从另一个Objective-C类访问int

Question

I've trying to get an int from another class and it just says that the number is 0 (but it's not).

This is in Class2.h:

@interface Class2 : SKScene <SKPhysicsContactDelegate>{
    Class1 * class;
}

This is in Class2.m:

NSLog(@"%i", class.thisint);

This is in Class1.h:

@property (assign, nonatomic) int thisint;

This is in Class1.m (in viewDidLoad):

thisint = 5;

The NSLog is being called well after the viewDidLoad method but it just keeps saying 0. How do I get this int from Class1? I don't know if the fact that Class2 is an SKScene affects this...

Answer 1

class is an existing method on NSObject and I would hope that you've just used that name for the purposes of this question - if not, please change the name of the variable, it will only lead to confusion.

What do you see if you log class :

NSLog(@"%@",class);

(Put that next to where your existing log is)

How and where are you assigning to the class variable?

A value of 0 probably means one of two things:

• class is nil . This means you haven't assigned it anywhere. You don't magically get a value in a property just because you've declared one

• class is a different instance to the one you think it is. This is a common beginner mistake, where you've done something like

   class = [[Class2 alloc] init]; 

Which creates a new instance. You need to get a reference to the existing instance, which I can't tell you how to do without seeing more code.