Mobile App Architecture and Lifecycle Questions

Knowledge of mobile application architecture and lifecycle across platform families, covering platform specific components, lifecycle states and methods, common architectural patterns, and cross platform considerations. For Android this includes application components such as Activities, Services, Content Providers, and Broadcast Receivers; mastery of the Activity lifecycle callbacks including onCreate, onStart, onResume, onPause, onStop, and onDestroy and the conditions under which they are invoked; the role and lifecycle of Fragments as modular user interface components; process priority and how the operating system manages process termination and resource reclamation; and modern Android architecture components and patterns such as ViewModel and observable data patterns. For iOS this includes the application entry points and delegates such as App Delegate and Scene Delegate and the role of the application window, the app lifecycle states Not Running, Inactive, Active, Background, and Suspended and the timing of transitions; the view controller hierarchy and view lifecycle callbacks such as viewDidLoad, viewWillAppear, viewDidAppear, viewWillDisappear, and viewDidDisappear; and common architecture patterns including Model View Controller and Model View View Model as applied on the platform. Also include cross cutting topics such as state restoration, background execution and task scheduling, memory and resource management, handling configuration and orientation changes, user interface composition frameworks, testing strategies for lifecycle dependent code, and trade offs when mapping architectures across Android and iOS.