Wrap up

Multipeer connectivity is something that used to be awfully hard, but in iOS it's less than 150 lines of code to produce this entire app – and over half of that is code for the collection view and the image picker!

The advantage it has compared to traditional data sharing over Wi-Fi is that multipeer can use an existing Wi-Fi network, or can silently create a new Wi-Fi network or even a Bluetooth network depending on what's available. All this is an implementation detail that Apple solves on your behalf – we don’t have to care how it works.

Review what you learned

Anyone can sit through a tutorial, but it takes actual work to remember what was taught. It’s my job to make sure you take as much from these tutorials as possible, so I’ve prepared a short review to help you check your learning.

Click here to review what you learned in project 25.

Challenge

One of the best ways to learn is to write your own code as often as possible, so here are three ways you should try your new knowledge to make sure you fully understand what’s going on:

Show an alert when a user has disconnected from our multipeer network. Something like “Paul’s iPhone has disconnected” is enough.
Try sending text messages across the network. You can create a Data from a string using Data(yourString.utf8), and convert a Data back to a string by using String(decoding: yourData, as: UTF8.self).
Add a button that shows an alert controller listing the names of all devices currently connected to the session – use the connectedPeers property of your session to find that information.

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Share your success!

One of the most effective motivators of success is sharing your progress with other people – when you tell folks what you're doing and what you've learned, it encourages you to come back for more, which in turn will help you reach your app development goals faster.

So, now that you've done all the hard work it's time to share your success: tell folks that you've completed this project, either by clicking the button below to start composing a tweet, or by writing your own message from scratch. This will definitely encourage you to keep learning, but it will also help other folks discover my work – thank you!