This is a sample project to shown how to use SpriteKit for animations on the Apple Watch. See the full explanation on Medium.
1. Watch Extension: InterfaceController
Create an IBOutlet for the SpriteKit scene. It has to be of type WKInterfaceSKScene.
2. Watch: Assets
Add the different resolutions of the heart image to your Assets folder.
3. Watch Extension: SpriteKit Scene
Add a new SpriteKit scene to the extension target. Add an SKSpriteNode to the scene and set the texture to the heart image.
4. SpriteKit Scene: Animations
For the animation we added scaleTo actions to the sprite node. One for enlarging, one for shrinking, then a pause, with a total duration of 1 second. Then an infinite loop is created from these actions.
5. Watch: Interface.storyboard
Add a SpriteKit scene to the storyboard and connect it to the IBOutlet. Set the scene property to the one you created above. Make sure the isPaused property is not checked, so the animation is started as soon the scene appears on the screen.