Set Bool in custom property from view controller

Question

Allocating a custom class in a vc. Then I set a bool value (either set or . notation). The value never gets to the custom class - always reports NO.

Googled and tried many different variations - none work. What else could be wrong with the code below?

CustomView.h

    @interface CustomView : UIScrollView <UIScrollViewDelegate> {
    BOOL myLocalProperty;
}

@property (assign) BOOL myProperty;

CustomView.m

     @implementation CustomView

    @synthesize myProperty =_myProperty;

    - (id)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];

    myLocalProperty = _myProperty;

    if (myLocalProperty==YES) {
        NSLog(@"YES");
    } else if (myLocalProperty==NO) {
        NSLog(@"NO");
    }

    return self;
}

ViewController.m (in some method that is def. being called)

CustomView *myView = [[CustomView alloc] initWithFrame:CGRectZero];

    myView.myProperty=YES;

This value of YES never gets to the property. Anything obviously wrong here?

score 3 · Accepted Answer · answered Sep 04 '13 at 22:27

The value of YES does get there, but that happens after you have printed the default NO.

The current value of _myProperty is printed in the initializer; by the time you assign the property YES, the initializer is done!

You can check that the value does get there by adding a method to show the current value of the property:

- (id)showMyProperty {
    myLocalProperty = _myProperty;
    if (myLocalProperty==YES) {
        NSLog(@"YES");
    } else if (myLocalProperty==NO) {
        NSLog(@"NO");
    }
}

Now change your code that creates CustomView as follows:

CustomView *myView = [[CustomView alloc] initWithFrame:CGRectZero];
myView.myProperty=YES;
[myView showMyProperty]; // This should produce a "YES" in NSLog

score 1 · Answer 2 · answered Sep 04 '13 at 22:27

You're logging the value of myProperty in CustomView's initWithFrame: method, but you're not assigning YES to myProperty until initWithFrame: has returned. You should try logging NSLog("myView.myProperty = %@", myView.myProperty ? @"YES" : @"NO"); after your assignment, myView.myProperty = YES;.

Set Bool in custom property from view controller

2 Answers2