RxModal

RxModal enforces the simple idea that a modal flow can be considered as a simple asynchroneous event:

• the view controller is presented on subscribe
• the user do what they want to do in the modal view
• the view controller is dismissed on dispose and eventually emit a value or an error

Usage

Here's an example

In Action

let mailComposer = RxModal.mailComposer { $0.setToRecipients([ "[email protected]" ]) $0.setMessageBody( "Hello World!", isHTML: false ) } let messageComposer = RxModal.messageComposer { $0.recipients = ["0639981337"] $0.body = "Hello World!" } contactUsButton .rx.tap .flatMapFirst { [unowned contactUsButton] in RxModal.actionSheet( source: .bounds(contactUsButton), actions: [ .default( title: "Mail", flatMapTo: mailComposer ), .default( title: "Message", flatMapTo: messageComposer ), .cancel(title: "Cancel") ]) } .subscribe() .disposed(by: disposeBag)

Supported Modals

// MFMailComposeViewController
RxModal.mailComposer() -> Single<MFMailComposeResult>

// MFMessageComposeViewController
RxModal.messageComposer() -> Single<MessageComposeResult>

// MPMediaPickerController
RxModal.mediaPicker() -> Single<MPMediaItemCollection>

// PHPickerViewController
RxModal.photoPicker() -> Single<[PHPickerResult]>

// ASWebAuthenticationSession
RxModal.webAuthenticationSession(url:callbackURLScheme:) -> Single<URL>

// UIAlertController
RxModal.alert<T>(title:message:textFields:actions:) -> Observable<T>
RxModal.actionSheet<T>(source:title:message:actions:) -> Observable<T>

Presenter

All these functions also include a presenter: Presenter argument that allows you to choose where the modal will be presented. Presenters are just lazy UIViewController getters:

.viewController(_:) -> $0
.view(_:) -> $0.window?.rootViewController
.window(_:) -> $0.rootViewController 
.scene(_:) -> $0.windows.first?.rootViewController
.keyWindow -> UIApplication.shared.keyWindow?.rootViewController

Default is .keyWindow. On iPad or macCatalyst allowing multiple windows, we discourage you to use .keyWindow or .scene(_:) as it might select the wrong window.

Configuration

These functions also include a configuration closure : (ViewController) -> Void that will let you configure the view controller before presentation.

If a modal requires some parameters at init time, they will be part of the RxModal function (ex: ASWebAuthenticationSession, UIAlertController).

Preconditions

Some RxModals perform precondition checks before presenting the modal and emit a RxModalError.unsupported if they aren't fulfilled:

• RxModal.mailComposer() → MFMailComposeViewController.canSendMail()
• RxModal.messageComposer() → MFMessageComposeViewController.canSendText()

Some RxModals perform an authorization status check before presenting the modal and either request authorization, or emit a RxModalError.authorizationStatusDenied(Any) if authorization is denied:

• RxModal.mediaPicker() → MPMediaLibrary.authorizationStatus()

Dialogs

RxModal.alert() and RxModal.actionSheet() allows you to define actions that are converted to a new Observable stream, a value, or an error:

DialogAction<T>.default(title:flatMapTo: Observable<T>)
DialogAction<T>.default(title:mapTo: T) // == flatMapTo: Observable.just(T)
DialogAction<T>.default(title:throw: Error) // == flatMapTo: Observable.error(Error)
DialogAction<T>.default(title:) // == flatMapTo: Observable.empty()

RxModal.alert() also let you configure alert text fields:

RxModal.alert(
    title: "Sign in",
    message: "Please sign in using your credentials",
    textFields: [
        DialogTextField.email { $0.placeholder = "e-mail" },
        DialogTextField.password { $0.placeholder = "password" }
    ],
    actions: [
        .cancel(title: "Cancel"),
        .default(title: "Sign In") { textFields in
            Credentials(
                email: textFields[0].text ?? "",
                password: textFields[1].text ?? ""
            )
        },
    ]
)

Extending RxModal

You can easily extend RxModal with your own controllers / modal flows.

If your controller is already returning its output using Rx, it's easy:

class MyModalViewController: UIViewController {
    let myResult = PublishSubject<MyResult>()
    // ...
}

extension RxModal {
    func myModal(
        presenter: Presenter = .keyWindow,
        configuration: @escaping (MyModalViewController) -> Void
    ) -> Single<MyResult> {
        RxModalCoordinator<MyModalViewController>.present(using: presenter) { _ in
            let modal = MyModalViewController()
            configuration(modal)
            return modal
        } sequence: {
            $0.viewController.myResult.asSingle()
        }
    }
}

If your controller is rather using a traditional delegate approach, you'll need to subclass RxModalCoordinator:

protocol MyModalViewControllerDelegate: AnyObject {
    func myModal(_ myModal: MyModalViewController, didFinishWith result: MyResult)
    func myModal(_ myModal: MyModalViewController, didFinishWithError error: Error)
}

class MyModalViewController: UIViewController {
    weak var delegate: MyModalViewControllerDelegate?
    // ...
}

extension RxModal {
    func myModal(
        presenter: Presenter = .keyWindow,
        configuration: @escaping (MyModalViewController) -> Void
    ) -> Single<MyResult> {
        
        MyModalViewControllerCoordinator.present(using: presenter) { coordinator in
            let modal = MyModalViewController()
            modal.delegate = coordinator
            configuration(modal)
            return modal
        } sequence: {
            $0.myResult.asSingle()
        }
        
    }
}

final class MyModalViewControllerCoordinator: RxModalCoordinator<MyModalViewController>, MyModalViewControllerDelegate {
    required init(){}
    
    let myResult = PublishSubject<MyResult>()
    
    func myModal(_ myModal: MyModalViewController, didFinishWith result: MyResult) {
        myResult.onNext(result)
        myResult.onCompleted()
    }
    
    func myModal(_ myModal: MyModalViewController, didFinishWithError error: Error) {
        myResult.onError(error)
    }

}

If your controller is embedded in a non UIViewController object, you won't be able to leverage on RxModalCoordinator and you'll need to handle all the present/dismiss boilerplate. See ASWebAuthenticationSession.swift as an example.

Author

Jérôme Alves

License

RxModal is available under the MIT license. See the LICENSE file for more info.