调用在另一个类中创建的对象的方法

Question

I have a little problem.

I have a 3 classes looks "like" this:

public class Gun{
    public void Shot(){
        // shoot code
    }

    public void RenderGun()
    {
        // render code
    }

    // more methods
}


public class GameManager
{
    Gun gun;

    public GameManager()
    {
        gun = new Gun();
    }

    // methods using GunClass methods.
}

public class HudScreen
{
    Gun gun;

    public HudScreen()
    {
        gun = new Gun();
    }

    public void GunShotButton()
    {
        gun.Shoot();
    }
}

The problem is I have two Gun objects and i want to have one but use it in both classes HudScreen and GameManager.

So, if I create a new Gun object in GameManager, how to "call" this object from the HudScreen class?

---

Thanks, MM.

Answer 1

Change constructors in that way:

public GameManager(Gun gun) {
   this.gun = gun;
}

and the same in HudScreen class. Then in some Main class:

class Main {    
   public static void main(String[] args) {
      Gun gun = new Gun();
      HudScreen hudScreen = new HudScreen(gun);
      GameManager gameManager = new GameManager(gun)
   }
}

Currently main method is assumed to be the top level method doing the initilization. This may be some other method as well where objects of Gun , GunManager and HudScreen are created.

Answer 2

GameManager constructor

 public GameManager(Gun gun){ 
     this.gun = gun;
 }

HudScreen constructor

public HudScreen(Gun gun){
      this.gun = gun;
 }

From the main method where you create the Gun object you can pass it to the constructors of GameManager and HudScreen

 public static void main() {
      Gun gun = new Gun();
      HudScreen hudScreen = new HudScreen(gun);
      GameManager gameManager = new GameManager(gun)
   }

If you do not want to create GameManager and HudScreen in same method but still want to use same Gun object then you can do it this way 1. Initialize Gun object 2. on the GameManager and Hudscreen you can either pass it on constructor or you can directly pass it to method in theses classes. eg Assume you want to keep the GameManager constructor receive the newly created Gun and pass the same gun to Hudscreen.GunShotButton. I hope you got a clue here -

public class Gun{
    public void Shot(){
        // shoot code
    }

    public void RenderGun()
    {
        // render code
    }

    // more methods
}


public class GameManager
{
    Gun gun;

    public GameManager(Gun gun)
    {
        this.gun =gun;
    }

    // methods using GunClass methods.
}

public class HudScreen
{   
    public HudScreen()
    {
    }

    public void GunShotButton(Gun gun)
    {
        gun.Shoot();
    }
}

Answer 3

register a ScreenController to every NiftyGUI screen. create a ScreenController by creating a Java class that implements the de.lessvoid.nifty.screen.ScreenController interface and its abstract methods.