Kotlin: How to change values of MutableLiveData in ViewModel without using getters and setters

Here is my viewmodel:

class MyProfileEditSharedViewModel : ViewModel() {
    val question = MutableLiveData<String>()
    val answer = MutableLiveData<String>()

    fun setQuestion (q: String) {
        question.value = q
    }

    fun setAnswer (a: String) {
        answer.value = a
    }
}

I set the data using setQuestion and setAnswer like this:

viewModel.setQuestion(currentUserInList.question)
viewModel.setAnswer(currentUserInList.answer)

I try to get question and answer from the ViewModel like this:

val qnaQuestionData = communicationViewModel.question as String
val qnaAnswerData = communicationViewModel.answer as String

Compiler says I cannot cast MutableLiveData to string. Should I make a separate getter like my setter? I heard that you don't need to use getters and setters in kotlin, is there anyway to edit val question and val answer in my viewmodel without using getters and setters?

Thank you!!

Solution

You can't cast it to String because the type of object is MutableLiveData, but you can access the value with .value property

val qnaQuestionData = communicationViewModel.question.value
val qnaAnswerData = communicationViewModel.answer.value

in this case, may facing errors about MutableLiveData initialization.

another way is observing the LiveData for changes:

communicationViewModel.question.observe(this, Observer{ data->
 ...
})

Or if you have not accessed to any lifecycle owner

communicationViewModel.question.observeForever(Observer{ data->
 ...
})

but please remember to remove the observer through removeObserver method

for setting the values it's better to use properties directly or binding way

communicationViewModel.question.postValue("some new value")

communicationViewModel.question.value = "some new value"

Suggestion for MutableLiveData properties:

val question: MutableLiveData<String> by lazy { MutableLiveData<String>() }
val answer: MutableLiveData<String> by lazy { MutableLiveData<String>() }

https://developer.android.com/reference/android/arch/lifecycle/LiveData