By Mike Swanson

Unfortunately, the current version of WatchKit doesn't include an activity indicator control (like UIKit's UIActivityIndicatorView), even though the Apple Watch displays an indicator while our interface controllers are loading.

One common approach is to use a WKInterfaceImage object to display an animation while a long-running task is executing. The biggest challenge is finding a series of Apple-like images to animate.

I created JBWatchActivityIndicator to make it easier to configure and generate a series of images.

If you'd just like to grab some Apple-like images, check out the Common Images folder.

Here's an example from the included project that shows some of the attributes that can be interactively modified.

After you've designed a look that you like, tap the Output Image Frames button, and you'll find a series of properly-named PNG images in the document directory (which will be logged during export to make it easy to copy-and-paste the path into the Finder).

To use the exported image sequence, first copy the numbered files to the bundle of your WatchKit app (not your WatchKit extension). I'd highly recommend putting them in an assets library.

Then, to animate the images from your WatchKit extension:

    // Animate a series of images prefixed with the string "Activity"
    [self.interfaceImage setImageNamed:@"Activity"];
    [self.interfaceImage startAnimatingWithImagesInRange:NSMakeRange(0, 15)
                                                duration:1.0
                                             repeatCount:0];

To stop the animation:

	[self.interfaceImage stopAnimating];

That's it.

While this project is primarily intended to create image files that are included in your app bundle, you can alternately use the JBWatchActivityIndicator class to generate image sequences on-the-fly for direct use on the Watch.

Enjoy!