Fullscreen

open class FullScreen : AppCompatActivity() {


    override fun onBackPressed() {
        super.onBackPressed()
        val decorView = window.decorView
        decorView.systemUiVisibility = hideSystemUI()
        window.decorView.viewTreeObserver.addOnGlobalLayoutListener {
            val r = Rect()
            decorView.getWindowVisibleDisplayFrame(r)
            val screenHeight = decorView.rootView.height
            val keypadHeight = screenHeight - r!!.bottom
            decorView.isFocusableInTouchMode = true
            decorView.requestFocus()


            Log.d("keypadHeight", "keypadHeight = $keypadHeight, ${screenHeight * 0.15}")
            if (keypadHeight > screenHeight * 0.15) {
                showSystemUI()
                hideKeyboardFrom(this, window.decorView)
            } else {

                onBackPressed()
                decorView.setOnSystemUiVisibilityChangeListener { visibility ->
                    if (visibility == 0) {
                        decorView.systemUiVisibility = hideSystemUI()
                    }
                }
            }
        }
    }


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);

        fullScreenActivity()

    }

    fun fullScreenActivity() {
        val decorView = window.decorView

        decorView.systemUiVisibility = hideSystemUI()

        decorView.viewTreeObserver.addOnGlobalLayoutListener {
            val r = Rect()
            decorView.getWindowVisibleDisplayFrame(r)
            val screenHeight = decorView.rootView.height


            val keypadHeight = screenHeight - r!!.bottom

            Log.d("keypadHeight", "keypadHeight = $keypadHeight, ${screenHeight * 0.15}")
            if (keypadHeight > screenHeight * 0.15) { // 0.15 ratio is perhaps enough to determine keypad height.

                decorView.systemUiVisibility = showSystemUI()


            } else {

                decorView.systemUiVisibility = hideSystemUI()

            }
        }
    }



    fun showKeyboardFrom(context: Context, view: View) {
        val imm: InputMethodManager =
            context.getSystemService(INPUT_METHOD_SERVICE) as InputMethodManager
        imm.showSoftInputFromInputMethod(view.windowToken, 0)
    }

    fun hideKeyboardFrom(context: Context, view: View) {
        val imm: InputMethodManager =
            context.getSystemService(INPUT_METHOD_SERVICE) as InputMethodManager
        imm.hideSoftInputFromWindow(view.windowToken, 0)
    }

    fun showSystemUI(): Int {
        return (View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                or View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                or View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN)

    }

    fun hideSystemUI(): Int {
        return (View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                or View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                or View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                or View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                or View.SYSTEM_UI_FLAG_FULLSCREEN
                or View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY)
    }
}