iOS equivalent of launching an Activity in Android

Question

I just got done writing an Android Activity that allows other Activities to call it for some result (it's not intended to be a stand-alone Activity). I'm now working on the equivalent iOS application and can't find any resources for how I would enable similar functionality on iOS.

The situation: The tool I'm producing is intended to be used by other applications, rather than as a standalone application. The thing is, the GUI that needs to be presented to the user is rather involved so I'd like to be able to provide the developer with a "all-in-one" package that they can simply launch and get results from. Doing this in Android was very straight forward. I simply wrote an Activity and instructed the developer to launch this Activity for result. I've looked around and can't find a similar functionality to allow an iOS developer to do the same. What would be the best way to go about doing this?

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I think part of the problem I'm having in finding resources is that I'm not entirely sure what what I'm making is called. A library? extension? plug-in? I would think a library doesn't have a GUI and it seems extensions and plug-ins are made for an extensible application (that is, one in which the user can install the extension/plug-in).

Answer 1

Your API could be à single call that would pop up a modal view. A target and selector can be specified to receive an answer. Supplying it to other developers means packing it into a "framework". I'm not sure if you can include resources.

Answer 2

There isn't really any equivalent. The closest you can come is having the second application call UIApplication's openURL with a custom scheme that is listened to by your app, and then when your app is done it would do the same with a custom scheme that is listened to by the calling app.

In practice, the iOS app would usually include the entire activity-equivalent as some sort of library, which at the high level would take the form of a UIViewController subclass that is presented modally and then calls a delegate method or completion selector of some sort on completion.