is a bad practice expose the Activity in the XML layout in a MVVM app?

Question

The general idea is that the XML Layout have a reference to the ViewModel like this:

<?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"
    android:id="@+id/layout">

    <data>
        <variable
            name="aboutViewModel"
            type="com.app.about.AboutActivity" />
    </data>

The question is that if is a bad practique expose too the activity like this:

<?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"
    android:id="@+id/layout">

    <data>
        <variable
            name="aboutActivity"
            type="com.app.about.AboutActivity" />

    </data>

Because sometimes I only need call functions for open or close the activity, and I think that these are not a reason enough to create a new ViewModel.

Thanks

Answer 1

If you follow the OOB - separation of concerns then you shouldn't tightly couple the VM with Activity. Also you don't have to create an new VM or to tightly couple your current VM, you can just access the activity/context like this:

android:onClick="@{(view)->((Activity)(view.getContext()))}"