userPlayString.equalsIgnoreCase("rock")) 
    { 
     if (computerPlayString.equalsIgnoreCase("rock")) tie(); 
     else if (computerPlayString.equalsIgnoreCase("scissors")) humanWins(); 
     else if (computerPlayString.equalsIgnoreCase("paper")) computerWins(); 
     else if (computerPlayString.equalsIgnoreCase("spock")) humanWins(); 
     else if (computerPlayString.equalsIgnoreCase("lizard")) computerWins(); 
    } 

    else if (userPlayString.equalsIgnoreCase("paper")) 
    { 
     if (computerPlayString.equalsIgnoreCase("rock")) humanWins(); 
     else if (computerPlayString.equalsIgnoreCase("scissors")) computerWins(); 
     else if (computerPlayString.equalsIgnoreCase("paper"))tie(); 
     else if (computerPlayString.equalsIgnoreCase("spock")) humanWins(); 
     else if (computerPlayString.equalsIgnoreCase("lizard")) computerWins(); 
    } 

    else if (userPlayString.equalsIgnoreCase("scissors")) 
    { 
     if (computerPlayString.equalsIgnoreCase("rock")) computerWins(); 
     else if (computerPlayString.equalsIgnoreCase("scissors")) tie(); 
     else if (computerPlayString.equalsIgnoreCase("paper")) humanWins(); 
     else if (computerPlayString.equalsIgnoreCase("spock")) computerWins(); 
     else if (computerPlayString.equalsIgnoreCase("lizard")) humanWins(); 
    } 

    else if (userPlayString.equalsIgnoreCase("spock")) 
    { 
     if (computerPlayString.equalsIgnoreCase("rock")) computerWins(); 
     else if (computerPlayString.equalsIgnoreCase("scissors")) humanWins(); 
     else if (computerPlayString.equalsIgnoreCase("paper")) computerWins(); 
     else if (computerPlayString.equalsIgnoreCase("spock")) tie(); 
     else if (computerPlayString.equalsIgnoreCase("lizard")) humanWins(); 
    } 

    else if (userPlayString.equalsIgnoreCase("lizard")) 
    { 
     if (computerPlayString.equalsIgnoreCase("rock")) humanWins(); 
     else if (computerPlayString.equalsIgnoreCase("scissors")) computerWins(); 
     else if (computerPlayString.equalsIgnoreCase("paper")) humanWins(); 
     else if (computerPlayString.equalsIgnoreCase("spock")) computerWins(); 
     else if (computerPlayString.equalsIgnoreCase("lizard")) tie(); 
    } 
    } 
}

来源

2016-03-03 05:30:03

当做这样一个循环时，被中断的异常和thread.sleep是必要的，还是仅仅习惯于减少CPU使用率 –

睡眠对于您的程序正常执行是必需的，否则您的循环会迭代得太快并占用所有CPU的时间。尝试在没有睡觉的情况下运行程序，您会看到。当我创建一个游戏循环时，我通常会制定一个系统来强制循环每秒重复特定的次数。这不是通过像这样简单地睡觉线来完成的;线程将要休眠的时间量取决于底层系统。 –

如果你喜欢我的回答，你会介意给它一个投票吗？我需要投票才能解锁教师徽章！ –

Broken Game Loop

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