從其他類訪問數據

Question

我是一個初學者，所以請非常特別。無論如何，我在這裏有三個代碼類，我想從c-b訪問數據，然後b-a E.g.

class GoobyPls { 
{ 
    private int CHealth = 20; 
    private int MHealth = 20; 
    private int CAgility = 10; 
    private int MAgility = 10; 
    private int CDefence = 5; 
    private int MDefence = 5; 
} 
} 

class Stats { 
public static void foo() { 
    string Health = CHealth + "/" + MHealth ; 
    string Agility = CAgility + "/" + MAgility; 
    string Defence = CDefence + "/" + MDefence; 
} 

} 

class ViewStats { 
public static void foo() { 
System.out.println("Health"); 
       System.out.println(Health); 
       System.out.println(" "); 
       System.out.println("Agility"); 
       System.out.println(Agility); 
       System.out.println(" "); 
       System.out.println("Defence"); 
       System.out.println(Defence); 
       System.out.println(" "); 
    } 
} 

所以GoobyPls是a，Stats是b和ViewStats是c

還我不能把它們都放在一個類，因爲終究會有一個修飾類編輯CHealth，MHealth等

Answer 1

訪問約值在你的類GoobyPls添加干將每個項目如下：

無論何時，當你想使用私有變量

GoodyPls gp = new GoobyPls(); 
System.out.println(gp.getHealth()); 

就叫干將：

，然後在viewStats做到這一點。或者你也可以定義public變量，以便你可以直接在viewStats中調用它們。但是，從設計的角度來看，getter和setter更好，因爲隱藏信息更好。 除非不是這樣做的充分理由，否則字段應聲明爲私人。

Answer 2

把getter和setter放到你的班上，或者讓你的班級公開。（我不建議第二班）

class GoobyPls { 

    public int getCHealth() { 
     return CHealth; 
    } 
    public void setCHealth(int cHealth) { 
     CHealth = cHealth; 
    } 
    public int getMHealth() { 
     return MHealth; 
    } 
    public void setMHealth(int mHealth) { 
     MHealth = mHealth; 
    } 
    public int getCAgility() { 
     return CAgility; 
    } 
    public void setCAgility(int cAgility) { 
     CAgility = cAgility; 
    } 
    public int getMAgility() { 
     return MAgility; 
    } 
    public void setMAgility(int mAgility) { 
     MAgility = mAgility; 
    } 
    public int getCDefence() { 
     return CDefence; 
    } 
    public void setCDefence(int cDefence) { 
     CDefence = cDefence; 
    } 
    public int getMDefence() { 
     return MDefence; 
    } 
    public void setMDefence(int mDefence) { 
     MDefence = mDefence; 
    } 
    private int CHealth = 20; 
    private int MHealth = 20; 
    private int CAgility = 10; 
    private int MAgility = 10; 
    private int CDefence = 5; 
    private int MDefence = 5; 
} 

然後你就可以像這樣訪問：

class Stats { 
public static void foo() { 
GoobyPls gbp=new GoobyPls(); 
    string Health = gbp.getCHealth + "/" + MHealth ; 
    string Agility = gbp.getCAgility + "/" + MAgility; 
    string Defence = gbp.getCDefence + "/" + MDefence; 
} 

Answer 3

我強烈建議通過Java tutorial on classes and objects，它會給你一個良好的基礎工作從閱讀。

在類之間傳遞數據的最基本方法是定義類中的其他對象可以調用以訪問數據的公共方法。例如：

public class Person { 

    private String firstName; 
    private String lastName; 

    public String getFirstName() { 
     return firstName; 
    } 

    public String getLastName() { 
     return lastName; 
    } 

} 

方法與像getX()返回值的名字被稱爲「干將」。然後，在另一個類，您可以訪問數據，例如：

public void elsewhere() { 
    Person p = new Person(); 
    System.out.println(p.getFirstName() + " " + p.getLastName()); 
} 

帶班溝通的另一種方式是寫有參數的方法，例如：

public void printFullName (Person p) { 
    System.out.println(p.getFirstName() + " " + p.getLastName()); 
} 

public void elsewhere() { 
    Person p = new Person(); 
    printFullName(p); 
} 

您可能還需要提供方法設置數據在一個對象中。這些被稱爲「制定者」，是「獲得者」的對應物。從上面建立在Person：

public class Person { 

    private String firstName; 
    private String lastName; 

    public String getFirstName() { 
     return firstName; 
    } 

    public String getLastName() { 
     return lastName; 
    } 

    public void setFirstName (String firstName) { 
     this.firstName = firstName; 
    } 

    public void setLastName (String lastName) { 
     this.lastName = lastName; 
    } 

} 

然後，其他對象可以改變一個人的數據，例如：

public void elsewhere() { 
    Person p = new Person(); 
    p.setFirstName("Bob"); 
    System.out.println(p.getFirstName()); // prints "Bob" 
} 

下面是使用一切從上面的例子：

public void swapPersonFirstAndLastName (Person p) { 
    String temporary = p.getFirstName(); 
    p.setFirstName(p.getLastName()); 
    p.setLastName(temporary); 
} 

public void printFullName (Person p) { 
    System.out.println(p.getFirstName() + " " + p.getLastName()); 
} 

public void example() { 
    Person p = new Person(); 
    p.setFirstName("John"); 
    p.setLastName("Smith"); 
    swapPersonFirstAndLastName(p); 
    printFullName(p); // prints Smith John 
} 

希望幫助還有祝你好運。閱讀這些教程！

Answer 4

你不能，你的私人領域希望首先如下

class GoobyPls { 
{ 
    private int CHealth = 20; // you can't use private here 
    private int MHealth = 20; // and care on java naming conventions 
    private int CAgility = 10; 
    private int MAgility = 10; 
    private int CDefence = 5; 
    private int MDefence = 5; 
} 
} 

，它應該是String不串

string Health = CHealth + "/" + MHealth ; // String not string 

使用IDE做編碼它會幫助你識別那些樣由你自己的問題。

Answer 5

如果你想訪問類之外的私有變量，你必須使用下面的getter方法。

class GoobyPls { 
private int CHealth = 20; 
private int MHealth = 20; 
private int CAgility = 10; 
private int MAgility = 10; 
private int CDefence = 5; 
private int MDefence = 5; 
public int getCHealth() { 
    return CHealth; 
} 
public int getMHealth() { 
    return MHealth; 
} 
public int getCAgility() { 
    return CAgility; 
} 
public int getMAgility() { 
    return MAgility; 
} 
public int getCDefence() { 
    return CDefence; 
} 
public int getMDefence() { 
    return MDefence; 
} 
} 

下面是你的狀態類

class Stats { 
public static void foo() { 
GoobyPls g=new GoobyPls(); 
int Health = g.getCHealth()/g.getMHealth() ; 
int Agility = g.getCAgility()/g.getMAgility(); 
int Defence = g.getCDefence()/g.getMDefence(); 
} 

，並在您viewstat類的foo()方法，你可以通過State.Health，State.Agility和State.Defence