title: Kotlin - Random numbers without repeating
body: <p>I have a question, how to prevent random numbers from being repeated.
  By the way, can someone explain to me how to sort these random numbers?</p>
  <pre><code>override fun onCreate(savedInstanceState: Bundle?)
      {
          super.onCreate(savedInstanceState)
          setContentView(R.layout.activity_main)
  
          val textView = findViewById&lt;TextView&gt;(R.id.textView)
          val button = findViewById&lt;Button&gt;(R.id.buttom)
  
  
          button.setOnClickListener {
  
              var liczba = List(6){Random.nextInt(1,69)}
              textView.text = liczba.toString()
          }
      }
  </code></pre>