8 things you should know about developing for the Apple Watch

The Apple Watch does not compute. Literally. That’s not a market assessment, it’s a statement of fact, as explained by Nick Lee, a partner at Tendigi.
Apple’s wearable will let your iPhone crunch its code and simply display what your phone comes up with, which is why some latency is built into the system’s simulator. On the other hand, it makes the battery life much better. Tendigi organizes the Brooklyn iOS Developer Meetup, which met at Huge’s Dumbo space Wednesday for the “Exploring Apple Watch” session.
Lee said that he has already developed some Watch apps for a few Tendigi clients. He demo’d one simple app that he’d made on his own. Lee’s app shows the next arrival times for subways near you in New York City.
Markiyan Matsekh, a project manager for Ukrainian software firm Eleks, also spoke about an Apple Watch app he developed as an experiment, for the Tesla Model S. (That is, Tesla didn’t ask them to make it, but the company has fairly open APIs, so Eleks was able to swing it.)

Here are some insights into developing for the Apple Watch that Lee and Matsekh shared at the meetup:

1. Communication is one way. The watch can ask the phone for data but the phone can’t ask the watch, Lee said.
2. Don’t ask much of UI. Lee said you’ll want to minimize the number of UI update calls, due in large part to latency. Animation is a giant pain on the watch, as both speakers emphasized. Lee said to do them as image sequences, if animation is key.
3. Apple is jealous. The watch has a lot of great interface and sensor features, but, at this point, developers don’t really have access to them.
4. Location is on your phone. To your watch, your location is the last location cached on your phone, so be sure your settings there are such that it will be current.
5. It won’t be sexy. The watch is small and Apple has put so many restrictions on the UI that Eleks designers weren’t able to make their app, in Matsekh’s view, “sexy.” There were too many rules. “It’s kind of a great challenge to build rich experiences,” Matsekh said.
6. Icons. You’ll need two icons for your WatchKit app, one for each size the watch will come in.
7. Updates are on your phone. App updates on your phone will include WatchKit updates, so that if you get a watch they will be ready to use. Your watch won’t ask for the update. Your iPhone will.
8. Digital Crown, the haptic dial and button. While the Apple Watch can sense the force of your touch, which is a powerful feature, it also features a haptic control, in the form of a turnable button on the side. Very nice, but thus far developers don’t have access to it.

Matsekh said they are working on a version of the Tesla app for Android Wear now. Android wearables do their own computations, which is one big difference. You can build a custom watch face on Android and it is more geared to voice control than Apple.
Matsekh, however, likes Pebble best, of the wearables out there, but he doesn’t own any yet. Pebble uses physical buttons for many of its controls (and developers can access them), which he thinks is a better interface for a watch. In Philadelphia, a developer recently made transit schedules Pebble-friendly.