Anyone have any idea why a BindingAdapter is being recognized at compile time as available, but at r...

# android

[locke]

Anyone have any idea why a BindingAdapter is being recognized at compile time as available, but at runtime during view inflation, the adapter is not called?

It's as if the Xml parser is just skipping right over those attributes

[Mark Murphy]

This feels like a better fit for Stack Overflow, but what does your BindingAdapter look like?

https://gitlab.com/commonsguy/cw-andexplore/blob/v0.7/T15-Display/ToDo/app/src/main/java/com/commonsware/todo/BindingAdapters.kt is an example one in Kotlin, which I use at https://gitlab.com/commonsguy/cw-andexplore/blob/v0.7/T15-Display/ToDo/app/src/main/res/layout/todo_display.xml#L64

[locke]

It's a standard Kotlin extension binding. Single argument extended off of View that sets a value on the view

[locke]

Looks functionally identical to yours

[locke]

My initial thought was that extending View rather than a subtype isnt allowed. But I have done so before...

[Mark Murphy]

Extending View should be fine. Anything unusual about the binding expression in the layout? For example, are you not matching on data types for the value?

[locke]

I am not, is that a requirement? I thought you could pass primitives without a data type? The in xml line is:
app:pcuDefault="true"

[Mark Murphy]

Change that to app:pcuDefault="@{true}" and see if that works. It has to be a binding expression with the @{} syntax, as the data binding system ignores ordinary XML attributes. I have not tried a boolean constant as the binding expression, though.

[Will Shelor]

make sure you set your lifecycle observer, too

[Will Shelor]

on the binding

[Mark Murphy]

that only matters if you are binding a LiveData -- in this case, it's a constant

[locke]

Ended up driving and not replying, but @Mark Murphy that both was the challenge and is indeed something you can do. Data binding is perfectly happy with constants passed in like that.

Thank you for the help!