NSUserDefaults更改了更新后IOS应用崩溃

Question

updated IOS app with changes in NSUser default keys ( added few more keys and changed some existing key names) app is crashing at initialization time after updating from store . If I delete the app completely and reinstall it then it is working fine . We can not clear previous NSUser defaults and recreate it when updating app ( I mean complete re-installation by writing some logic in updated app)?.

Answer 1

您可以使用以下代码清除NSUserDefault 。

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

Answer 2

try to synchronize the user defaults

[[NSUserDefaults standardUserDefaults] removeObjectForKey:@"YourKey"];
[[NSUserDefaults standardUserDefaults] synchronize];yourkey

Answer 3

我建议编写一个迁移器例程，以在应用程序启动并分别更新默认数据库时检查某些以前的密钥。

Answer 4

您通常可以通过执行以下操作清除整个NSUserDefaults，以防万一您忘记了密钥或其他东西：

   [[NSUserDefaults standardUserDefaults] setPersistentDomain:[NSDictionary dictionary]  forName:[[NSBundle mainBundle] bundleIdentifier]];

Answer 5

You can check if app is opening for first time then clear NSUserDefault as below

[[NSUserDefaults standardUserDefaults] setPersistentDomain:[NSDictionary dictionary]  forName:[[NSBundle mainBundle] bundleIdentifier]];

After that set your NSUserDefault again as per your requirement.