Prototyping WatchKit Apps
Rumor has it that the Apple Watch will arrive in March. Exciting as it will be to wrap the final product around your wrist, it’s not too early to start experimenting with WatchKit apps now if you want to know what it’s all about.
Lucky for us developers, people have already posted great ideas on prototyping WatchKit apps without real hardware. For this article, I’d like to summarize what’s currently possible and add a few practical tips of my own.
Xcode Beta with WatchKit
Obviously, the iOS Dev Center should be your first stop in order to download the latest beta version of Xcode 6.2, which includes WatchKit support. There’s a simulator for both the 42mm and 38mm version of the watch and all the tools to code and debug WatchKit apps.
I’ll talk about Xcode and its support for WatchKit apps in future articles. For now, I recommend to read the Apple Watch Programming Guide to get started.
Unfortunately, Xcode’s simulator makes for a crude approximation of the real thing. For one, the simulator approximates the pixel dimensions of the Apple Watch, but not its pixel density (~220 dpi on Retina screens vs 326 dpi for Apple Watch) — thus the screen will be displayed larger than it really is. Also, it’s hard to visualize the watch through the simulator with its functional square window and no borders.
Bezel
At least for the latter problem, Troy Gaul of InfinitApps developed Bezel: a tool to frame the simulator in an Apple Watch-styled window. It even comes with frame images to chose from. (You’d be crazy not to select the Milanese loop.)
The window that Bezel shows is still larger than the actual size of the watch, but looks much closer to the real product. Bezel also makes for a great tool to create screenshots of upcoming Watch apps.
From Bezel, it’s only a small step to use a tool such as xScope or LiveView to mirror the simulated image on to an iPhone’s screen. The advantage being that the iPhone Retina screen has the same pixel density than the Apple Watch. Also, the iPhone is mobile and can be strapped to your wrist to pretend it’s the real watch. Craig Hockenberry describes this technique on his website.
3D Prototyping
If you can’t have the real watch (or a clone), why not 3D print one yourself? Ever since friends of mine opened their 3D printing café “Dimension Alley” in Berlin, I wanted to put this technology to good use. So I asked my friend Norma to print out Michael Christensen’s 3D models for the 38mm and 42mm case.
Having a physical object with the correct size in your hand gives you a much better impression on what it’s like to wear it. Initially, I thought the 42mm case would be too large for my wrist, but now I’m convinced that this is the best size for my arm.
And a final tip if you want to go that route: the wrist straps in the 3D models are very tight, so it will be impossible to actually wear them that way. Instead, I also had a second set printed with the strap cut off so I could place it on top of my arm or use Velcro to wear it.
If you liked this article, you might be interested in my other articles in this series about Practical WatchKit Development:
- Prototyping WatchKit Apps
- Hardware Features of the Apple Watch
- Interacting with WatchKit Apps
- Essential Technologies for Developing WatchKit Apps
If you have any questions about this article, feel free to contact me on Twitter.
