Android Kotlin: How to update recyclerView after async call? getting CalledFromWrongThreadException

Question

I am trying to do an async call and then update a RecyclerView. Much like what's outlined in this question: RecyclerView element update + async network call

However, when I try to do this, I get this error: android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.

Here is my code (the main issue is in the setAlbums function):

class AlbumActivity : AppCompatActivity() {

    protected lateinit var adapter: MyRecyclerViewAdapter
    protected lateinit var recyclerView: RecyclerView
    var animalNames = listOf("nothing")

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

        recyclerView = findViewById<RecyclerView>(R.id.rvAnimals)
        recyclerView.layoutManager = LinearLayoutManager(this)
        adapter = MyRecyclerViewAdapter(this, animalNames)
        recyclerView.adapter = adapter

        urlCall("https://rss.itunes.apple.com/api/v1/us/apple-music/coming-soon/all/10/explicit.json")

    }

    private fun urlCall(url: String) {

        val client = OkHttpClient()
        val request = Request.Builder().url(url).build()

        client.newCall(request).enqueue(object : Callback {
            override fun onFailure(call: Call, e: IOException) {}
            override fun onResponse(call: Call, response: Response) = getJSON(response.body()?.string())
        })
    }

    fun getJSON(data: String?) {

        val gson = Gson()
        val allAlbums = ArrayList<Album>()

        val jsonResponse = JSONObject(data)
        val feed = jsonResponse.getJSONObject("feed")
        val albums = feed.getJSONArray("results")

        for (i in 0 until albums.length()) {
            val album = albums.getJSONObject(i)
            allAlbums.add(gson.fromJson(album.toString(), Album::class.java))
        }
        setAlbums(allAlbums)
    }


    fun setAlbums(albums: ArrayList<*>) {

        animalNames = listOf("sue", "betsie")
        adapter.notifyDataSetChanged() // This is where I am telling the adapter the data has changed
    }

    internal inner class Album {
        var artistName: String? = null
        var name: String? = null
    }
}

Does anyone know the issue I am having?

score 3 · Accepted Answer · answered Feb 09 '19 at 20:14

3

You need to execute your wanted code on your main thread like this :

runOnUiThread(new Runnable() {

@Override
public void run() {
    //update your UI
    }
});

answered Feb 09 '19 at 20:14

Tamir Abutbul

7,301
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score 2 · Answer 2 · answered Feb 09 '19 at 20:17

Your Callback functions will be called on a background thread. In part, that is because OkHttp is not an Android-specific library, so it has no idea about Android's main application thread.

You will need to do something to update the UI in the main application thread. Modern options include:

Have your Callback update a MutableLiveData that your UI observes, as then the UI will get updates on the main application thread
Use existing recipes for using OkHttp with RxJava

Android Kotlin: How to update recyclerView after async call? getting CalledFromWrongThreadException

2 Answers2