Question

I have Class1, Class2, and SubclassOfClass2. I want to call method that is in SubclassOfClass2 from Class1. I do:

Class2 *class = [[Class2 alloc] init];
[class someMethod];

But, as I guess, due to alloc, all variables values are being lost after that. Because:

At runtime Class2 is being executed. It sets for example variable float x = image.size.width. And it returns correct value. Later, after for example user pressed button, Class1 is being executed. After calling someMethod from Class1 variable x returns 0.00000. How to make it working so that variables values wouldn’t be lost?

As I have been asked, here is my someMethod code:

-(void)someMethod {
NSLog(@"%f", x);
}

At run time that method returns 3200.00000 and when its called from Class1 it returns 0.00000. Variable x is declared in Class2 and method someMethod is in SubclassOfClass2

---

Class1.h

@interface Class1

@end

Class1.m

#import "Class1.h"
#import "Class2.h"

@implementation Class1
-(IBAction)buttonPressed:(id)sender {
Class2 *class = [[Class2 alloc] init];
[class someMethod];
}
@end

Class2.h

@interface Class2 {
 float x;
}
@end

Class2.m

#import "Class2.h"
#import "SubclassOfClass2.h"

@implementation Class2
- (id)initWithCoder:(NSCoder *)coder {
    x = 3200;
    [self someMethod];
    return self;
}
@end

SubclassOfClass2.h

#import "Class2.h"

@interface Class2 (subclass) {
}
-(void)someMethod;
@end

SubclassOfClass2.m

#import "SubclassOfClass2.h"
@implementation Class2 (subclass)
 -(void)someMethod {
   NSLog(@"%f", x);
 }
@end

Answer 1

It returns 0.00000 because you’re calling init. That’s a different method from initWithCoder:, which is the one that sets x.

(Other problems: have your classes inherit from NSObject as a base class and don’t use class as a variable name…especially when it’s not a class object.)