Kotlin and Android Development featuring Jetpack: End Ch. 11 app runs but consistently crashes

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Alright, this took me a bit since my original app still works as written, so I’m thinking this is due to a change in one of the navigation library. It’s seems like it’s trying to be helpful and re-create your Fragment automatically, but since it doesn’t know the leaderType it can’t.

I’d say the proper approach here is to send the leaderType as an argument to the LeadersListFragment rather than as a constructor parameter:

val leaderType = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
    arguments?.getSerializable(LEADER_TYPE_KEY, LeaderType::class.java)
} else {
    arguments?.getSerializable(LEADER_TYPE_KEY) as? LeaderType
} ?: LeaderType.Batting

You can then remove leaderType from the constructor. Note that the extra version check logic is due to arguments?.getSerializable(LEADER_TYPE_KEY) being deprecated for API level 33, but our app supports lower versions.

You can also do this the easy way and make the constructor parameter nullable:

class LeadersListFragment(private val leaderType: LeaderType? = LeaderType.Batting)

Sorry this took a bit for me to get back to you!