With the investigation I’ve been doing in building an iOS application using Xamarin, I’ve now gotten to the point where I wanted to put some settings into the iOS Setting app for my application. I found this nice thread that gave the 3 easy steps to set up a settings bundle.

It literally is as simple as written, but there were a couple gotchas that I ran into that I wanted to forward along.

1. The Settings.bundle folder needs to be in the project root, NOT under the Resources folder (where some examples showed it). I’m not sure if this is a new change or not, but I spent some time banging my head against the wall over this one.
2. If you do not register default values for your settings they’ll return the default for the data type. (ie. null for String, false for bool, etc….). The DefaultValue you specify in the Root.plist file for a setting is the default value the control will show, NOT the value of the setting. Below is an example of registering default values for settings.

NSUserDefaults userDefaults = NSUserDefaults.StandardUserDefaults;
NSMutableDictionary appDefaults = new NSMutableDictionary(); 
appDefaults.SetValueForKey( NSObject.FromObject( true ), new NSString( "BooleanSettingKey" ) );
userDefaults.RegisterDefaults( appDefaults );
userDefaults.Synchronize();

Accessing the value for a setting is a simple as the following:

bool settingValue = NSUserDefaults.StandardUserDefaults.BoolForKey( "BooleanSettingKey");

One last thing that I found in an example solution here was how to listen in your app for when settings have been changed and wanted to pass it along:

NSObject observer = NSNotificationCenter.DefaultCenter.AddObserver( (NSString)"NSUserDefaultsDidChangeNotification", DefaultsChanged ); 
private void DefaultsChanged( NSNotification obj )
{ 	
// Handle the settings changed 
}

The biggest bummer I found in the iOS Settings Bundle is that everything is statically defined. So if you happen to have a collection of items that you want updated from a server, you’ll have to do this on your own inside your application.