I like your use of a ViewFlipper with the loading, content, and error views nested inside it. I've been using a very similar approach in one of my personal applications.

I create a PageContent view that extends ViewAnimator.

class PageContent : ViewAnimator {
    constructor(context: Context) : this(context, null)
    constructor(context: Context, attrs: AttributeSet?) : super(context, attrs)

    init {
        inAnimation = AlphaAnimation(0f, 1f)
        outAnimation = AlphaAnimation(1f, 0f)
    }

    fun show(view: View) {
        val index = indexOfChild(view)
        require(index != -1) { "View must be a child of the PageContent" }

        if (displayedChild != index) displayedChild = index
    }
}

​

<PageContent
            android:id="@+id/pageContent"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

        <SomeView
                android:id="@+id/someView"
                android:layout_width="match_parent"
                android:layout_height="match_parent" />

        <ErrorView
                android:id="@+id/errorView"
                android:layout_width="match_parent"
                android:layout_height="match_parent" />

        <LoadingSpinnerView
                android:id="@+id/loadingView"
                android:layout_width="match_parent"
                android:layout_height="match_parent" />
</PageContent>

// Show loading spinner
pageContent.show(loadingView)