I am making an Android app to get the posts from my University using Kotlin. For now I have a button to refresh the page manually and a drop-down menu from which I can choose the period of time for refreshing the page and getting the data. I am using Jsoup to get the data and then I split the data and make it an Array. I want an email to be sent, or a notification which would be better if something changes.

class MainActivity : AppCompatActivity(){

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    lateinit var refresh: Runnable
    val handler10 = Handler()

    spinnerVrijeme.onItemSelectedListener = object : AdapterView.OnItemSelectedListener {

        override fun onItemSelected(adapterView: AdapterView<*>?, view: View?, position: Int, id: Long) {

            if(adapterView?.getItemAtPosition(position).toString()=="10 minutes")
            {
                Toast.makeText(this@MainActivity, "You chose${adapterView?.getItemAtPosition(position).toString()}",
                    Toast.LENGTH_LONG).show()

                refresh = Runnable { // Do something
                    getHtmlFromWeb()
                    handler10.postDelayed(refresh, 1000*60*10)
                    clearTextView()
                }
                handler10.post(refresh)
            }
     button_click.setOnClickListener()
        {
           // your code to perform when the user clicks on the button
           //Toast.makeText(this@MainActivity, "Page Loading...", Toast.LENGTH_SHORT).show()
           getHtmlFromWeb()
        }

And then I have a function to get the data from the website:

 @SuppressLint("SetTextI18n")
public fun getHtmlFromWeb() {

    val executor: ExecutorService = Executors.newSingleThreadExecutor()
    val handler = Handler(Looper.getMainLooper())


    executor.execute(Runnable {
        //Background work here
        val doc = Jsoup.connect("websiteURL").get()

        val smjer = doc.select("div.col-md-6.col-lg-12 > *").text()
        val smjer_cleaned = Jsoup.clean(smjer, "", Whitelist.none(), Document.OutputSettings().prettyPrint(false))

        val split_all = smjer_cleaned.split("  ").toTypedArray()

        var split_all_copy = split_all.copyOf()

        handler.post(Runnable {
            //UI Thread work here
            for(i in 0..split_all.size - 1){
                PrikazStranice.append(split_all.elementAt(i)   "\n\n")
            }
            PrikazStranice.movementMethod = ScrollingMovementMethod()

            fun WebsiteChanged (){

                for (i in 0..split_all.size-1)
                {
                    if(split_all_copy.elementAt(i) != split_all.elementAt(i))
                    {
                        //Do something
               
                       //Store the new Array<String>
                       split_all.elementAt(i) = split_all_copy.elementAt(i)
                    }
                }
            }
        })
    })
}

So, for now I can manually press the button and the posts will be shown in TextView, but I would like to automate it so the change will be recognized. I was thinking that I have to call the WebsiteChange() function where I refresh the page every 10 minutes for example, and there, catch the new String Array which I would compare to the original one, and then give the original one the new value. Right now, I don't have an idea how I could make a function WebsiteChange() outside of getHtmlFromWeb() and get the original String Array from there and use it in the right way. I just picked up on Kotlin and Android apps development, so any suggestion is welcome.

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