InAppSettingsKit is an open source solution to to easily add in-app settings to your iPhone apps. It uses a hybrid approach by maintaining the Settings.app pane. So the user has the choice where to change the settings. More details about the history of this development on the FutureTap Blog and the Edovia Blog.

To support traditional Settings.app panes, the app must include a Settings.bundle with at least a Root.plist to specify the connection of settings UI elements with NSUserDefaults keys. InAppSettingsKit basically just uses the same Settings.bundle to do its work. This means there's no additional work when you want to include a new settings parameter. It just has to be added to the Settings.bundle and it will appear both in-app and in Settings.app. All settings types like text fields, sliders, toggle elements, child views etc. are supported.

We released the code under the liberal BSD license in order to make it possible to include it in every project, be it a free or paid app. The only thing we ask for is giving the original developers some credit. The easiest way to include credits is by leaving the "Powered by InAppSettingsKit" notice in the code. If you decide to remove this notice, a noticeable mention on the App Store description page or homepage is fine, too. To gain some exposure for your app we suggest adding your app to our list.

The source code is available on github. Basically you have 2 options of including InAppSettingsKit:

1. you copy the InAppSettingsKit subfolder into your project and drag the files right into your application. InAppSettingsKitSampleApp.xcodeproj demonstrates this scenario. If your project is compiled without ARC, you'll need to enable it for the IASK files. You can do so by adding -fobjc-arc in the "Compile Sources" phase. You can select all the relevant files at once with shift-click and then double-click in the Compiler Flags column to enter the text.

2. you can use the static library project to include InAppSettingsKit. To see an example on how to do it, open InAppSettingsKit.xcworkspace. It includes the sample application that uses the static library as well as the static library project itself. To include the static library project there are only a few steps necessary (the guys at HockeyApp have a nice tutorial about using static libraries, just ignore the parts about the resource bundle):

• add the InAppSettingsKit.xcodeproject into your application's workspace
• add libInAppSettingsKit.a to your application's libraries by opening the Build-Phases pane of the main application and adding it in Link Binary with Libraries
• use IASK by importing it via #import "InAppSettingsKit/..."
• for Archive builds there's a minor annoyance: To make those work, you'll need to add $(OBJROOT)/UninstalledProducts/include to the HEADER_SEARCH_PATHS

Then you can display the InAppSettingsKit view controller using a navigation push, as a modal view controller or in a separate tab of a TabBar based application. The sample app demonstrates all three ways to integrate InAppSettingsKit.

Depending on your project it might be needed to make some changes in the startup code of your app. Your app has to be able to reconfigure itself at runtime if the settings are changed by the user. This could be done in a -reconfigure method that is being called from -applicationDidFinishLaunching as well as in the delegate method -settingsViewControllerDidEnd: of IASKAppSettingsViewController.

You may need to make two changes to your project to get it to compile: 1) Add MessageUI.framework and 2) enable ARC for the IASK files. Both changes can be made by finding your target and navigating to the Build Phases tab.

MessageUI.framework is needed for MFMailComposeViewController and can be added in the "Link Binary With Libraries" Section. Use the icon.

To enable ARC select all IASK* source files in the "Compile Sources" section, press Enter, insert -fobjc-arc and then "Done".

To sync your NSUserDefaults with iCloud, there's another project called FTiCloudSync which is implemented as a category on NSUserDefaults: All write and remove requests are automatically forwarded to iCloud and all updates from iCloud are automatically stored in NSUserDefaults. InAppSettingsKit automatically updates the UI if the standard NSUserDefaults based store is used.

The intention of InAppSettingsKit was to create a 100% imitation of the Settings.app behavior. However, we added some bonus features for extra flexibility.

Since iOS 4 Settings plists can be device-dependent: Root~ipad.plist will be used on iPad and Root~iphone.plist on iPhone. If not existent, Root.plist will be used. InAppSettingsKit adds the possibility to override those standard files by using .inApp.plist instead of .plist. Alternatively, you can create a totally separate bundle named InAppSettings.bundle instead of the usual Settings.bundle. The latter approach is useful if you want to suppress the settings in Settings.app.

