Publishers and operators are pointless unless something is listening to the published events. Like a river, values come from the upstream publisher and flow to the downstream publisher.
Macbook swift publisher series#
Think of values flowing from the original publisher, through a series of operators. You can chain multiple operators together to perform complex processing. An operator describes a behavior for changing values, adding values, removing values or many other operations. Operators are special methods that are called on publishers and return the same or a different publisher. Several Foundation types have been enhanced to expose their functionality through publishers, including Timer and URLSession, which you’ll use in this tutorial. A failure with an error of Failuretype.The protocol has two associated types: Output, the type of value it produces, and Failure, the type of error it could encounter.Įvery publisher can emit multiple events: Objects that conform to Publisher deliver a sequence of values over time. Taking each component in turn: Publishers Subscribers: Things that care about values.Operators: Things that do work with values.Publishers: Things that produce values.The Combine framework provides a declarative API to process values over time. Can you work out what’s happening, and in what order? What if you wanted to change the order things happen in, or bail out, or add new functionality? Time to get some help from Combine! Introduction to Combine Right now, this is a fully working game, but take a look at playGame() in GameViewController.swift.
You’ll also see a button for starting or stopping the game: The main screen shows you four gray squares. Open UnsplashAPI.swift and add your Unsplash API key to UnsplashAPI.accessToken like this:īuild and run. Our game is fun, but please avoid playing it too much :] Note: Unsplash APIs have a rate limit of 50 calls per hour. Once complete, you’ll see a screen like this: After registration, you’ll need to create an app on their developer’s portal. Open the starter project and check out the project files.īefore you can play the game, you must register at Unsplash Developers Portal to get an API key.
Macbook swift publisher download#
Ready to explore the magic world of Combine in iOS? Time to dive in! Getting Startedĭownload the project materials using the Download Materials button at the top or bottom of this tutorial. You’ll see these key concepts in action by enhancing FindOrLose, a game that challenges you to quickly identify the one image that’s different from the other three.
Macbook swift publisher code#
You can use Combine to unify and simplify your code for dealing with things like delegates, notifications, timers, completion blocks and callbacks. Combine, announced at WWDC 2019, is Apple’s new “reactive” framework for handling events over time.
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