Lets MVVM activity_main.xml

<layout>
    <data>
        <variable
            name="viewModel"
            type="com.thebotbox.letsmvvm.presentation.viewmodel.MainViewModel" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout 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"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".presentation.activity.MainActivity">

        <TextView
            android:id="@+id/quote"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:gravity="center"
            android:textColor="@android:color/black"
            app:layout_constraintDimensionRatio="W,1:1"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <Button
            android:id="@+id/fetchQuote"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:onClick="@{_->viewModel.fetchQuoteFromServer()}"
            android:text="@string/fetch_quote"
            app:layout_constraintBottom_toTopOf="@id/addToDb"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent" />

        <Button
            android:id="@+id/addToDb"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:onClick="@{_->viewModel.addQuoteToDB()}"
            android:text="@string/save_to_db"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent" />

    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>