In summary, the plists are searched in this order:

• InAppSettings.bundle/FILE~DEVICE.inApp.plist
• InAppSettings.bundle/FILE.inApp.plist
• InAppSettings.bundle/FILE~DEVICE.plist
• InAppSettings.bundle/FILE.plist
• Settings.bundle/FILE~DEVICE.inApp.plist
• Settings.bundle/FILE.inApp.plist
• Settings.bundle/FILE~DEVICE.plist
• Settings.bundle/FILE.plist

Different in-app settings are useful in a variety of situations. For example, Where To? uses this mechanism to change the wording of "At next start" (for resetting confirmation dialogs) to be appropriate if the app is already running.

InAppSettingsKit adds a new element that allows to open a specified URL using an external application (i.e. Safari or Mail). See the sample Root.inApp.plist for details.

The custom IASKMailComposeSpecifier element allows to send mail from within the app by opening a mail compose view. You can set the following (optional) parameters using the settings plist: IASKMailComposeToRecipents, IASKMailComposeCcRecipents, IASKMailComposeBccRecipents, IASKMailComposeSubject, IASKMailComposeBody, IASKMailComposeBodyIsHTML. Optionally, you can implement

- (NSString*)settingsViewController:(id<IASKViewController>)settingsViewController mailComposeBodyForSpecifier:(IASKSpecifier*)specifier;

in your delegate to pre-fill the body with dynamic content (great to add device-specific data in support mails for example). An alert is displayed if Email is not configured on the device. IASKSpecifier is the internal model object defining a single settings cell. Important IASKSpecifier properties:

• key: corresponds to the Key in the Settings plist
• title: the localized title of settings key
• type: corresponds to the Type in the Settings plist
• defaultValue: corresponds to the DefaultValue in the Settings plist

InAppSettingsKit adds a IASKButtonSpecifier element that allows to call a custom action. Just add the following delegate method:

- (void)settingsViewController:(IASKAppSettingsViewController*)sender buttonTappedForSpecifier:(IASKSpecifier*)specifier;

The sender is always an instance of IASKAppSettingsViewController, a UIViewController subclass. So you can access its view property (might be handy to display an action sheet) or push another view controller. Another nifty feature is that the title of IASK buttons can be overriden by the (localizable) value from NSUserDefaults (or any other settings store - see below). This comes in handy for toggle buttons (e.g. Login/Logout). See the sample app for details.

By default, Buttons are aligned centered except if an image is specified (default: left-aligned). The default alignment may be overridden.

The FooterText key for Group elements is available in system settings since iOS 4. It is supported in InAppSettingsKit as well. On top of that, we support this key for Multi Value elements as well. The footer text is displayed below the table of multi value options.

You can specify your own UITableViewCell within InAppSettingsKit by using the type IASKCustomViewSpecifier. A mandatory field in this case is the Key attribute. Also, you have to support the IASKSettingsDelegate protocol and implement these methods:

- (CGFloat)tableView:(UITableView*)tableView heightForSpecifier:(IASKSpecifier*)specifier;
- (UITableViewCell*)tableView:(UITableView*)tableView cellForSpecifier:(IASKSpecifier*)specifier;

Both methods are called for all your IASKCustomViewSpecifier entries. To differentiate them, you can access the Key attribute using specifier.key. In the first method you return the height of the cell, in the second method the cell itself. You should use reusable UITableViewCell objects as usual in table view programming. There's an example in the Demo app. Optionally you can implement

- (void)settingsViewController:(IASKAppSettingsViewController*)sender tableView:(UITableView *)tableView didSelectCustomViewSpecifier:(IASKSpecifier*)specifier;

to catch tap events for your custom view.

