Android Programming: The Big Nerd Ranch Guide, 4th Edition

Challenge: Saving State

Figure out how to persist your boxes across orientation changes from within your View. This can be done with the following View functions:

    protected fun onSaveInstanceState(): Parcelable
    protected fun onRestoreInstanceState(state: Parcelable)

These functions do not work like Activity and Fragment’s onSaveInstanceState(Bundle). First, they will only be called if your View has an ID. Second, instead of taking in a Bundle, they return and process an object that implements the Parcelable interface.

We recommend using a Bundle as the Parcelable instead of implementing a Parcelable class yourself. Kotlin has a @Parcelize annotation that makes it easier to create a Parcelable class, but the Bundle is a commonly ...