Pass data from repository to View Model without any third-party

Question

I want to return the data from the repository to the viewmodel without using any third-party

    class MyRepository{
        
    // Some code that return the data from webservice
        
}


class MyViewModel:ViewModel(){
    
init{
    val repo= MyRepository()
    MyRepository.getData()
}
    
    //I need a way to operate on the data that I get from repository
    
    }

ViewModel call -> Repoistory get the data-> ViewModel do operation on the data

With no third-parties library .. just the android studio SDK.

Answer 1

You can use callbacks to be notified when a work is done. The way to do it would be to pass the view model as a parameter to the method that will perform the work. I recommend you to define an interface so the repository does not rely directly on the view model but rather an interface.

The solution would look something like:

interface WebServiceCallback {
    fun onWebServiceSuccess(data: MyObject)
    fun onWebServiceError(error: MyError)
}

class MyViewModel: ViewModel(), WebServiceCallback {

    init {
        val repo = MyRepository()
        repo.getData(this)
    }

    override fun onWebServiceSuccess(data: MyObject) {
        //Implementation of what to do on success
    }

    override fun onWebServiceError(error: MyError) {
        //Implementation of what to do on failure
    }
}

class MyRepository { 
    fun getData(callback: WebServiceCallback) {
        //Do your service call however you have implemented it
        if(serviceResponse.isSuccess() == true) {
            callback.onWebServiceSuccess(serviceResponse.data)
        } else {
            callback.onWebServiceError(serviceResponse.error)
        }
    }
}
    

This solution will call the respective methods on the view model after you have completed the work on the repo. Hope this answer it's helpful to you.