構造函數創建多個變量，如何通過其他方法返回它們？

Question

public class Game { 

    public Game(
     boolean createstage, //For sorting purposes 
     int slength, 
     int sheight, 
     boolean createplayer, 
     int plength, 
     int pheight, 
     boolean playersprite, 
     BufferedImage psprite, 
     boolean defaultcontrols, 
     String pcontrols, 
     boolean test 
     ) { 
    if(test == true) { //if test is true, test 
     new Test(); 
    }else{ //otherwise create a stage is createstage is true and 
     if(createstage == true) { 
      StageObj gamestage = new StageObj(slength, sheight); 
     } 
     if(createplayer==true) { 
      PlayerObj player = new PlayerObj(plength, pheight, psprite, pcontrols); 
     } 
    } 
} 

public Game() { 
    new StageObj(100, 100); 
    new PlayerObj(10, 10); 
} 

public StageObj givestageobj() { 
    return gamestage; 
} 

public PlayerObj giveplayerobj() { 
    return player; 
} 

} 

因此，我的構造函數的代碼和兩個變量旨在返回在構造函數中創建的變量。問題是，giveplayerobj和givestageobj這兩個方法都沒有找到變量gamestage和player。這是有道理的，但我如何在構造函數中創建變量，然後以某種方式將它們傳遞給giveplayerobj（）和givestageobj（）變量，以便理論上可以有人從Game.giveplayerobj（）返回構造函數中創建的playerobj？

感謝

-JXP

Answer 1

您需要將它們聲明爲類屬性，而不是在構造函數內部工作。所以，你的代碼應該看起來像下面顯示的那樣。

變化：

1. 我已經添加了兩個類變量StageObj andPlayerObj，因爲你必須爲他們的getter到位。
2. 從構造函數中刪除了這兩個變量的聲明。

3. 爲已分配的默認構造函數添加了賦值。 （也許你正試圖實現與默認的構造函數）

   public class Game { 
   
   private StageObj gamestage = null; 
   private PlayerObj player = null; 
   
   public Game(
       boolean createstage, //For sorting purposes 
       int slength, 
       int sheight, 
       boolean createplayer, 
       int plength, 
       int pheight, 
       boolean playersprite, 
       BufferedImage psprite, 
       boolean defaultcontrols, 
       String pcontrols, 
       boolean test 
       ) { 
   if(test == true) { //if test is true, test 
       new Test(); 
   }else{ //otherwise create a stage is createstage is true and 
       if(createstage == true) { 
        gamestage = new StageObj(slength, sheight); 
       } 
       if(createplayer==true) { 
        player = new PlayerObj(plength, pheight, psprite, pcontrols); 
       } 
   } 
   } 
   
   public Game() { 
       gamestage = new StageObj(100, 100); 
       player = new PlayerObj(10, 10); 
   } 
   
   public StageObj givestageobj() { 
       return gamestage; 
   } 
   
   public PlayerObj giveplayerobj() { 
       return player; 
   } 
   
   } 
   

Answer 2

兩個變量gamestage和player必須實例變量：

public class Game { 
    private StageObj gamestage; 
    private PlayerObj player; 

(...) - and in the constructor : 

     if(createstage == true) { 
      gamestage = new StageObj(slength, sheight); 
     } 
     if(createplayer==true) { 
      player = new PlayerObj(plength, pheight, psprite, pcontrols); 
     } 

(...) 

} 

Answer 3

我想你想要的是一個實例變量，即

public class Game { 
    private StageObj gamestage; 
    ... 
    public Game(...) { ... }  

    public StageObj givestageobj() { 
    return gamestage; 
    } 
} 

Answer 4

您需要在co之前設置您的數據字段nstructor做出的getter EN setter方法是這樣的：

public class Game { 

private StageObj gamestage = null; 
private PlayerObj player = null; 

public Game(
    boolean createstage, //For sorting purposes 
    int slength, 
    int sheight, 
    boolean createplayer, 
    int plength, 
    int pheight, 
    boolean playersprite, 
    BufferedImage psprite, 
    boolean defaultcontrols, 
    String pcontrols, 
    boolean test 
    ) { 
if(test == true) { //if test is true, test 
    new Test(); 
}else{ //otherwise create a stage is createstage is true and 
    if(createstage == true) { 
     gamestage = new StageObj(slength, sheight); 
    } 
    if(createplayer==true) { 
     player = new PlayerObj(plength, pheight, psprite, pcontrols); 
    } 
} 
} 

public Game() { 
    gamestage = new StageObj(100, 100); 
    player = new PlayerObj(10, 10); 
} 

public StageObj givestageobj() { 
    return gamestage; 
} 

public PlayerObj giveplayerobj() { 
    return player; 
} 

} 


public Game() { 
new StageObj(100, 100); 
new PlayerObj(10, 10); 
} 

public StageObj givestageobj() { 
return gamestage; 
} 

public PlayerObj giveplayerobj() { 
return player; 
} 

public int getSlenght(){ 
return slenght; 
} 

public void setSlenght(int slenght){ 
this.slenght = slenght; 
} 

} 

等等當然你需要添加其他類，在一個類不能做的一切。您需要播放器和舞臺類;-)另請參見Oracle的Java課程http://docs.oracle.com/javase/tutorial/java/javaOO/