在ViewModel中将字符串从RxSwift中获取到View

Question

I am trying to get a string from ViewModel to View using PublishSubject() but View is not able to get it. Following is my code in ViewModel :

var myImageURL: PublishSubject<String> = PublishSubject<String>()

self.myService.getImage(materialNo: materialNumber).subscribe(
    onNext: { [weak self] imageURL in //I am able to get url here and want to send it to View, following doesn't work
        self?.myImageURL.onNext(imageURL)
        self?.myImageURL.onCompleted()
    },
    onError: { error in },
    onCompleted: { }
)
.disposed(by: disposeBag)

Code in View :

let disposeBag = DisposeBag()

self.viewModel.myImageURL.subscribe(
    onNext: { 
        print($0 + " image url")
        self.myImageView.af_setImage(withURL: URL(string: $0)!, placeholderImage:UIImage(named: "tool_placeholder"))
    },
    onError: {
        print(String(describing: $0).capitalized)
    }
)
.disposed(by: disposeBag)

Although viewModel code works fine but I am not able to receive its value in View .

Edit1: Updated code in view with drive:

self.viewModel.myImageURL
        .asObservable()
        .asDriver(onErrorJustReturn: "Error")
        .drive(onNext: {
                        self. myImageView.af_setImage(withURL: URL(string: $0)!, placeholderImage:UIImage(named: "tool_placeholder"))
                    }
            )
        .disposed(by: disposeBag)

Answer 1

Looks like you subscribing the incorrect value? You defined:

var toolImageURL: PublishSubject<String> = PublishSubject<String>()

in your viewModel, but called subscribe on viewModel.myImageURL .

Answer 2

the publish subject you're using should be 'bound' to the ImageView using a 'driver' to ensure its code it's running on the main thread (it could crash otherwise).

self.viewModel.myImageURL
  .asObservable()
  .asDriver(onErrorJustReturn: "Error")
  .drive(self.myImageView.af_setImage(withURL: URL(string: $0)!,
                               placeholderImage:UIImage(named: "tool_placeholder")))
  .addDisposableTo(self.disposeBag)

Try that firstly. Secondly, your code in the VM doesn't look that straight to me, why are you calling onCompleted in the onNext block? Why not just using the onCompleted block you left empty ad the bottom?

self.myService.getImage(materialNo: materialNumber).subscribe(
    onNext: { [weak self] imageURL in //I am able to get url here and want to send it to View, following doesn't work
        self?.myImageURL.onNext(imageURL)
        self?.myImageURL.onCompleted()
    },
    onError: { error in },
    onCompleted: { }
)
.disposed(by: disposeBag)