Android, kotlin, hide status bar, ステータスバーを隠す

 ** under SDK 16

if (Build.VERSION.SDK_INT < 16) {
            window.setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                    WindowManager.LayoutParams.FLAG_FULLSCREEN)
        }

** SDK 16 and upper

window.decorView.systemUiVisibility = View.SYSTEM_UI_FLAG_FULLSCREEN
actionBar?.hide()

ref : https://developer.android.com/training/system-ui/status?hl=en