Hey so I am trying to use the `androidx.lifecycle.observe` ktx extension. When I do `viewModel.obser...

# android

[adams2]

Hey so I am trying to use the androidx.lifecycle.observe ktx extension. When I do viewModel.observe(this, ::myOnChanged), I get this error: Type mismatch: inferred type is KFunction1<Action, Unit?> but Observer<in Action!> was expected. However, when I do viewModel.observe(this) { myOnChanged(it) }, the extension functions as expected. Is there some precedence rule preventing me from using a method reference?

[Anas Tariq]

@adams2 the second parameter should be an Observer you can do something like.

val observer = Observer<MyObject> { myObject -> 
  myOnChanged(myObject)
}

viewModel.observe(this, observer)

[Kit]

U didn't import

[Kit]

@Anas Tariq he is trying to use the ktx here to get rid of the exact Observer thing lol

[Travis]

Your myOnChanged fun is probably written as an expression that returns a nullable like action?.let { /* do something */ } so it's having trouble SAM converting to an Observer. Try either explicitly returning Unit from myOnChanged or just defining the function without the expression since you're trying to return Unit anyway.

[adams2]

aha it was indeed returning Unit? and not Unit