UiStateBindingAdapters.kt

@BindingAdapter("uiState")
fun setUiStateForLoading(progressView: ProgressBar, uiState: UIState) {
  progressView.visibility = when (uiState) {
    Loading -> View.VISIBLE
    else -> View.GONE
  }
}

@BindingAdapter("uiState")
fun setUiStateForLoadedContent(view: View, uiState: UIState) {
  view.visibility = when (uiState) {
    HasData -> View.VISIBLE
    else -> View.GONE
  }
}

@BindingAdapter("emptyState")
fun setUiStateForEmptyView(view: View, uiState: UIState) {
  view.visibility = when (uiState) {
    NoData -> View.VISIBLE
    else -> View.GONE
  }
}

@BindingAdapter("errorState")
fun setUiStateForErrorView(view: View, uiState: UIState) {
  view.visibility = when (uiState) {
    is Error -> View.VISIBLE
    else -> View.GONE
  }
}

@BindingAdapter("errorTextState")
fun setUiStateForErrorText(textView: TextView, uiState: UIState) {
  val textState = when (uiState) {
    is Error -> textView.context.getString(uiState.errorMsgId) to View.VISIBLE
    else -> EMPTY_STRING to View.GONE
    
  }

  textView.text = textState.first
  textView.visibility = textState.second
}

UiStates.kt

/**
 * Base class to represent common UI states
 */
sealed class UIState

/**
 * the screen is currently loading it's data. "loading state"
 */
object Loading : UIState()

/**
 * data was successfully loaded for the screen.  "happy path"
 */
object HasData : UIState()

/**
 * the load was successful, but there was no data.  "empty state"
 */
object NoData : UIState()

/**
 * some type of error occurred.  "error state"
 */
class Error(@StringRes val errorMsgId:Int = 0) : UIState()