Background Tasks in Flutter

This codelab builds a production-grade background job layer for Flutter that respects how mobile platforms schedule work and conserve power. You will set up a top-level callback that runs in a background isolate, register it early in app startup, and carefully pass small inputs that the worker can act on without relying on UI. On Android you will configure WorkManager with clear constraints for network, charging, and idle, enqueue unique work to prevent duplicates, and add backoff so transient failures back off rather than hammer the server. You will tag jobs to inspect or cancel them and persist results to local storage so the foreground UI can render progress and history. You will validate execution across app states by killing the app, rebooting the device, and observing that constrained jobs run once the device meets your conditions. On iOS you will register BGTaskScheduler identifiers, request background refresh appropriately, and adapt expectations to the cooperative model where the system grants limited time windows. Throughout, you will make tasks idempotent, avoid large payloads by chunking or using resumable uploads, and guard with connectivity checks so retries only happen when they have a chance to succeed. By the end, your app will handle routine syncs, deferred uploads, and maintenance tasks predictably, without brittle timers or reliance on foreground screens.