按下按钮时可观察到 RxSwift 触发器

Posted 2023-03-10

【中文标题】按下按钮时可观察到 RxSwift 触发器

【英文标题】：RxSwift trigger observable on button tap

【发布时间】：2017-10-30 02:18:31

【问题描述】：

我正在创建一个自定义的 observable，它将呈现一个 UIAlertController，它希望在按下时触发 API 调用。但是，除非我手动订阅它，否则我似乎无法弹出警报。有没有办法从 viewModel 触发这个？

MyController.swift

class MyController: UIViewController 
    @IBOutlet weak var nextBarButton: UIBarButtonItem!

    var viewModel: ViewModel!

    override func viewDidLoad() 
        super.viewDidLoad()


        viewModel = ViewModel( nextBarButton.rx.tap.asDriver(), alertController()asDriver(onErrorJustReturn: ""))
    

    func alertController() -> Observable<String> 
        return Observable.create  [weak alert = self] observer in
            guard let alert = alert else 
                observer.on(.completed)
                return Disposables.create()
            

            let alertVc = UIAlertController(title: "My Title", message: "My Message", preferredStyle: .alert)
            let submit = UIAlertAction(title: "Continue", style: .default)  _ in
                observer.onNext("Test")
                observer.on(.completed)
            
            let cancel = UIAlertAction(title: "Cancel", style: .cancel)  _ in
                observer.on(.completed)
            
            alertVc.addAction(cancel)
            alertVc.addAction(submit)
            alert.present(alertVc, animated: true, completion: nil)

            return Disposables.create 
                alertVc.dismiss(animated: true, completion: nil)
            
        
    

ViewModel.swift

public final class ViewModel 
    init(_ manager: SessionManager, _ trigger: Driver<Void>, _ alert: Driver<String>) 
        let _ = trigger.withLatestFrom(alert)
            .flatMap  text in
                return manager.rx
                    .request(urlRequest: Api.test)
                    .retry(3)
                    .asDriverOnErrorJustComplete()
            
    

【参考方案1】：

您在ViewModel 中忘记了subscribe()，当链接来自UIButton 的事件时，您应该flatMapLatest。它应该看起来像：

public final class ViewModel 
    init(_ manager: SessionManager, _ trigger: Driver<Void>, _ alert: Driver<String>) 
        let _ = trigger.flatMapLatest alert 
            .flatMap  text in
                return manager.rx
                    .request(urlRequest: Api.test)
                    .retry(3)
                    .asDriverOnErrorJustComplete()
            
            .subscribe()