how to refresh the viewdidload for parent viewcontroller - ios

Question

I have 2 viewcontrollers with segue "page curl"
viewcontrollerA => pagecurl => viewcontrollerB
and Now I want to update viewcontrollerA since user make some change at viewcontrollerB.
I tryed:
UIStoryboard* sb = [UIStoryboard storyboardWithName:#"mystoryboard"
bundle:nil];
UIViewController* vc = [sb instantiateViewControllerWithIdentifier:#"ExampleViewController"];
[vc ViewDidLoad]; // or ViewWillAppear or ViewDidApear
it works only for the NSLog I put in those functions.
but none of them works with the function which check out Coredata and update the interface.
please help

Answer 1

try this code:
you add parent class
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(actionremovecalender:)
name:#"subMitReport"
object:nil];
-(void)actionremovecalender:(NSNotification *)notification
{
[self ViewDidLoad]
}
call child class
[[NSNotificationCenter defaultCenter]postNotificationName:#"subMitReport" object:nil]

Answer 2

You can send a NSNotification that the parent will receive, or you can set a delegate with a method implemented by the parent view.
In both cases, just reload the view.

Answer 3

In a one-to-one relation, you should prefer the delegation pattern. Just add a weak reference of viewcontrollerA to your viewcontrollerB. You can just call a method (in this case viewDidLoad method) of viewcontrollerA using the reference so you can refresh the views. But I'd prefer declaring a protocol for delegation to prevent tight coupling of two view controllers.

Answer 4

ViewWillApear or ViewDidApear will be called since there is any object changes in the viewcontroller, but if you want to change your viewcontrollerA from another viewcontrollerB, that require NSNotificationCenter to call the function from viewcontrollerA
you can always use NSNotificationCenter to update your parent viewcontroller
At your parent viewcontroller put this:
//since child view controller calls turnItOff, notification center calls function "turnButtonCountinuesOff"
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(turnButtonCountinuesOff) name:#"turnItOff" object:nil];
turnButtonCountinuesOff is your function at parent viewcontroller
At your child viewcontroller put this:
//connect to parent UI view controller calls notification turnItOff.
[[NSNotificationCenter defaultCenter] postNotificationName:#"turnItOff" object:nil];
hope it helps.