Storing variables during lifetime of the ios app

Question

What happens to the app when it is killed/terminated from the multitasking tray (i.e double click the home button and delete it from there)? And i relaunch the app again by clicking on it? Consider this scenario. I save some variables (global variables) and i save some values to them. I killed/deleted the app from multitasking tray and relaunched it. I no longer have variable values. How can i store them through the entire process of app life cycle and they can be changed when someone changes within the app life cycle. If you need more information please ask. I have been saving the values to a plist file.I created a settings bundle and saving values to them as global variables..is it the way to go?

Answer 1

To save data even after the app is killed/terminated, you have to use persistent storage. There are a number of different ways to do this. A few of these ways are using NSUserDefaults, plists, or CoreData.

See these links, and try to find out what's best for what you're trying to do.

iOS persistent storage strategy

Use SQLite, plist, or something else?

You should also check out the iOS development lectures, there's two parts and the first part covers persistent storage in great detail. It's called Effective iPhone App Development. I recommend watching both, but the first part of the first one would answer your questions.

https://developer.apple.com/videos/ios/