Mobile Connectivity & Background Execution.

Background work and connectivity on iOS and Android: Doze, WorkManager, BGTaskScheduler, background modes, reachability and constrained sync. Covers 6 sub-skills.

• Mobile Connectivity & Background Execution · 1 of 3

  WorkManager (Constraints, Expedited, Periodic)

  In a chained set of one-time work where B depends on A, A has not finished yet. Which WorkInfo state describes B while it waits for A?

  AWAITINGBPENDINGCBLOCKEDDDEFERRED

• Mobile Connectivity & Background Execution · 2 of 3

  WorkManager (Constraints, Expedited, Periodic)

  In chain A -> B -> C, worker B returns Result.failure() with no successful retry. What happens to C?

  AC is moved to FAILED and never executesBC retries on B's behalf using B's configured backoff policyCC runs anyway, since each link's result is independentDC is skipped cleanly and the chain reports overall SUCCEEDED

• Mobile Connectivity & Background Execution · 3 of 3

  WorkManager (Constraints, Expedited, Periodic)

  Unique work named 'sync' has already ended badly: its last run gave up for good. A request is enqueued onto that name with ExistingWorkPolicy.APPEND. What happens to the request you just enqueued?

  AIt stays BLOCKED forever waiting for the failed head to recoverBIt throws at enqueue because you cannot append onto failed workCIt runs normally because APPEND starts a fresh chainDIt inherits the FAILED state immediately and never runs