In the context of data binding layout expression, what is the correct syntax for adding a click listener attribute to a button?

The correct syntax for adding a click listener attribute to a button within a data binding layout expression utilizes the ability to define a lambda function that will be executed when the button is clicked. This method allows for cleaner and more manageable code by directly binding UI elements to underlying data or functions in the ViewModel or Fragment.

In this instance, the answer leverages a lambda expression enclosed in curly braces, and the syntax () -> detailFragment.next() defines an anonymous function with no parameters that calls the next() method on the detailFragment. This effectively sets the click listener for the button to trigger the specified function when the button is clicked.

Using the android:onClick attribute indicates that the attribute is intended for capturing click events, making it appropriate for this context, while the lambda syntax allows for defining behaviors in a more functional style.

The other options either do not employ the correct attribute or syntax for setting up a click listener in a data-binding context, leading to potential confusion or errors in implementation.