NSUserDefaults关闭应用程序时删除键

Question

I need to delete keys when application will close. So what should I do?

Answer 1

Delete keys from NSUserDefaults using the following code

[[NSUserDefaults standardUserDefaults] removeObjectForKey:@"yourKey"];

in your ApplicationDelegate method following which state are you meaning by "close the app":

- (void)applicationWillResignActive:(UIApplication *)application
- (void)applicationDidEnterBackground:(UIApplication *)application
- (void)applicationWillTerminate:(UIApplication *)application

Answer 2

Look in the documentation

- removeObjectForKey:

Removes the value of the specified default key in the standard application domain.