indexoutofboundsexception IndexOutOfBoundsError在用Java编写游戏时出错

1 年，2 月 Questions & Answers 127

我在编写一个学校项目的代码时遇到了IndexOutOfBound错误。此问题不稳定，此问题似乎是随机发生的

public void run(){ // Main game methode 
    Image Background = this.images.get(0);//get background because we can
    Player Player1 = this.players.get(0);//get player 1
    Player Player2 = this.players.get(1);//get player 2

    Player1.setHorSp(1);//give start speed to player 1
    Player2.setHorSp(1);//give start speed to player 2
    while(this.running == true && this.crash == false){ // main game loop, loops when game is started and there is no crash
        // Player 1
        if(this.turnable == 0 && Player1.getDir() > 0){
            Player1.setPrevLine(Player1.getCurrentLine());//safe previous line for testing
            if(Player1.getDir() == 1){ //check which key and horizontal speed so it can't move in opposite direction
                if(Player1.getHorSp() == -1){
                    Player1.setLineX(Player1.getX()+grid/2); //set end of line
                    Player1.setLineY(Player1.getY()+grid/2);
                    addLine(Player1.getLineX(),Player1.getLineY(),Player1.getLineX(),Player1.getLineY(),Color.BLUE);//make next line
                    Player1.setCurrentLine(Player1.getLineNr()+Player2.getLineNr());//use next line
                    Player1.setX(Player1.getX());
                    Player1.setY(Player1.getY()-Player1.getWidth()+Player1.getHeight());
                }
                if(Player1.getHorSp() == 1){
                    Player1.setLineX(Player1.getX()+Player1.getWidth()-grid/2); //set end of line
                    Player1.setLineY(Player1.getY()+grid/2);
                    addLine(Player1.getLineX(),Player1.getLineY(),Player1.getLineX(),Player1.getLineY(),Color.BLUE);//make next line
                    Player1.setCurrentLine(Player1.getLineNr()+Player2.getLineNr());//use next line
                    Player1.setX(Player1.getX()-Player1.getHeight()+Player1.getWidth());
                    Player1.setY(Player1.getY()+Player1.getHeight()-Player1.getWidth());
                }
                Player1.setLineNr(Player1.getLineNr()+1); //tell player that it had turned
                Player1.setImage("BikeBlueUp.png"); //change image in the right direction
                Player1.setWidth(grid); //correct images size
                Player1.setHeight(2*grid);
                Player1.setLineX(Player1.getX()+grid/2);//set point line is atteched to bibe
                Player1.setLineY(Player1.getY()+grid/2);
                Player1.setHorSp(0); //give speed in the right direction
                Player1.setVerSp(-1);
            }
            if(Player1.getDir() == 2){ //check which key and if is in grid
                if(Player1.getVerSp() == -1){
                    Player1.setLineX(Player1.getX()+grid/2); //set end of line
                    Player1.setLineY(Player1.getY()+grid/2);
                    addLine(Player1.getLineX(),Player1.getLineY(),Player1.getLineX(),Player1.getLineY(),Color.BLUE);//make next line
                    Player1.setCurrentLine(Player1.getLineNr()+Player2.getLineNr());//use next line
                    Player1.setX(Player1.getX());
                    Player1.setY(Player1.getY());
                }
                if(Player1.getVerSp() == 1){
                    Player1.setLineX(Player1.getX()+grid/2); //set end of line
                    Player1.setLineY(Player1.getY()+Player1.getHeight()-grid/2);
                    addLine(Player1.getLineX(),Player1.getLineY(),Player1.getLineX(),Player1.getLineY(),Color.BLUE);//make next line
                    Player1.setCurrentLine(Player1.getLineNr()+Player2.getLineNr());//use next line
                    Player1.setX(Player1.getX());
                    Player1.setY(Player1.getY()+Player1.getHeight()-Player1.getWidth());
                }
                Player1.setLineNr(Player1.getLineNr()+1); //tell player that it had turned
                Player1.setImage("BikeBlueRight.png"); //change image in the right direction
                Player1.setWidth(2*grid); //correct images size
                Player1.setHeight(grid);
                Player1.setLineX(Player1.getX()+Player1.getWidth()-grid/2);//set point line is atteched to bibe
                Player1.setLineY(Player1.getY()+grid/2);
                Player1.setHorSp(1); //give speed in the right direction
                Player1.setVerSp(0);
            }
            if(Player1.getDir() == 3){ //check which key and horizontal speed so it can't move in opposite direction
                if(Player1.getHorSp() == -1){
                    Player1.setLineX(Player1.getX()+grid/2); //set end of line
                    Player1.setLineY(Player1.getY()+grid/2);
                    addLine(Player1.getLineX(),Player1.getLineY(),Player1.getLineX(),Player1.getLineY(),Color.BLUE);//make next line
                    Player1.setCurrentLine(Player1.getLineNr()+Player2.getLineNr());//use next line
                    Player1.setX(Player1.getX());
                    Player1.setY(Player1.getY());
                }
                if(Player1.getHorSp() == 1){
                    Player1.setLineX(Player1.getX()+Player1.getWidth()-grid/2); //set end of line
                    Player1.setLineY(Player1.getY()+grid/2);
                    addLine(Player1.getLineX(),Player1.getLineY(),Player1.getLineX(),Player1.getLineY(),Color.BLUE);//make next line
                    Player1.setCurrentLine(Player1.getLineNr()+Player2.getLineNr());//use next line
                    Player1.setX(Player1.getX()-Player1.getHeight()+Player1.getWidth());
                    Player1.setY(Player1.getY());
                }
                Player1.setLineNr(Player1.getLineNr()+1); //tell player that it had turned
                Player1.setImage("BikeBlueDown.png"); //change image in the right direction
                Player1.setWidth(grid); //correct images size
                Player1.setHeight(2*grid);
                Player1.setLineX(Player1.getX()+grid/2);//set point line is atteched to bibe
                Player1.setLineY(Player1.getY()+Player1.getHeight()-grid/2);
                Player1.setHorSp(0); //give speed in the right direction
                Player1.setVerSp(1);
            }
            if(Player1.getDir() == 4){ //check which key and horizontal speed so it can't move in opposite direction
                if(Player1.getVerSp() == -1){
                    Player1.setLineX(Player1.getX()+grid/2); //set end of line
                    Player1.setLineY(Player1.getY()+grid/2);
                    addLine(Player1.getLineX(),Player1.getLineY(),Player1.getLineX(),Player1.getLineY(),Color.BLUE);//make next line
                    Player1.setCurrentLine(Player1.getLineNr()+Player2.getLineNr());//use next line
                    Player1.setX(Player1.getX()-Player1.getHeight()+Player1.getWidth());
                    Player1.setY(Player1.getY());
                }
                if(Player1.getVerSp() == 1){
                    Player1.setLineX(Player1.getX()+grid/2); //set end of line
                    Player1.setLineY(Player1.getY()+Player1.getHeight()-grid/2);
                    addLine(Player1.getLineX(),Player1.getLineY(),Player1.getLineX(),Player1.getLineY(),Color.BLUE);//make next line
                    Player1.setCurrentLine(Player1.getLineNr()+Player2.getLineNr());//use next line
                    Player1.setX(Player1.getX()-Player1.getHeight()+Player1.getWidth());
                    Player1.setY(Player1.getY()+Player1.getHeight()-Player1.getWidth());
                }
                Player1.setLineNr(Player1.getLineNr()+1); //tell player that it had turned
                Player1.setImage("BikeBlueLeft.png"); //change image in the right direction
                Player1.setWidth(2*grid); //correct images size
                Player1.setHeight(grid);
                Player1.setLineX(Player1.getX()+grid/2);//set point line is atteched to bibe
                Player1.setLineY(Player1.getY()+grid/2);
                Player1.setHorSp(-1); //give speed in the right direction
                Player1.setVerSp(0);
            }
        }

