Custom View setter 이용

01_RoundImageView.kt

class RoundImageView : ImageView {
  
  private radious : Int
  
  fun setRadious(rad : Int) {
    this.radious = rad
  }
  // 이하 생략
}

02_MainViewModel.kt

class MainViewModel {
  val imageRadious = ObservableInt()
  
  init {
    imageRadious.set(10)
  }
}

03_main.xml

<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="vm"
            type="MainViewModel"
            />

    </data>
<custom.RoundImageView
    android:layout_width="50dp"
    android:layout_height="50dp"
    app:radious="@{vm.imageRadious}"
    />
/layout>