A small extension for registering NSUserDefaults default values using its registerDefaults method from the default values of a settings bundle. See http://oleb.net/blog/2014/02/nsuserdefaults-handling-default-values/ for more information on NSUserDefaults and default values. The code respects an ApplicationGroupContainerIdentifier key and uses N…

RegisterSettingsBundleDefaults.swift

import Foundation

if let bundleURL = NSBundle.mainBundle().URLForResource("Settings", withExtension: "bundle") {
    NSUserDefaults.registerDefaults(settingsBundleURL: bundleURL)
}

extension NSUserDefaults {
    static func registerDefaults(#settingsBundleURL: NSURL) {
        if let rootDict = NSDictionary(contentsOfURL: settingsBundleURL.URLByAppendingPathComponent("Root.plist")) {
            var defaults: NSUserDefaults?
            if let containerIdentifier = rootDict.valueForKey("ApplicationGroupContainerIdentifier") as? String {
                defaults = NSUserDefaults(suiteName: containerIdentifier)
            } else {
                defaults = NSUserDefaults.standardUserDefaults()
            }
            if let defaults = defaults, preferences = rootDict.valueForKey("PreferenceSpecifiers") as? [[String:AnyObject]] {
                var registrationDictionary: [NSObject:AnyObject] = [:]
                for prefs in preferences {
                    if let type = prefs["Type"] as? String {
                        switch type {
                        case "PSToggleSwitchSpecifier":
                            if let boolValue = prefs["DefaultValue"] as? Bool, let key = prefs["Key"] as? String {
                                registrationDictionary[key] = boolValue
                            }
                        case "PSSliderSpecifier":
                            if let floatValue = prefs["DefaultValue"] as? Float, let key = prefs["Key"] as? String {
                                registrationDictionary[key] = floatValue
                            }
                        case "PSTextFieldSpecifier", "PSMultiValueSpecifier":
                            if let textValue = prefs["DefaultValue"] as? String, let key = prefs["Key"] as? String {
                                registrationDictionary[key] = textValue
                            }
                        default:
                            continue
                        }
                    }
                }
                defaults.registerDefaults(registrationDictionary)
            }
        }
    }
}