这将生成错误：

Exception in thread "Thread-5" java.lang.IndexOutOfBoundsException: Index: 5, Size: 5
at java.util.ArrayList.RangeCheck(ArrayList.java:547)
at java.util.ArrayList.get(ArrayList.java:322)
at Game.run(Game.java:388)
at java.lang.Thread.run(Thread.java:619)

现在按下up按钮时仍然发生此错误。这一错误在其他2次中都没有发生，然后从现在开始就发生了

此错误是在按下右键后生成的

Exception in thread "Thread-5" java.lang.IndexOutOfBoundsException: Index: 11, Size: 11
at java.util.ArrayList.RangeCheck(ArrayList.java:547)
at java.util.ArrayList.get(ArrayList.java:322)
at Game.run(Game.java:388)
at java.lang.Thread.run(Thread.java:619)

这个错误是在按下右键后产生的，在同一个游戏中，它在之前的1次中有效。。。即使经过3天的调试，我们仍然看不到用户

以前有人见过这种情况吗？如果有，我们如何解决

--JYT

Ps.整个代码在这里http://pastebin.com/0wvyr3qh

共 (1) 个答案

# 1 楼答案
我不确定你想做什么，但发生错误是因为： Player2.getCurrentLine()返回this.lines.size()的值，因此，您尝试访问列表中不存在的对象（如果列表大小为5，则其对象为0-4）

如果网格是循环的，可以使用：
```
Line CurrentLineP2 = this.lines.get(Player2.getCurrentLine() % this.lines.size());
```
而不是：
```
Line CurrentLineP2 = this.lines.get(Player2.getCurrentLine());
```
如果不是循环的，你需要处理这个案子。一个球员怎么可能站在一条不存在的线上

在任何情况下，添加所有相关代码都将有助于我们帮助您

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indexoutofboundsexception IndexOutOfBoundsError在用Java编写游戏时出错

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# 1 楼答案