Android Event Listener Data Binding for ViewPager

Question

Is it possible to bind a handler for setOnPageChangeListener to a ViewPager in XML file with the Android Binding functionality?

The demos show onClick events but I

Answer 1

Instead of OnPageChangeListener, you can use SimpleOnPageChangeListener and only override the method you're interested in:

@BindingAdapter("onPageChanged")
@JvmStatic
fun addPageChangedListener(viewPager: ViewPager, listener: OnPageChanged) {
    viewPager.addOnPageChangeListener(object : ViewPager.SimpleOnPageChangeListener() {
        override fun onPageSelected(position: Int) {
            listener.onPageChanged(position)
        }
    })
}

interface OnPageChanged {
    fun onPageChanged(position: Int)
}

Layout:

Handler:

fun handlePageChanged(position: Int) {
    println("Page changed: $position")
}

As others have pointed out, you may want to be careful not to attach duplicate listeners.