How to hide bottom navigation bar in android studio

Question

private fun hideNavigation() {
    window.decorView.apply {
        // Hide both the navigation bar and the status bar.
        // SYSTEM_UI_FLAG_FULLSCREEN is only available on Android 4.1 and higher, but as
        // a general rule, you should design your app to hide the status bar whenever you
        // hide the navigation bar.
        systemUiVisibility = View.SYSTEM_UI_FLAG_HIDE_NAVIGATION or View.SYSTEM_UI_FLAG_FULLSCREEN
    }
}

I'm calling this function in the onCreate() function. But, once I click on anywhere in the screen, it appears again, any fixes?