How #available works in Swift

This article from the Big Nerd Ranch blog goes back to 2016, but it’s a great little rundown by Mark Dalrymple of #available, introduced back in Swift 2.0.

Hi! I’m #available!

Sometimes we just use language features like this and don’t really think about what’s going on under the hood when we use them, or perhaps we have a mental model based on past assumptions. However, Mark does a an excellent job filling in some of the details on this handy feature of Swift, explaining not only what it is but also what it is not.

The article also clarifies Xcode’s Target SDK version and Deployment Target version, which can initially be a point of confusion to many developers on the iOS platform.

Here’s a great summary of the article from the article itself (a TLDR;):

The take-away points: #available is not #if—it is not conditional compilation based on OS platform. Instead, at compile time, #available tells the compiler to temporarily raise the SDK level above your deployment target so that you can safely use newer API. At run time, the code will execute depending on the version of the OS the app is running on.

Handy Swift Resource: Hacking With Swift’s Auto Layout Cheat Sheet

This is a pretty great one-stop-shopping resource for Auto Layout by Paul Hudson.

The Auto Layout cheat sheet – Hacking with Swift

Auto Layout is a powerful tool for creating flexible, maintainable rules for your user interface. It can also be a real brain vortex if you’re unlucky – it’s something that makes hard things easy and easy things hard.

To help relieve the pain, in this article I’ve put together code snippets to solve a variety of common Auto Layout problems: creating constraints, animating constraints, adjusting constraints at runtime, and more.

As with all of Paul’s articles, it’s well thought out, and it’s a useful resource to stash away for the next time you need to do in-code work with Auto Layout and Swift.

It is disappointing that he does not use the word “vexing” anywhere this blog post as I had thoroughly expected him to do (and would have been so appropriate in any article about Auto Layout), but the tips are so good, I’ll overlook it this time.

Excellent resource.

When Worlds Collide: How to call complex Objective-C selectors from Swift

When developing in Swift, you will eventually need to interact with Objective-C APIs. Most of the time this is fine, and fairly straightforward to do using #selector.

However, every once in a while you will need to invoke an Objective-C selector that you did not write (usually when the selector is part of the iOS or macOS SDK), does not have a unique signature, or is just pretty hard to figure out.

This article put out by Big Nerd Ranch’s Mark Dalrymple is an excellent rundown of how to properly invoke Objective-C selectors from Swift. He even covers really hairy signatures that may be very difficult to come up with on your own at first glance.

Big Nerd Ranch — Hannibal #selector

The selector is key to Objective-C’s dynamic runtime nature. It’s just a name that’s used, at runtime, as a key into a dictionary of function pointers. Whenever you send a message to an Objective-C object, you’re actually using a selector to look up a function to call. Sometimes selectors bubble up in Cocoa/CocoaTouch API, and you will need to deal with them in Swift.

iOS Dev Break Episode 009: It Was A Very Googly Experience

The latest episode of iOS Dev Break has arrived! This one was recorded just before WWDC, and a new episode will be published shortly!

It Was A Very Googly Experience – IDB009 | iOS Dev Break

In this episode: The return of iOS Dev Break! Adventures with the Google Play Store, Swift 4 and the Codeable protocol, plus AirPods and their amazing user experience!

Google Chrome Pro Tip: How to Merge Multiple Tabs from Two Google Chrome Windows

I have been wanting the ability to merge two window’s collections of tabs in Google Chrome for some time now, because moving one tab a time from one window to another is tedious at best.

I thought I’d need an extension for it, but it turns out that you can already do it in Chrome without any extra extension! I found this tip on the Google Chrome Product Forums, which tells how to do it:

Merge two windows with multiple tabs

Left-click the first tab in the window you want to merge. While holding the shift key, left-click the right most tab. All of tabs for the current window are now selected, so you can drag and drop them as as group on the other window.

One thing the tip doesn’t mention is that you have to keep holding down the Shift key while doing this process to move all tabs, otherwise it shifts back into single-tab-move-mode.

Hope this helps!

Video: Forward Swift 2016 – “How Hot Is My Coffee? Sensors, Core Bluetooth and Swift!”

Somehow I don’t think I broadcasted this when it was available so now seems a good a time as any…

My Core Bluetooth talk from Forward Swift 2016, “How Hot Is My Coffee? Sensors, Core Bluetooth and Swift!” has been up since last year, but thankfully it’s still up!

Evan K. Stone: How Hot Is My Coffee? Sensors, Core Bluetooth and Swift! – Forward Swift 2016

Fitbit, Withings, Nest. The Internet of Things (IoT) innovation tidal wave has just begun, and those are just three of the more well-known players in the IoT and connected gadget landscape. It’s critical that iOS developers know how to connect and interact with BLE prototyping devices using the Core Bluetooth Framework provided by the iOS SDK. In this session, you’ll get the jump-start you need to begin creating engaging apps that bring these devices to life.

Big thanks to the awesome folks at Forward Swift!

Video: Forward Swift 2017 – “What’s this React Native Thing I Keep Hearing About?”

Here’s the video for the talk on React Native I did for Forward Swift in March of 2017 in San Francisco! I’m very glad I didn’t have to wait until November for this one – the Forward Swift team has done an amazing job of getting out their videos in record time!

Evan K. Stone: What’s This React Native Thing I Keep Hearing About?

In our daily lives as iOS developers, we can usually happily keep coding away in Swift and ignore what’s going on in other software development communities, like that of JavaScript. However, there may be some advantages to at least becoming familiar with what’s going on in the world of React Native, and in this session you will get an overview of what React Native is, and why it could be a useful addition to your toolbox an iOS developer.

Video: AltConf 2016 – “Saving Lives with iBeacons”

Evidently this got posted to Realm’s website back in November, and I was not informed. Better late than never!

Evan K. Stone – Saving Lives with iBeacons

You’ve probably heard of iBeacons, but have you seen them up close or developed apps for them? iBeacon technology is a fun and easy way to start working with Bluetooth Low Energy devices. Cloud City Development has been working with Pop Up Labs at MIT to help develop a solution for educating health professionals about the Maker Movement and how it positively affects the medical community. With the help of iBeacons, health professionals have learned how to start creating their own devices and tools!

In this talk from AltConf 2016, Evan will introduce you to iBeacons, show you examples of how to interact with them in an iOS app, and demonstrate how iBeacons were implemented in a Medical Maker Kit. By helping medical staff learn about the items in the kit, they are able to get creative, build new projects, and ultimately save lives! This talk will give you a glimpse of what can be accomplished with iBeacons and will encourage you to think of new ways in which Bluetooth Low Energy devices like iBeacons can be used to design and develop creative solutions that enhance the experience of life!

React Navigation: a Collaborative Effort in the React Native Community

React Navigation for React Native is “collaboration between people from Facebook, Exponent and the React community at large” as this comment on the project’s GitHub page indicates:

React Navigation is born from the React Native community’s need for an extensible yet easy-to-use navigation solution. It replaces and improves upon several navigation libraries in the ecosystem, including Ex-Navigation, React Native’s Navigator and NavigationExperimental components. React Navigation can also be used across React and React Native projects allowing for a higher degree of shared code. Once stable, NavigationExperimental will be deprecated in favor of React Navigation. React Navigation is a collaboration between people from Facebook, Exponent and the React community at large.

Also interesting is the revealing that React Native’s NavigationExperimental will be deprecated in favor of this new navigation system.

Details can be found here: