FragmentSoftInputCorrector changes a soft input type of activity for a single fragment that requires SOFT_INPUT_ADJUST_RESIZE during it is attached to this activity

FragmentSoftInputCorrector.kt

/**
 * FragmentSoftInputCorrector changes a soft input type of activity
 * for a single fragment that requires SOFT_INPUT_ADJUST_RESIZE
 * during it is attached to this activity
 *
 * Usage inside a fragment:
 *
 *  override fun onAttach(context: Context) {
 *      super.onAttach(context)
 *      FragmentSoftInputCorrector(activity!!, this)
 *  }
 */
class FragmentSoftInputCorrector @Inject constructor(
        private val activity: FragmentActivity,
        private val fragment: Fragment) : LifecycleObserver {

    private var originalSoftInputMode: Int? = null

    init {
        fragment.lifecycle.addObserver(this)
    }

    @OnLifecycleEvent(Lifecycle.Event.ON_CREATE)
    fun replaceSoftInput() {
        originalSoftInputMode = activity.window?.attributes?.softInputMode
        activity.window?.setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE)
    }

    @OnLifecycleEvent(Lifecycle.Event.ON_DESTROY)
    fun restoreSoftInput() {
        originalSoftInputMode?.let { activity.window?.setSoftInputMode(it) }
        fragment.lifecycle.removeObserver(this)
    }
}