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class ActivityResultManager(private val activityProvider: ActivityProvider) {
private const val SAVED_STATE_REGISTRY_KEY = "permissions_saved_state"
private const val PENDING_RESULT_KEY = "pending"
private const val LAST_INCREMENT_KEY = "key_increment"
private val keyIncrement = AtomicInteger(0)
private var pendingResult: String? = null
suspend fun <I, O, C : ActivityResultContract<I, O>> requestResult(
contract: C,
input: I
): O? {
var (isLaunched, key) = activityProvider.currentActivity?.calculateKey(contract)
?: return null
pendingResult = contract.javaClass.simpleName
return activityProvider.activityFlow
.mapLatest { currentActivity ->
if (!isLaunched) {
currentActivity.prepareSavedData()
}
var launcher: ActivityResultLauncher<I>? = null
try {
suspendCancellableCoroutine<O> { continuation ->
launcher = currentActivity.activityResultRegistry.register(
key,
contract
) { result ->
pendingResult = null
currentActivity.clearSavedStateData()
continuation.resume(result)
}
if (!isLaunched) {
launcher!!.launch(input)
isLaunched = true
}
}
} finally {
launcher?.unregister()
}
}
.first()
}
private fun <C : ActivityResultContract<*, *>> ComponentActivity.calculateKey(contract: C): Pair<Boolean, String> {
fun generateKey(increment: Int) = "result_$increment"
val savedBundle = savedStateRegistry.consumeRestoredStateForKey(SAVED_STATE_REGISTRY_KEY)
return if (contract.javaClass.simpleName == savedBundle?.getString(PENDING_RESULT_KEY)) {
Pair(true, generateKey(savedBundle!!.getInt(LAST_INCREMENT_KEY)))
} else {
Pair(false, generateKey(keyIncrement.getAndIncrement()))
}
}
private fun ComponentActivity.prepareSavedData() {
savedStateRegistry.registerSavedStateProvider(
SAVED_STATE_REGISTRY_KEY
) {
bundleOf(
PENDING_RESULT_KEY to pendingResult,
LAST_INCREMENT_KEY to keyIncrement.get() - 1
)
}
}
private fun ComponentActivity.clearSavedStateData() {
savedStateRegistry.unregisterSavedStateProvider(
SAVED_STATE_REGISTRY_KEY
)
// Delete the data by consuming it
savedStateRegistry.consumeRestoredStateForKey(
SAVED_STATE_REGISTRY_KEY
)
}
}
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