NSUserDefaults没有保存在模拟器中？

Question

My [NSUserDefaults standardUserDefaults] are not being saved. Everything I close the app and start it again, it reverts back. I don't have my iOS device handy so I am not sure if this will happen on device, but none of the other apps are doing this in simulator which leads me to believe there's something wrong with my code. I don't know what part of code I should include here, it's just simple add/modify keys in nsuserdefaults and as i said it runs fine during the app, but not after i restart it...

I know I can call synchronize but Apple advices against it and says I should only call it if it's a must..so.

What could be going wrong? Thanks.

Answer 1

Your process is possibly terminated improperly so that NSUserDefaults do not have a chance to be stored. See also this and mostly this .

The suggestion in the second post I link to is to call synchronize in applicationDidEnterBackground:

Keep also in mind that terminating your app by stopping it in Xcode most often does not save user defaults.

Answer 2

Are you restarting from Xcode / debugger? Try sending the app to background with the Home button first. I think the framework synchronizes automatically then.

Answer 3

I could not understand about the way, you are accessing the NSUserDefault , The static function you used sharedDefaults with NSUserDefault does'nt exist in Apple Documentation

Use As below to access NSUserDefault

[NSUserDefaults standardUserDefaults];

For more read the blog post for using of NSUserDefault .

iPhone Programming Tutorial – Saving/Retrieving Data Using NSUserDefaults