How to pass data variable to included layout?

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Is there a way to pass data variable to included layout?

parent layout

<?xml version="1.0" encoding="utf-8"?>
<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"
    tools:showIn="@layout/fragment_settings">

    <data>

        <variable
            name="viewModel"
            type="......settings.SettingsFragmentViewModel" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:id="@+id/content"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:animateLayoutChanges="true"
        android:overScrollMode="never"
        android:padding="@dimen/spacing_default">

        <include
            android:id="@+id/main"
            layout="@layout/layout_settings_main" />

    </androidx.constraintlayout.widget.ConstraintLayout>

and want to have viewModel in included layout

<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"
    tools:showIn="@layout/fragment_settings">

    <data>

        <variable
            name="viewModel"
            type="......settings.SettingsFragmentViewModel" />
    </data>

    <merge>
...........

or is it possible only when setting like this:

 binding = FragmentSettingsBinding.inflate(inflater, container, false).apply {
            lifecycleOwner = this@SettingsFragment
            viewModel = this@SettingsFragment.viewModel
            main.viewModel = this@SettingsFragment.viewModel
        }
3 Answers

In parent xml inside include tag pass data variable to included layout using bind:viewModel.

<?xml version="1.0" encoding="utf-8"?>
<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"
xmlns:bind="http://schemas.android.com/apk/res-auto"
tools:showIn="@layout/fragment_settings">

<data>

    <variable
        name="viewModel"
        type="......settings.SettingsFragmentViewModel" />
</data>

<androidx.constraintlayout.widget.ConstraintLayout
    android:id="@+id/content"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:animateLayoutChanges="true"
    android:overScrollMode="never"
    android:padding="@dimen/spacing_default">

    <include
        android:id="@+id/main"
        layout="@layout/layout_settings_main"
        bind:viewModel="@{viewModel}" />

</androidx.constraintlayout.widget.ConstraintLayout>

Your included layout will get object instance in viewModel.

For more details check this tutorial

Ok so, at the beginning of this article I’ve said that it depends whether it’s possible to pass the variable to a secondary layout or not. The reason for this is the following: Data binding does not support include as a direct child of a merge element. For example, the following layout is not supported:

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:bind="http://schemas.android.com/apk/res-auto">
   <data>
       <variable name="user" type="it.communikein.myunimib.User"/>
   </data>
   <merge>
       <include layout="@layout/name"
           bind:user="@{user}"/>
       <include layout="@layout/contact"
           bind:user="@{user}"/>
   </merge>
</layout>

Open build.grade and add dataBinding { enabled = true } in block android{ // ...}

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