BindKit

A simple to use two-way data binding framework for iOS. Only one API to learn.

Supports Objective-C and Swift, Xcode 8 and 9, Swift 3 and 4, iOS 8 and above.

Ships as a static library ready for you to link into your app (or you can include the source directly into your project). The static library is built as a 'fat' library and includes the following architectures: i386, x86_64, armv7s, armv7, arm64 and bitcode.

Currently supported views

The following views are supported directly by BindKit:

Don't see the property or class you're interested in? Submit a pull request with your changes to add the property or class, or use the Vendor API to add custom functionality in your own app. See MySearchBar.swift in BindingExample for an example of custom functionality using the Vendor API.

Binding

Data binding is two-way - any changes to your models properties are automatically applied to your views properties and vice versa.

There is only one API to learn:

Objective-C

[model bindObjectSel: @selector(addressStr) toView: addressTextField viewKey: UITextFieldText];

Swift

model.bindObjectKey(#keyPath(model.addressStr), toView: addressTextField, viewKey: UITextFieldText)

Just a few simple rules

The following rules apply when using BindKit with Swift:

1. Your model object must inherit from NSObject.
2. Your models properties that participate in binding need to be marked dynamic.

See under the hood for implementation details.

Example

Swift

class LogonModel: NSObject {
	
	dynamic var username: String!
	dynamic var password: String!
	dynamic var logonEnabled: Boolean
	
	override func boundPropertiesDidUpdate() {
		logonEnabled = validate()
	}

	func validate() -> Boolean
		guard username!.trimmingCharacters(in: CharacterSet.whitespaces).count > 0 else { return false }
		guard password!.trimmingCharacters(in: CharacterSet.whitespaces).count > 0 else { return false }
		return true
	}
}

class LogonController: UITableViewController {

	@IBOutlet weak var usernameTextField: UITextField!
	@IBOutlet weak var passwordTextField: UITextField!
	@IBOutlet weak var logonButton: UIButton!

	var model = LogonModel()

	override func viewDidLoad() {
		model.bindKey(#keyPath(model.username), view: usernameTextField, viewKey: UITextFieldText)
		model.bindKey(#keyPath(model.password), view: passwordTextField, viewKey: UITextFieldText)
		model.bindKey(#keyPath(model.logonEnabled), view: logonButton, viewKey: UIButtonEnabled)
	}

}

Adding BindKit to your app

• Link libBindKit.a into your app
• Configure Header Search Paths to allow Xcode to find BindKit.h and BindKitVendor.h
• Add -ObjC and -all_load to Other Linker Flags

Building

Whilst the libBindKit.a static library is prebuilt and included in the repository, if you need to rebuild then execute the following command:

./buildlibrary.sh

The resulting static library and header files will be placed into the release directory.

The build script currently assumes Xcode 9/SDK11.2. If you are using a different Xcode build chain, tweak the IOSSDK_VER variable in the build script as appropriate.

Under the hood

Model

Model properties that participate in binding are monitored for changes using Key-Value-Observing (KVO). For this reason model objects must inherit from NSObject, and if using Swift, properties must be marked with dynamic.

View

Views that participate in binding are dynamically subclassed at runtime. There is one dynamic subclass implemented for each supported view. Depending on the view, different methods for monitoring changes are required: target-action, delegation or notifications.

View not supported? Submit a pull request with your changes to add the property or class, or use the Vendor API to add custom functionality in your own app.