如何选择2个随机用户在线玩游戏

Question

我在Android Studio中使用tic Tac Toe之类的Kotlin构建了一个应用程序。我有2位玩家，我想在线进行游戏。如何使用Firebase做到这一点？

如果使用Firebase数据库，如何在应用程序中选择2个随机用户进行游戏。

这是我的代码，用于解释2位玩家如何玩游戏：

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
            WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.activity_activiti_2player_5x5)


    playingplayer = PLAYINGPLAYER.FIRST_PLAYER
}



fun ButtonClickes(v: View) {
    val btnselected = v as Button
    var optionNumber = 0

    when (btnselected.id) {
        R.id.btn1 -> optionNumber = 1
        R.id.btn2 -> optionNumber = 2
        R.id.btn3 -> optionNumber = 3
        R.id.btn4 -> optionNumber = 4
        R.id.btn5 -> optionNumber = 5
        R.id.btn6 -> optionNumber = 6
        R.id.btn7 -> optionNumber = 7
        R.id.btn8 -> optionNumber = 8
        R.id.btn9 -> optionNumber = 9
        R.id.btn10 -> optionNumber = 10
    }

    startService(Intent(this@activiti_2player_5x5, SoundButtonService::class.java))


    action(optionNumber, btnselected)
}



fun action(optionNumber: Int, btnselected: Button) {
    if (playingplayer == PLAYINGPLAYER.FIRST_PLAYER) {
        btnselected.setBackgroundResource(R.drawable.button_game_green)
        buttonClicked.add(optionNumber)
        playerOneLastClicked = true
        playingplayer = PLAYINGPLAYER.SECOND_PLAYER
    } else if (playingplayer == PLAYINGPLAYER.SECOND_PLAYER) {
        btnselected.setBackgroundResource(R.drawable.button_game_red)
        buttonClicked.add(optionNumber)
        playerOneLastClicked = false
        playingplayer = PLAYINGPLAYER.FIRST_PLAYER
    }
    imagebtnState()
}