Objective-c get base class property from subclass

Question

I created in .h file @property (for example BOOL value). In .m file i change BOOL value.

In subclass code i want to get value of this property NSLog(@"%@", _value) , but value is always null.

Base class code:

.h file:

@interface CommonViewController : UIViewController <MPPGraphDelegate, MPPInputSourceDelegate>

...

@property(nonatomic) BOOL buttonState;

@property(nonatomic) UIButton* button;

...

@end

.mm file:

- (void)viewDidLoad {
  [super viewDidLoad];
   ...

    _button = [UIButton buttonWithType:UIButtonTypeCustom];
    [_button addTarget:self
                       action:@selector(aMethod:)
                       forControlEvents:UIControlEventTouchUpInside];
    [_button setTitle:@"Show View" forState:UIControlStateNormal];
    _button.frame = CGRectMake(100, 500, 120, 30);
    [self.view addSubview:_button];
}

-(void)aMethod:(UIButton*) sender {
    if (sender.isSelected) {
        sender.selected = NO;
        _buttonState = NO;  <-- change value
    } else {
        sender.selected = YES;
        _buttonState = YES;  <-- change value
    }
}

Subclass code

.h file:

@interface HandTrackingViewController : CommonViewController
...
@end

.mm file:

@implementation HandTrackingViewController

@synthesize buttonState = _buttonState;
- (void)someMethod {
      NSLog(_buttonState ? @"YES" : @"NO"); <-- _buttonState always null
}

@end

Can you show more code? How can you get value from the subclass? — son, Jan 12 '21 at 04:15
Does this answer your question? [Why can't I use the property of a superclass in a subclass (Objective-C)](https://stackoverflow.com/questions/26551722/why-cant-i-use-the-property-of-a-superclass-in-a-subclass-objective-c) — Willeke, Jan 12 '21 at 07:20
Or this [Can't inherit public property from parent class in child class](https://stackoverflow.com/questions/25875116/obj-c-cant-inherit-public-property-from-parent-class-in-child-class) — Willeke, Jan 12 '21 at 07:21
Adding ```@synthesize``` doesn't help because the property is always null. Removing ```@synthesize``` doesn't help because of undeclared identifier — capybar133213, Jan 12 '21 at 07:48

score 0 · Answer 1 · answered Jan 12 '21 at 07:58

0

self.buttonState without @synthesize solved my problem

answered Jan 12 '21 at 07:58

capybar133213

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Objective-c get base class property from subclass

1 Answers1