Delegate is being released in case of custom View created with XIB - ios

Question

I have created MyCustomView.xib/h/m: which extends UIView class. Then in my Main.storyboard, put UIView object, changed the class to MyCustomView and linked to MainController.h. So, MainController contains reference to MyCustomView instance.
For loading from xib, in MyCustomView I do the following:
- (instancetype)initWithCoder:(NSCoder *)aDecoder
{
self = [super initWithCoder:aDecoder];
if (self) {
if (self.subviews.count == 0) {
[self commonInit];
}
}
return self;
}
- (instancetype)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
[self commonInit];
}
return self;
}
- (void) stretchToSuperView:(UIView*)view
{
view.translatesAutoresizingMaskIntoConstraints = NO;
NSDictionary *bindings = NSDictionaryOfVariableBindings(view);
NSString *formatTemplate = #"%#:|[view]|";
for (NSString * axis in #[#"H",#"V"]) {
NSString * format = [NSString stringWithFormat:formatTemplate,axis];
NSArray * constraints = [NSLayoutConstraint constraintsWithVisualFormat:format options:0 metrics:nil views:bindings];
[view.superview addConstraints:constraints];
}
}
- (void)commonInit
{
MyCustomView* view = nil;
NSArray *views = [[NSBundle mainBundle] loadNibNamed:#"MyCustomView" owner:self options:nil];
view = views.firstObject;
[self addSubview:view];
[self stretchToSuperView:views.firstObject];
}
This works quite well, until I want to declare delegate in MyCustomView in order to notify MainController to any change(button click, etc). So, my ManController conforms MyCustomViewDelegate and implements methods.
EDIT 1 setting delegate
//MainViewController.m file
#interface MainViewController ()
#property (strong, nonatomic) IBOutlet MyCustomView *customView;
#end
#implementation MainViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.customView.delegate = self;
}
The problem here is that delegate becomes nil and I don't understand the reason, so don't know what's the mistake.
Edit 2 I think somehow I have 2 different instances of MyCustomView.
I have added new property in MyCustomView:
#interface MyCustomView : UIView
#property (weak, nonatomic) IBOutlet UIButton *firstItem;
#property(nonatomic, weak)id <MyCustomViewDelegate> delegate;
// this is test property
#property(nonatomic, assign)int testProperty;
#end
And when I set this property in viewDidLoad and then click to first button, I see that testProperty has value 0. So, this could mean something wrong with IBOutlet MyCustomView *customView.

Answer 1

You are correct, that you have two view objects. The one that you added to the storyboard and the one you created via loadNibNamed.
Bottom line, loadNibNamed will create the view for you (assuming that you've specified MyCustomView as the base class for the view specified in the NIB; you can leave NIB's "File owner" blank). You can then write a convenience method in MyCustomView to instantiate the NIB-based view:
+ (instancetype)myCustomViewWithDelegate:(id<MyCustomViewDelegate>)delegate {
NSArray *array = [[NSBundle mainBundle] loadNibNamed:#"MyCustomView" owner:delegate options:nil];
MyCustomView *view = array.firstObject;
NSAssert([view isKindOfClass:[MyCustomView class]], #"Base class of NIB's top level view is not MyCustomView");
view.delegate = delegate;
return view;
}
Then, rather than specifying the view on the storyboard, you must instantiate and add it to the view hierarchy programmatically, e.g.:
- (void)viewDidLoad {
[super viewDidLoad];
MyCustomView *view = [MyCustomView myCustomViewWithDelegate:self]; // since `self.myCustomView` should be `weak`, let's hold the view in local variable
[self.view addSubview:view];
self.myCustomView = view; // then set the property after the view is safely added to view hierarchy
NSDictionary *views = #{#"myCustomView" : self.myCustomView};
self.myCustomView.translatesAutoresizingMaskIntoConstraints = false;
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"H:|[myCustomView]|" options:0 metrics:nil views:views]];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"V:|[myCustomView]|" options:0 metrics:nil views:views]];
// ...
}
Obviously, when adding a view programmatically, you have to specify its frame and autoresizingMask, or use constraints like shown above.

Answer 2

Unfortunately, I can't make a simple comment, so I have to ask, and give advices as 'answer'.
First of all, I don't see where do you set the delegate to your MainController, but I think in the viewDidLoad() of the controller.
Second thing. It's really important how do you setup your MyCustomView.xib, because you create a brand new object MyCustomView, and its properties will be unavailable from the controller.
MyCustomView* view = nil;
NSArray *views = [[NSBundle mainBundle] loadNibNamed:#"MyCustomView" owner:self options:nil];
view = views.firstObject;
[self addSubview:view];
Without knowing the setup of the xib, and setting method of the delegate, here is my guess what could help you:
In MyCustomView.xib set the class of the rootView to UIView.
In MyCustomView.xib set the class of the File's Owner to MyCustomView
Create your subview as a UIView.
UIView* view = nil;
NSArray *views = [[NSBundle mainBundle] loadNibNamed:#"MyCustomView" owner:self options:nil];
view = views.firstObject;
[self addSubview:view];
Set the delegate of the myCustomView object in your controller.
self.myCustomView.delegate = self;
I hope it will help, if not, then please extend your question with the delegate setter code block, and your xib setup method. (class of file's owner, class of root view etc)