Question

I have a custom class which I want to “load” inside the firstViewController and then access it from other classes by segues. My Problem is, I can’t even access and change the instance variable inside the firstViewController. Somehow I’m “loading” it wrong. Here is the code I used until now:

inside viewController.h

@property (strong, nonatomic) myClass *newClass;

inside viewController.m

@synthesize newClass;

I then try to access it by:

self.newClass.string = @"myString";
if(newClass.string == @"myString"){
  NSLog(@"didn't work");
}

Well, I get “didn’t work”. Why is that?
When I write

myClass *newClass = [myClass new];

It does work. But the class and its properties gets overwritten every time the ViewController loads again.

What would you recommend? Thank you very much.

Answer 1

Like Kaan said, you forgot to initialize your class, You have only declared and created a pointer for it but not the actual object, on your ViewDidLoad add

self.newClass = [[myClass alloc] init];

It does work. But the class and its properties gets overwritten every
time the ViewController loads again.

That’s because every time that specific Viewcontroller loads you are reinitializing the class.

If you want a persistent class through all your program look for the singleton pattern.

This is used in the case when you want to have only 1 instance of a certain object, if you try to initialize another instance of that object you will just receive the one you already have.

PD: newClass.string == @”myString” is wrong.

Use the isEqualToString method when comparing strings.