What is the lifecycle of Watch App?

Question

There are two subclasses of WKInterfaceController in my Apple Watch app. The first one is the entrance of another one, their relationships is nextPage with the Interface Builder. For the awakeWithContext, willActivate and didDeactivate method in each InterfaceController, I printed them all out while watch app launching.

And I got this output:

awakeWithcontext -> First
awakeWithContext －> Second
willActivate －> First
willActivate -> Second
didDeactivate －> Second

and I swipe to the next InterfaceController:

willActivate -> Second
didDeactivate －> First

So now the question is:

Will all the awakeWithContext method of all InterfaceControllers in Watch App be fired as long as launched?

What about the willActivate method?

Answer 1

The life cycle of watchOS apps is as described below.

awakeWithContext

When initializing the page, awakeWithContext will be called. This is the first method to be called, and no UI is displayed yet.

You should do something like updating model arrays for table views, setting properties, etc in awakeWithContext. This method has a very similar job to initializers in simple classes (init()), but this time in WKInterfaceControllers.

The answer of your first question:

awakeWithContext will be called on ALL PAGES as soon as the watchOS app launches.

willActivate

When the interface controller is about to be displayed, willActivate will be called.

You should update label values, actions and anything else related to view elements there.

The answer of your second question:

willActivate will be called on ALL PAGES as soon as the watchOS app launches, but in contrast with awakeWithContext, this will be called again as soon as you view the controller (in other words, when you navigate to that desired interface).

For the first time you launch the app, all controllers' didDeactivate will be called, except the current, and when going to another, its willActivate will be called prior to didDeactivate being called on first one.

So the life cycle is:

1- awakeWithContext of all views

2- willActivate of all views

3- didDeactivate of all views, except the first one (the current one)

And when swiping to the second:

1- willActivate of the second view

2- didDeactivate of the first view