两种方法删除NSUserDefaults所有记录

//方法一NSString *appDomain = [[NSBundle mainBundle] bundleIdentifier];[[NSUserDefaults standardUserDefaults] removePersistentDomainForName:appDomain]; 

//方法二- (void)resetDefaults {    NSUserDefaults * defs = [NSUserDefaults standardUserDefaults];    NSDictionary * dict = [defs dictionaryRepresentation];    for (id key in dict) {        [defs removeObjectForKey:key];    }    [defs synchronize];}