Get integer value from another class

Question

I know i have done this before, but I just cant remember how to do it.

I have a integer, that i want to be able to change in another class of mine.

how do i

Answer 1

You create getter and setter methods (or a property with synthesized accessors) in the class with the integer, give the other class a reference to some instance of the first class, and have it use those accessors to get and set the integer.

Answer 2

In your MainViewClass.h, you'll want to add your int as a property of that class.

@property (nonatomic, readwrite) int score;

Then in your MainViewClass.m, you'll want to synthesize the property using:

@synthesize score;

Now since your subclassing MainViewClass in your OtherClass you can access it's properties using some combination of the following.

In your OtherClass.h add

MainViewClass *mainViewClass;

in your OtherClass.m wherever you need access to the score, you should be able to access it as such.

mainViewClass = (MainViewClass *) self.parent;

and then the score using,

mainViewClass.score;

Answer 3

In your example, int score is an instance variable, or ivar for short. It's a piece of data associated with any given instance of MainViewClass. By default, and for good reason, instance variables have @protected visibility, meaning that only MainViewClass and its subclasses can access it.

Now, you made OtherClass a subclass of MainViewClass in your example, which means to access score from the same object you need only type score or self->score, and from another object that is a MainViewClass you need only type theOtherObject->score. (This sort of design exposes implementation details and so is often considered to be bad design by many coders, but for a simple use case like this you can probably get away with it. Why it's bad is a discussion that has raged for decades and is beyond the scope of this question.)