How does Android handle multitasking?

Android employs various mechanisms to handle multitasking and provide a smooth and efficient user experience. Here are some key aspects of how Android handles multitasking:

1. Process Lifecycle: Android uses a process-based approach to manage multitasking. Each application runs in its own process, which is an isolated instance of the application in memory. Android manages the lifecycle of these processes based on system resources and user interactions.
2. Activity Stack: Android uses an activity stack to manage the user interface (UI) and the flow of activities within an application. When a new activity is launched, it is pushed onto the stack, and the user interacts with the topmost activity. Activities can be paused, resumed, or stopped based on the user’s actions or system events.
3. Background Execution Limits: To optimize performance and battery life, Android imposes certain limitations on background execution. Starting from Android 8.0 (Oreo), background apps have restrictions on accessing system resources and running in the background for an extended period. This ensures that foreground apps receive priority and background apps consume minimal resources.
4. Task Switching: Android allows users to switch between different tasks (applications) seamlessly. Users can use the Overview (recent apps) button or gesture to view and switch between the recently used applications. When a user switches to a different task, the previously active task is paused or stopped, depending on the system’s resource requirements.
5. Background Services: Android provides background services for applications to perform tasks that don’t require a user interface. Services can run in the background even when the associated application is not in the foreground. However, starting from Android 8.0, background services are subject to limitations and restrictions to prevent excessive resource usage.
6. Notifications and Background Updates: Android allows applications to provide notifications to users, even when the application is not actively running. Notifications can provide relevant information or alert users about updates, messages, or events. Applications can also schedule background updates or sync data periodically to keep the app content up to date.
7. Multi-Window Support: Starting from Android 7.0 (Nougat), Android introduced native multi-window support, allowing users to run multiple applications simultaneously in split-screen or picture-in-picture mode. This feature enhances multitasking capabilities and enables users to interact with multiple apps concurrently.
8. Background Task Management: Android employs various strategies to manage background tasks efficiently. It uses techniques like job scheduling, alarms, and priority-based task management to optimize resource usage, ensure timely execution of tasks, and minimize battery drain.

These mechanisms and strategies employed by Android help provide a multitasking environment where users can seamlessly switch between applications, perform background tasks, receive notifications, and manage system resources efficiently.