Unknown class: java.lang.String in AndroidX two-way data binding

Question

Just migrated to AndroidX and this error has appeared when trying to build: Unknown class: java.lang.String file://----/app/src/main/res/layout/my_fragment.xml Line:XXX

The line in question is the start of an EditText which uses two-way databinding: android:text="@={viewModel.myString}"

myString looks like this:

val myString = MutableLiveData<String>()

I have multiple instances of this; each one involves two-way data binding in an EditText with a LiveData<String>.

Answer 1

For those having this issue with databinding v3.4.0, a temporary rollback to 3.3.2 fixed it for me. I posted an issue about this on their tracker in the meantime.

To rollback, all you have to do is change your build.gradle accordingly:

android {
    ...
        dataBinding {
            enabled = true
            version = '3.3.2'
        }
    ...
}