Learning Concurrency in Kotlin

A synchronous function wrapped in an asynchronous caller

The first approach is quite simple. We can create a loadNews() function that directly invokes fetchRssHeadlines() and displays its results in the same way we did before:

private fun loadNews(){  val headlines = fetchRssHeadlines()  val newsCount = findViewById<TextView>(R.id.newsCount)  launch(UI) {    newsCount.text = "Found ${headlines.size} News"  }}

Notice that this function is synchronous, and will call fetchRssHeadlines() in the same thread that it's called. Consider this code, for example:

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

Doing this will result in a NetworkOnMainThreadException ...