How can I access another View Controller's variables without creating a new instance of it?

Question

I've been recently trying to migrate my app into an MVC format and I was wondering how one would go about accessing a View Controller's variables (trying to access them FROM a .swift file) without having to create a new instance of the View Controller. For example:

HomePageViewController().objectIDs.append(post.objectId!)


HomePageViewController().postTitles.append(post["Title"] as! String)


HomePageViewController().imageFiles.append(post["imageFile"] as! PFFile)


HomePageViewController().descriptions.append(post["description"] as! String)


HomePageViewController().userNames.append(post["originalPosterUserName"] as! String)


HomePageViewController().numOfComments.append(String(describing: post["numberOfComments"]!))


print(HomePageViewController().userNames, "This is a test")

The print statement at the end prints '[]This is a test' with no data inside of the array. Inside of the HomePageViewController file, this works perfectly though. I'm assuming that this isn't working due to me creating a new instance of the HomePageViewController and altering THOSE variables rather than the current one. So, my question is, how would I be able to alter the variables of the current HomePageViewController without the need to create a new instance?

A solution like this wouldn't work either since I have multiple classes with the same variable names.

I'd appreciate any help. Thanks!

View controllers are not supposed to access data from anywhere other than a model. — Sergey Kalinichenko
– Sergey Kalinichenko, Commented Mar 14, 2017 at 22:23

jglasse · Accepted Answer · 2017-03-14 22:27:23Z

2

If you're implementing MVC, the data you wish to be share across multiple view controllers should be contained in the model, and either instantiated as a singleton and accessed globally (as with UserDefaults) or passed from one controller to the other as a parameter when you present the new VC.

By definition, View Controllers should not be accessing each others' variables.

answered Mar 14, 2017 at 22:27

jglasse

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3 Comments

Gabe Over a year ago

Ok, makes sense. So, the variables should reside in the model class and I should access them from the View Controller file in order to update/manage the UI?

jglasse Over a year ago

That's correct. You can access them explicitly in code, or using KVO. Hope my answer helped.

Gabe Over a year ago

Yep, that cleared it up for me. Thanks for the help!

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