iOS - MVVM Data Binding-CodePudding

I am working with MVVM design architecture, I have gone through multiple articles about data binding. We can achieve data binding through Protocol, Closure, and Third Party(like RxSwift). So, if I am wrong please correct me otherwise let me know "how many ways to bind the data in iOS(Swift) MVVM design architecture?"

CodePudding user response：

Beside what you mentioned you can also use Combine framework and "Boxing" - observable objects

CodePudding user response：

The easiest one is by using Observable class binding known as Boxing. create an Observable class:

class Observable<T> {

var value: T? {
    didSet {
        DispatchQueue.main.async {
            self.listener?(self.value)
        }
    }
}

init( _ value: T?) {
    self.value = value
}

private var listener: ((T?) -> Void)?

func bind(_ listener: @escaping (T?) -> Void) {
    listener(value)
    self.listener = listener
}
}

in your viewModel define it in this way: (this is a sample for showing loader in your view controller)

var isLoadingData: Observable<Bool> = Observable(false)

Because the Observable class is a generic type, you can pass other types to it.

in your view model you can set the value:

isLoadingData.value = true

then in your view controller use something like this:

   viewModel.isLoadingData.bind { [weak self] loading in
        guard let loading = loading, let self = self else {
            return
        }
        DispatchQueue.main.async {
            if loading {
                //Show a loader
            } else {
                //Hide a loader
            }
        }
    }

As soon as a value is assigned to the isLoadingData object, it will trigger your view controller. We have to use [Weak self] to avoid strong references.