Databind Includes Layout

Question

Trying to dynamically set the layout using databinding but I can't seem to get the ternary operator to work right. Must be missing escape character or something.

<include
    android:id="@+id/setting"
    bind:settingsViewModel="@{settingsViewModel}"
    layout="@{settingsViewModel.configFlag ? @layout/settings_v1 :@layout/settings_v2}" />

Seems simple enough but errors with "****/ data binding error ****msg:included value ... must start with @layout/. "

Answer 1

The answer to this is that you cannot do this. Layout is called before and so this logic cannot be done before hand.

Answer 2

You can only solve this by including multiple files and toggling the visibility respectively based on your value you want to bind. An example can be found here: https://stackoverflow.com/a/43289414/11544951 This example uses ViewStubs, but include-tags work just the same way.

So you'd basically do:

<include
layout="@layout/layout_A"
android:visibility="@{viewModel.condition? View.VISIBLE : View.GONE}"
/>

<include
layout="@layout/layout_B"
android:visibility="@{!viewModel.condition? View.VISIBLE : View.GONE}"
/>

This works fine, if the viewmodel for both layouts is the same. If it isn't, check out my solution to this issue: How can I include one layout in another only, if the viewmodel is of a certain subtype with databinding? It shows how to check whether a viewmodel is of a specific type and how to only bind it, if it is.