NSUserDeafaults / Saving User Settings

It’s a very common practice to save/persist settings, preferences and  login credentials in our applications.  Apple has made this task very easy for us via the NSUserDefaults object. Below is a quick step by step of how to use it.

Step 1:

Instantiate NSUserDefaults:

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
Step 2:

Set a default in the following manner, this just your typical objecting setting for a key value pair (dictionary).

[prefs setObject:@"my value" forKey:@"my_setting"];

Synchronize your settings

[prefs synchronize];

Step 3:

Read the preference back later.

[prefs stringForKey:@"my_setting"];

NOTE:

The one thing to pay attention to here is the data type. In this case I am asking for a string, but you may use other data types check out the methods below


- (NSString *)stringForKey:(NSString *)defaultName;
- (NSArray *)arrayForKey:(NSString *)defaultName;
- (NSDictionary *)dictionaryForKey:(NSString *)defaultName;
- (NSData *)dataForKey:(NSString *)defaultName;
- (NSArray *)stringArrayForKey:(NSString *)defaultName;
- (NSInteger)integerForKey:(NSString *)defaultName;
- (float)floatForKey:(NSString *)defaultName;
- (double)doubleForKey:(NSString *)defaultName;
- (BOOL)boolForKey:(NSString *)defaultName;
- (NSURL *)URLForKey:(NSString *)defaultName


Now once you set your NSUserDefault it will be saved to your app and persist between launches.

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