從其他類訪問數據

Question

我是初學者所以請非常具體。 無論如何，我在這里有三個代碼類，我想從cb然后ba Eg訪問數據

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 ， ViewStats是c

我也不能把它全部放在一個類中，因為最終會有一個修飾符類來編輯CHealth ， MHealth等

Answer 1

在你的班級GoobyPls為每個項目添加getter，如下所示：

class GoobyPls {
{
   private int CHealth = 20;

   public int getHealth(){
      return Chealth;
   }
}

然后在viewStats執行此操作：

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

只要你想使用私有變量，就可以調用getter。 或者您也可以將變量定義為public，以便您可以在viewStats中直接調用它們。 但是作為設計觀點，吸氣劑和制定者更好，因為隱藏信息更好。 除非有充分理由不這樣做，否則應將字段聲明為私有字段。

Answer 2

我強烈建議您閱讀有關類和對象的Java教程 ，這將為您提供良好的工作基礎。

在類之間傳遞數據的最基本方法是在類中定義其他對象可以調用以獲取對數據的訪問權限的公共方法。 例如：

public class Person {

    private String firstName; 
    private String lastName;

    public String getFirstName () {
        return firstName;
    }

    public String getLastName () {
        return lastName;
    }

}

名稱如getX()返回值的方法稱為“getters”。 然后，在另一個類中，您可以訪問該數據，例如：

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

與類通信的另一種方法是編寫帶參數的方法，例如：

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

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

您可能還希望提供在對象中設置數據的方法。 這些被稱為“setter”，是“getters”的對應物。 建立在Person上面：

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;
    }

}

然后，其他對象可以修改人的數據，例如：

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

以下是使用上述所有內容的示例：

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
}

希望有所幫助，祝你好運。 閱讀這些教程！

Answer 3

如果要訪問類外部的私有變量，則必須使用如下所示的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;
}
}  

以下是您的州級課程

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();
}

在您的viewstat類的foo()方法中，您可以通過State.Health ， State.Agility和State.Defence訪問about值。

Answer 4

首先，你不能像你這樣的私人領域

 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而不是字符串

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

使用IDE進行編碼它將幫助您自己識別這類問題。

Answer 5

把getter和setter放到你的班級。或者公開領域。（我不建議第二個）

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;
}  

然后你可以像這樣訪問：

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;
}