ios - UI未在ViewController MVVM中更新

Question

我正在 swift 学习MVVM。我正确设置了viewModel，但是ui并未更新，实际上我将服务作为单例服务参数做了什么错？这是我的代码设置

class UserViewModel {

    private var user: GTUser?
    let service: UserService

    var id: String {
        return user?.userId ?? ""
    }

    var userName: String {
        return user?.fullName ?? ""
    }

    var imageUrl: String {
        return user?.docAwsUrl ?? ""
    }

    init(service: UserService) {
        self.service = service
        populateUser()
    }

    private func populateUser() {
        service.getUserData { result in
            switch result {
            case .success(let user):
                self.user = user
                print(self.user)
            case .failure(let error):
                print(error)
            }
        }
    }
}

let services = UserService()
var viewModel: UserViewModel!

override func viewDidLoad() {
        super.viewDidLoad()

        view.backgroundColor = .white
        setupNavigation()
        configure()

        viewModel = UserViewModel(service: services)

        DispatchQueue.main.async {
            self.profileImage.getUserImage(urlString: self.viewModel.imageUrl)
            self.profileLbl.text = self.viewModel.userName
        }
    }

我已经尝试使用dispatchQueue但仍然无法正常工作

Answer 1

您的private func populateUser()函数是异步函数，因此当您尝试从self.profileImage.getUserImage(urlString: self.viewModel.imageUrl)访问viewDidLoad时，它可能不可用，

因此，要解决此问题，您可以将完成处理程序闭包到函数中，并在成功和失败时调用完成处理程序，以便在执行操作之后

喜欢

您的init函数将关闭

init(service: UserService,completion:(Bool) -> ()) {
    self.service = service
    populateUser(completion)
}

和

private func populateUser(_ completion:(Bool) -> ()) {
   service.getUserData { result in
        switch result {
        case .success(let user):
            self.user = user
            print(self.user)
            completion(true)
        case .failure(let error):
            print(error)
           completion(false)
        }
    }
}

现在

 viewModel = UserViewModel(service: services){[unowned self] (success) in
        //Check success if you want !!
        self.profileImage.getUserImage(urlString: self.viewModel.imageUrl)
        self.profileLbl.text = self.viewModel.userName
    }            

希望对您有所帮助