CODEWITHSUNDEEP
javastatic
transporter_room_3
transporter_room_3

Reputation: 2633

Static Class Non-Static Member

I'm reading a book on android game development and I've come across the first patch of code:

public static class KeyEvent {
    public static final int KEY_DOWN = 0;
    public static final int KEY_UP = 1;

    public int type;
    public int keyCode;
    public char keyChar;
}

It is my understanding that anything static means there can only be one instance of it.

If there can only ever be one instance of KeyEvent why are type, keyCode and keyChar not declared static as well?

Upvotes: 0

Views: 120

Answers (3)

Joffrey
Joffrey

Reputation: 37660

static does not really mean "there can only be one instance of it".

If you are using the static keyword in any declaration within a class, static means "what I declare here is not a member of an instance of the enclosing class, but it is a member of the class itself."

That being said, if you're declaring a nested class (a class within a class) as static, then it means that the nested class declaration does not rely on an instance of the enclosing class, and can be instantiated directly.

Upvotes: 0

blackpanther
blackpanther

Reputation: 11486

Only nested classes can be declared as static; not outer/normal classes. It allows you to use the static inner class without instantiating the outer class.

Upvotes: 4

Maciej Dobrowolski
Maciej Dobrowolski

Reputation: 12122

Your code is an nested class. static modifier means here that this class is accessible without creating outer class object.

Assuming that outer class is called OuterClass you can call:

KeyEvent ke = new OuterClass.KeyEvent();

Upvotes: 2

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