How do you share data between view controllers and other objects in Swift?

Question

Say I have multiple view controllers in my Swift app and I want to be able to pass data between them. If I\'m several levels down in a view controller stack, how do I pass d

Answer 1

As @nhgrif pointed out in his excellent answer, there are lots of different ways that VCs (view controllers) and other objects can communicate with each other.

The data singleton I outlined in my first answer is really more about sharing and saving global state than about communicating directly.

nhrif's answer lets you send information directly from the source to the destination VC. As I mentioned in reply, it's also possible to send messages back from the destination to the source.

In fact, you can set up an active one-way or 2-way channel between different view controllers. If the view controllers are linked via a storyboard segue, the time to set up the links is in the prepareFor Segue method.

I have a sample project on Github that uses a parent view controller to host 2 different table views as children. The child view controllers are linked using embed segues, and the parent view controller wires up 2-way links with each view controller in the prepareForSegue method.

You can find that project on github (link). I wrote it in Objective-C, however, and haven't converted it to Swift, so if you're not comfortable in Objective-C it might be a little hard to follow