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iosobjective-ciboutlet

IBOutlet declaration place

After searching on Google about this confusion, I found out that the best place to put an IBOutlet is:

@interface GallantViewController : UIViewController

@property (nonatomic, weak) IBOutlet UISwitch *switch;

@end

but from what I say, now the switch variable is visible outside of the GallantViewController. Isn't that odd? I thought that this wrong method:

@interface GoofusViewController : UIViewController {
    IBOutlet UISwitch *_switch
}

@end

was behaving like this, and moving it would fix it. Why would you want to manipulate a button for example from another class instead of implementing it's logic just in the GallantViewController?

Solution

  • The @interface can appear in both the .h file (public properties) and the .m file (private properties). The IBOutlets should be declared in the .m file.

    For example, here's a sample .m file for a view controller

    #import "MainViewController.h"

@interface MainViewController ()
// the following property is not visible outside this file
@property (weak, nonatomic) IBOutlet UIView *someView;  
@end

@implementation MainViewController

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

@end

    Technically, the @interface in the .m file is a class extension (also known as an anonymous category on the class), but that's of no practical interest. It's just a way to add private properties to the class.