You can define custom headers for PSGroupSpecifier segments by adding a Key attribute and implementing these methods in your IASKSettingsDelegate:

- (CGFloat)settingsViewController:(id<IASKViewController>)settingsViewController tableView:(UITableView*)tableView heightForHeaderForSection:(NSInteger)section;
- (UIView*)settingsViewController:(id<IASKViewController>)settingsViewController tableView:(UITableView *)tableView viewForHeaderForSection:(NSString*)key;

The behaviour is similar to the custom cells except that the methods get the key directly as a string, not via a IASKSpecifier object. (The reason being that custom group header views are meant to be static.) Again, check the example in the demo app.

For child pane elements (PSChildPaneSpecifier), Apple requires a file key that specifies the child plist. InAppSettingsKit allow to alternatively specify IASKViewControllerClass and IASKViewControllerSelector. In this case, the child pane is displayed by instantiating a UIViewController subclass of the specified class and initializing it using the init method specified in the IASKViewControllerSelector. The selector must have two arguments: an NSString argument for the file name in the Settings bundle and the IASKSpecifier. The custom view controller is then pushed onto the navigation stack. See the sample app for more details.

Alternatively specify IASKViewControllerStoryBoardId to initiate a viewcontroller from main storyboard. Specifiy IASKViewControllerStoryBoardFile to use a story board other than MainStoryboard file.

For some element types, a IASKTextAlignment attribute may be added with the following values to override the default alignment:

• IASKUITextAlignmentLeft (Buttons, TitleValue, MultiValue, OpenURL, TextField)
• IASKUITextAlignmentCenter (Buttons, OpenURL)
• IASKUITextAlignmentRight (Buttons, TitleValue, MultiValue, OpenURL, TextField)

By default, the labels in the settings table are displayed in a variable font size, especially handy to squeeze-in long localizations (beware: this might break the look in Settings.app if labels are too long!). To disable this behavior, add a IASKAdjustsFontSizeToFitWidth Boolean attribute with value NO.

All element types (except sliders which already have a MinimumValueImage) support an icon image on the left side of the cell. You can specify the image name in an optional IASKCellImage attribute. The ".png" or "@2x.png" suffix is automatically appended and will be searched in the project. Optionally, you can add an image with suffix "Highlighted.png" or "[email protected]" to the project and it will be automatically used as a highlight image when the cell is selected (for Buttons and ChildPanes).

The default behaviour of IASK is to store the settings in [NSUserDefaults standardUserDefaults]. However, it is possible to change this behavior by setting the settingsStore property on an IASKAppSettingsViewController. IASK comes with two store implementations: IASKSettingsStoreUserDefaults (the default one) and IASKSettingsStoreFile, which read and write the settings in a file of the path you choose. If you need something more specific, you can also choose to create your own store. The easiest way to create your own store is to create a subclass of IASKAbstractSettingsStore. Only 3 methods are required to override. See IASKSettingsStore.{h,m} for more details.

There's a kIASKAppSettingChanged notification that is sent for every changed settings key. The object of the notification is the userDefaults key (NSString*). The userInfo dictionary contains the new value of the key.

Sometimes, options depend on each other. For instance, you might want to have an "Auto Connect" switch, and let the user set username and password if enabled. To react on changes of a specific setting, use the kIASKAppSettingChanged notification explained above.

To hide a set of cells use:

- (void)[IASKAppSettingsViewController setHiddenKeys:(NSSet*)hiddenKeys animated:(BOOL)animated];

or the non-animated version:

@property (nonatomic, retain) NSSet *hiddenKeys;

See the sample app for more details. Note that InAppSettingsKit uses Settings schema, not TableView semantics: If you want to hide a group of cells, you have to include the Group entry as well as the member entries.

If you'd like to customize the appearance of InAppSettingsKit, you might want to subclass IASKAppSettingsViewController and override some UITableViewDataSource or UITableViewDelegate methods.

In the Dr. Touch podcast and the MDN Show Episode 027 Ortwin Gentz talks about InAppSettingsKit.