ObservableField vs. LiveData

adapter.kt

class Adapter(list: ArrayList<String>) : RecyclerView.ViewHolder(binding.root) {

    // 02. using observablefield
    // variable binding is your item.xml, generated into -> ItemBinding
    lateinit val binding: ItemBinding // this should be defined on your project.
    fun changeVariableA(msg: String) {
        binding.apply {
            message = msg
            executePendingBindings() // directly tells the binding to be updated, without delay
        }
    }
}

fragment.kt

// fragment.kt
class Fragment : Fragment() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        // ...

        // trigger this on your cases 01. livedata
        viewModel.obsField.observe { msg ->
            // listen changes and update the adapter variable
            adapter.changeVariableA(msg)
        }
        viewModel.changeObs("abc")

        // or trigger/call/invokes this on your cases directly 02. observablefield
        adapter.changeVariableA(msg)
    }
}

item.xml

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools">

    <data>

        <variable
            name="message"
            type="String"/>
    </data>


    <TextView
        android:id="@+id/tvMsg"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@{message}"/>

</layout>

viewmodel.kt

// viewmodel.kt
class VM : ViewModel() {
    // 01. LiveData
    // private backing field, encapsulate the setter from outside class
    private val _obsField = LiveEvent<String>()
    val obsField: LiveData<String>
        get() = _obsField

    fun changeObs(msg: String) {
        _obsField.value = msg
        newObsField.set(msg)
    }
    

    // 02. using observablefield
    val newObsField = ObservableField<String>("test")
}