Classes inside of methods...?

[MW130]

Hey guys; I had a general question that I'm not quite getting. In methods, such as the paint method for swing, why are objects declared as parameters? Let me give an example.

public void paint(Graphics g) {}

Why is the Graphics object being declared in parameters? Plus, no instance of it is being created. How does this work?

[Wnt2bsleepin]

You can pass Objects as parameters.

class Person{

     private String name; 
       
     public Person(String name){
         this.name = name; 
      }

     public String getName(){
        return name; 
      }


}

class Test{

     public static void main(String[] args){
          Person me = new Person("sleepin");
          printName(me);
     }

     public static void printName(Person someGuy){
          String name = someGuy.getName();
          System.out.println("My name is " + name);
    }


}

[MW130]

You can pass Objects as parameters.

class Person{

     private String name; 
       
     public Person(String name){
         this.name = name; 
      }

     public String getName(){
        return name; 
      }


}

class Test{

     public static void main(String[] args){
          Person me = new Person("sleepin");
          printName(me);
     }

     public static void printName(Person someGuy){
          String name = someGuy.getName();
          System.out.println("My name is " + name);
    }


}

Ok, but they are not declaring the object of the type Graphics.

[Wnt2bsleepin]

Ok, but they are not declaring the object of the type Graphics.

The method would have to be called with a Graphics object.

[MW130]

The method would have to be called with a Graphics object.

But don't they have to do Graphics g = new Graphics();?

[milovan]

No, they also don't have to do

public static void printName(Person someGuy = new Person()){

don't they?

It is just method signature, you should read about painting components to better understand this.

[MW130]

I think I got it. Thank you very much guys

[Fubarable]

A Graphics object is being created, but not by you. It's being created behind the scenes by the GUI library and then passed into this method when the GUI library calls it. That's one of the reasons why we do "passive" drawing, why we let the GUI library do the drawing itself.