Explain the difference between Background vs Suspended app state
Câu trả lời
In iOS development, understanding the difference between the Background and Suspended app states is crucial for managing app behavior and resource usage effectively. Here is a detailed explanation of these two states:
Background State
Definition: When an app is in the Background state, it is not visible to the user but is still running and capable of executing code.
Usage: Apps in this state can perform tasks such as playing audio, updating location data, or downloading content. This state is typically used for short tasks that need to be completed even when the app is not in the foreground.
Duration: The app can remain in the Background state for a limited time. By default, this period is about 10 seconds, but apps can request additional time (up to 180 seconds) to complete specific tasks[4].
Transition: The transition to the Background state is triggered by the applicationDidEnterBackground callback. Before entering this state, the app receives the applicationWillResignActive method call[4].
Suspended State
Definition: In the Suspended state, the app is still resident in memory but is not executing any code. Essentially, the app is "frozen" and does not consume CPU resources.
Usage: This state is used to preserve the app's state in memory without actively running any tasks. The system can quickly resume the app from this state, making it faster than restarting the app from scratch.
Duration: The app remains in the Suspended state until the system needs to free up memory. If the system is under memory pressure, it may terminate suspended apps to reclaim resources[1][6].
Transition: The transition to the Suspended state happens automatically after the app has been in the Background state for a while and has completed its background tasks. The system does not notify the app when it moves to the Suspended state[6].
