//方法一

NSString*appDomain = [[NSBundlemainBundle]bundleIdentifier];

[[NSUserDefaultsstandardUserDefaults]removePersistentDomainForName:appDomain];

//方法二

- (void)resetDefaults {

NSUserDefaults* defs = [NSUserDefaultsstandardUserDefaults];

NSDictionary* dict = [defsdictionaryRepresentation];

for(idkeyindict) {

[defsremoveObjectForKey:key];

}

[defssynchronize];

}