deprecated-apis

name	deprecated-apis
description	Replacements for deprecated Android APIs — the Activity Result API instead of startActivityForResult/onActivityResult, MenuProvider instead of onCreateOptionsMenu/onOptionsItemSelected, and why a behaviour-locked conversion keeps java.util.Observable rather than silently moving to StateFlow. Use when touching activity results, fragment menus, or observer callbacks.

Retiring Deprecated Android APIs

Never introduce these deprecated APIs in new code, and replace them when you touch code that uses them — a Java→Kotlin conversion is the right moment, since the IDE converter leaves them untouched. Each replacement below is behaviour-preserving. Examples are real conversions from the nextcloud/android client (PRs #16878, #16792), not from this repository.

startActivityForResult / onActivityResult → Activity Result API

The request-code + onActivityResult protocol is deprecated. Register a launcher at construction time and receive the result in its callback.

// BEFORE
startActivityForResult(action, SELECT_LOCATION_REQUEST_CODE)
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
    if (requestCode == SELECT_LOCATION_REQUEST_CODE && data != null) { handle(data) }
}

// AFTER
private val folderPickerLauncher = registerForActivityResult(
    ActivityResultContracts.StartActivityForResult()
) { result ->
    if (result.resultCode == Activity.RESULT_OK) {
        handle(result.data)
    }
}

// launch it:
folderPickerLauncher.launch(intent)

Type-safe, no manual request-code bookkeeping, and it survives process death because registration is declarative. Register during initialization (a field initializer or onCreate/onViewCreated) — never inside a click handler, or the registration is lost.

onCreateOptionsMenu / onOptionsItemSelected → MenuProvider

setHasOptionsMenu(true) plus the two menu overrides are deprecated on Fragment. Add a MenuProvider bound to the view lifecycle instead.

// AFTER
val menuHost: MenuHost = requireActivity()
menuHost.addMenuProvider(object : MenuProvider {
    override fun onCreateMenu(menu: Menu, inflater: MenuInflater) =
        inflater.inflate(R.menu.gallery_menu, menu)

    override fun onMenuItemSelected(item: MenuItem): Boolean = when (item.itemId) {
        R.id.action_select_all -> { selectAll(); true }
        else -> false
    }
}, viewLifecycleOwner, Lifecycle.State.RESUMED)

Passing viewLifecycleOwner + Lifecycle.State.RESUMED auto-adds and removes the menu as the view's lifecycle changes — no leak, no manual setHasOptionsMenu. (PR #16878)

java.util.Observable — Keep or Migrate?

java.util.Observable / Observer are deprecated (Java 9+). But a conversion is behaviour-locked, so do not silently swap the notification mechanism — existing Java observers rely on setChanged() / notifyObservers(). PR #16792 deliberately KEPT it:

class UploadsStorageManager(...) : Observable() {
    fun notifyObserversNow() {
        Handler(Looper.getMainLooper()).post {
            setChanged()
            notifyObservers()
        }
    }
}

Migrating to StateFlow / SharedFlow changes the observation contract and every call site — that is a separate, opt-in refactor, not part of a 1:1 conversion. Note the deprecation, propose the flow migration as a follow-up, and keep the current mechanism unless the developer scopes the larger change.