Java 如何更改在不同类中定义的变量

我刚刚开始使用java，我正在创建一个类似于Zork的基于文本的游戏。但是我这里有一些问题

Movement MovementObject = new Movement();

public static void main(String[] args) {

    Room starts;
    starts = new Room();

    starts.Middleroom();


}
public void Middleroom() {
    MovementObject.PlayerSetUp();
    location = "Middleroom"; //here is the problem that i am having it says "location cannot be resolved to a variable"  
    System.out.println("\n\n                   Middleroom ");
    System.out.println("-------------------------------------------------");
    System.out.println("You are in Middleroom to the left there is a very dirty couch.");

}
public void Kitchen() {

    System.out.println("                   \nKitchen\n");
    System.out.println("-----------------------------------------------------\n");
    System.out.println("To the right there is a long staircase that goes to the top floor.\nTo the left there is a kitchen counter.");

这是我的第一节课，第二节课是

Scanner myScanner;
String choice;
Room RoomObject = new Room();
String location = null;



public void PlayerSetUp (){
myScanner = new Scanner(System.in);

//here i am making the movement
if(location.equals("Middleroom")) {
    choice = myScanner.nextLine().toLowerCase();
    switch(choice) {
        case"north":
            RoomObject.Kitchen();
            break;
        case"west":
            RoomObject.Familyroom();
            break;
        default:
            System.err.println("\n!!Invalid Input!!\n");
            RoomObject.Middleroom();
            break;     


}
}

if(location.equals("Familyroom")) {
    switch(choice) {

    }
}

---

我遇到的问题是，它不允许我在第一节课中修改位置。我不知道我是否做错了，但任何建议都会有所帮助，谢谢。

必须在类中将位置定义为属性：

public class Room {
    ...
    private String location;
    ...
}

然后可以使用getter和setter将其公开给其他类：

public class Room {
    ...
    public String getLocation() { return this.location; }
    public void setLocation(String location) { this.location = location; }
}

您甚至可以在课堂上使用它（最佳实践）：

---

如果您不打算在getter或setter中进行任何检查，那么最好将其公开，这样可以使代码更干净、更易于使用。使用“public”字段访问成员是经常讨论的编码范例。我更喜欢使用getter/setter，它在我看来更干净，并且对于将来的代码改进更灵活。但是，如果您想比较不同的编码范例，请搜索“干净的java代码”——您将找到关于该主题的不同书籍。

public class Room {
  ...
  public void Middleroom() {
    MovementObject.PlayerSetUp();
    this.location("Middleroom"); //same as this.location = "Middleroom"
    ...
  }
  ...
}