Question

I have a viewController I’ve built in storyboard. I also have a NSObject Subclass which acts as my model, which sends and listens for API requests and responses. When a method fires in my model, I want to present a modal View of my viewController from whatever view happens to be visible at the time.

An example would be if my API hears “show this view” I want to show viewController regardless of what view is being shown.

Conceptually, how does one do this?

EDIT: I don’t know which view controller will be showing when I want to present my modal viewController. Also, I need to pass params from my model to the modalVC when it’s presented.

Answer 1

I would send a notification from the model telling “someone” that some view needs be displayed.

NSDictionary *userInfo = @{ @"TheViewKey": viewToDisplay];
[[NSNoticationCenter defaultCenter] postNotificationName:@"NotificationThatThisViewNeedsToBeDisplayed" object:self userInfo:userInfo];

And then on the delegate (or the active view controller) would register to this notification and handle the display.

// self is the delegate and/or the view controller that will receive the notification
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleViewToDisplay:) name:@"NotificationThatThisViewNeedsToBeDisplayed" object:nil];

If you put in the view controller remember to remove self from the observers when the view is not visible:

[[NSNotificationCenter defaultCenter] removeObserver:self name:@"NotificationThatThisViewNeedsToBeDisplayed"];

This way your model is decoupled from the presentation.