KeyboardEventListener

init in Activity

override fun onResume() {
    super.onResume()
    KeyboardEventListener(this) { isOpen -> // handle event }
}

KeyboardEventListener

fun Activity.getRootView(): View {
    return findViewById(android.R.id.content)
}
fun Context.convertDpToPx(dp: Float): Float {
    return TypedValue.applyDimension(
        TypedValue.COMPLEX_UNIT_DIP,
        dp,
        this.resources.displayMetrics
    )
}
fun Activity.isKeyboardOpen(): Boolean {
    val visibleBounds = Rect()
    this.getRootView().getWindowVisibleDisplayFrame(visibleBounds)
    val contentViewTop = window.findViewById<View>(Window.ID_ANDROID_CONTENT).getTop()

    val heightDiff = getRootView().height - visibleBounds.height()
    val marginOfError = this.convertDpToPx(50F).roundToInt()
    return heightDiff > marginOfError
}

fun Activity.isKeyboardClosed(): Boolean {
    return !this.isKeyboardOpen()
}

KeyboardEventListener (ext)

fun Activity.getRootView(): View {
    return findViewById(android.R.id.content)
}
fun Context.convertDpToPx(dp: Float): Float {
    return TypedValue.applyDimension(
        TypedValue.COMPLEX_UNIT_DIP,
        dp,
        this.resources.displayMetrics
    )
}
fun Activity.isKeyboardOpen(): Boolean {
    val visibleBounds = Rect()
    this.getRootView().getWindowVisibleDisplayFrame(visibleBounds)
    val contentViewTop = window.findViewById<View>(Window.ID_ANDROID_CONTENT).getTop()

    val heightDiff = getRootView().height - visibleBounds.height()
    val marginOfError = this.convertDpToPx(50F).roundToInt()
    return heightDiff > marginOfError
}

fun Activity.isKeyboardClosed(): Boolean {
    return !this.isKeyboardOpen()
}

KeyboardEventListener.kt

import android.view.ViewTreeObserver
import androidx.annotation.CallSuper
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.Lifecycle
import androidx.lifecycle.LifecycleObserver
import androidx.lifecycle.OnLifecycleEvent

class KeyboardEventListener(
    private val activity: AppCompatActivity,
    private val callback: (isOpen: Boolean) -> Unit
) : LifecycleObserver {

    private val listener = object : ViewTreeObserver.OnGlobalLayoutListener {
        private var lastState: Boolean = activity.isKeyboardOpen()

        override fun onGlobalLayout() {
            val isOpen = activity.isKeyboardOpen()
            if (isOpen == lastState) {
                return
            } else {
                dispatchKeyboardEvent(isOpen)
                lastState = isOpen
            }
        }
    }

    init {
        // Dispatch the current state of the keyboard
        dispatchKeyboardEvent(activity.isKeyboardOpen())
        // Make the component lifecycle aware
        activity.lifecycle.addObserver(this)
        registerKeyboardListener()
    }

    private fun registerKeyboardListener() {
        activity.getRootView().viewTreeObserver.addOnGlobalLayoutListener(listener)
    }

    private fun dispatchKeyboardEvent(isOpen: Boolean) {
        when {
            isOpen  -> callback(true)
            !isOpen -> callback(false)
        }
    }

    @OnLifecycleEvent(value = Lifecycle.Event.ON_PAUSE)
    @CallSuper
    fun onLifecyclePause() {
        unregisterKeyboardListener()
    }

    private fun unregisterKeyboardListener() {
        activity.getRootView().viewTreeObserver.removeOnGlobalLayoutListener(listener)
    }
}