Java: 使用静态方法在 Main 之外的方法中调用对象

Question

应该很容易解决，但我想知道如何使用在 main 中创建的对象。我试着说 Human h；在 main （或任何其他方法）之外，所以我可以在其他方法中调用它，但是因为我使用的是静态方法，所以我不能使用 h.现在使用此代码，java 告诉我找不到 h（在人工滚动方法中。）

import java.util.Scanner;

class Main
 {
  // static Human h;
  public static void main(String[] args) 
  {
    Scanner scan = new Scanner(System.in);
    Computer c = new Computer();
    Human h = new Human();
    System.out.println("Let's play PIG");
    System.out.println("What is your name");
    String name = scan.nextLine();
    System.out.println("Hello" + " " + name + " " + "you can go first");
    startGame(h, name); 
}
public static void startGame(Human h, String name)
{
Scanner scan = new Scanner(System.in); 
System.out.println("Press r to start your roll");
String rresponse = scan.nextLine();
if(!rresponse.equalsIgnoreCase("R"))
{
System.out.println("Try again");
startGame(h, name);
}
if(rresponse.equalsIgnoreCase("R"))
{
System.out.println("You pressed r, lets roll");
humanRoll(h, name);
}
}
public static void humanRoll(Human h, String name)
{
if(h.getRollNumh()==1)
{
System.out.println(name + " " + "you got a " + h.getRollNumh());
System.out.println("You got a score of" + h.getHumanTurnScore() + "this turn");
System.out.println("Here is your current overall score" + h.getHumanOverallScore());
System.out.println("Your rolled a one, now its the Computers' turn");
switchHuman();
}
}
 }

如果您需要查看 Human class 以提供上下文，我可以快速响应并添加它，但它只是实例变量、默认构造函数、重载构造函数、访问器方法和增变器方法。

Answer 1

如果你希望Human h是静态的（在你的程序中只有一个），那么你可以这样定义它：

static Human h;

public static void main(...) {
...

Answer 2

您可以将 Human 作为方法参数传递给 startGame 和 humanRoll 将它们定义为

public static void startGame(Human human) 
public static void humanRoll(Human human)

然后，在 main 中，调用 startGame(h).

看看这是否有效...

import java.util.Scanner;

class Main {

//tried to put Human h; up here but didn't work due to static methods 

  public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);
    Computer c = new Computer();
    Human h = new Human();
    System.out.println("Let's play PIG");
    System.out.println("What is your name");
    String name = scan.nextLine();
    System.out.println("Hello" + " " + name + " " + "you can go first");
    startGame(h);
  }

  public static void startGame(Human h) {
    Scanner scan = new Scanner(System.in);
    System.out.println("Press r to start your roll");
    String rresponse = scan.nextLine();
    if (!rresponse.equalsIgnoreCase("R")) 
    {
      System.out.println("Try again");
      startGame(h);
    }
    if (rresponse.equalsIgnoreCase("R")) 
    {
      System.out.println("You pressed r, lets roll");
      humanRoll(h);
    }
  }

  public static void humanRoll(Human h) 
  {
//RollNumh is just the dice number that the player rolled 
    if (h.getRollNumh() == 1) 
    {
      System.out.println(name + " " + "you got a " + h.getRollNumh);
      System.out.println("You got a score of" + h.getHumanTurnScore() + "this turn");
      System.out.println("Here is your current overall score" + h.getOverallHumanOverallScore());
      System.out.println("Your rolled a one, now its the Computers' turn");
      switchHuman();
    }
  }

}

Answer 3

在Java中，在函数内部声明的变量只能在函数内部使用。我们说变量的作用域只在函数内。

修复：您可以将变量 h 作为参数传递给其他函数。

Java: 使用静态方法在 Main 之外的方法中调用对象

Java: Calling Object in Method Outside of Main with Static Methods

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