📊 Capítulo 17: WorkManager & Background Tasks

Especialização em Mobile Nativo Android

🗺️ A Garantia de Execução com Android Jetpack WorkManager

flowchart TD
    APP["App agenda tarefa com Constraints (ex: Bateria > 20% & Conectado no Wi-Fi)"]
    --> WM["WorkManager Engine (Persiste no SQLite interno do Android)"]
    WM --> CHECK{"Condições do SO atendidas?"}
    CHECK -- "SIM" --> EXEC["Executa CoroutineWorker.doWork() mesmo se o app for FECHADO pelo usuário!"]
    CHECK -- "NÃO" --> WAIT["Aguardar até o smartphone conectar ao Wi-Fi ou carregar"]
    EXEC --> RETRY{"Houve Falha de Rede?"}
    RETRY -- "SIM" --> BACKOFF["Result.retry() com Exponential Backoff"]
    RETRY -- "NÃO" --> SUCCESS["Result.success()"]

    style APP fill:#ede7f6,stroke:#512da8,stroke-width:2px
    style WM fill:#fff3e0,stroke:#ff9800,stroke-width:2px
    style CHECK fill:#e1f5fe,stroke:#03a9f4,stroke-width:1.5px
    style EXEC fill:#e8f5e9,stroke:#4caf50,stroke-width:2px
    style WAIT fill:#ffebee,stroke:#d32f2f,stroke-width:1.5px
    style RETRY fill:#fff3e0,stroke:#ff9800,stroke-width:1.5px
    style BACKOFF fill:#fff9c4,stroke:#fbc02d,stroke-width:1.5px
    style SUCCESS fill:#c8e6c9,stroke:#2e7d32,stroke-width:2px

🎯 Slide 1: Implementando um `CoroutineWorker`

class SincronizacaoWorker(
    context: Context,
    params: WorkerParameters,
    private val repository: TransacaoRepository
) : CoroutineWorker(context, params) {

    override suspend fun doWork(): Result {
        return try {
            repository.sincronizarComServidor()
            Result.success()
        } catch (e: Exception) {
            Result.retry()
        }
    }
}

🎯 Slide 2: Definindo Constraints Rígidas

val constraints = Constraints.Builder()
    .setRequiredNetworkType(NetworkType.UNMETERED) // Somente Wi-Fi
    .setRequiresBatteryNotLow(true)
    .build()

val syncRequest = PeriodicWorkRequestBuilder<SincronizacaoWorker>(6, TimeUnit.HOURS)
    .setConstraints(constraints)
    .build()

🎯 Slide 3: Execução Imediata com Expedited Work

Para uploads prioritários enquanto o app vai para o background, utilize setExpedited(OutOfQuotaPolicy.RUN_AS_NON_EXPEDITED_WORK_REQUEST) com notificações em primeiro plano (Foreground Service).