MVVM - Removing Logic from Your Views with BindingAdapters

CustomBindingAdapters.kt

@BindingAdapter(“isVisible”)
fun setIsVisible(view: View, isVisible: Boolean) {
	if (isVislble) { 
		view.visibility = View.VISIBLE
	} else {
		view.visibility = View.GONE
	}
}

CustomBindingAdatpersTest.kt

class CustomBindingAdatpersTest {

    @Test
    fun isVisibleShouldBeEasilyControlledWithABoolean() {
        val v = View(InstrumentationRegistry.getTargetContext())
        setIsVisible(v, true) // visible
        assertThat(v.visibility).isEqualTo(View.VISIBLE)

        setIsVisible(v, false) // gone
        assertThat(v.visibility).isEqualTo(View.GONE)
    } 
  
}

example_layout.xml

<TextView 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:visibility="@{post.hasComments ? View.Visible : View.Gone}" />

updated_example_layout.xml

<TextView 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    app:isVisible="@{post.hasComments()}" />