How to solve the error : Only the original thread that created a view hierarchy can touch its views

问题

I'm not really familiar with the concept of threads , but I got this error showing up each time I'm trying to display my RecyclerView : Only the original thread that created a view hierarchy can touch its views. I'm retrieving data regarding some clients from the server , putting in it in an ArrayList and then displaying the data within a recyclerView .

The data is retrieved within the method doInBackGround()

Here is my Code :

ClientList.java :

public class ClientList extends AppCompatActivity {

    private ClientAdapter clientAdapter;
    private RecyclerView recyclerView;

    List<Client> clientList;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_client_list);
        clientList= new ArrayList<>();
        recyclerView=findViewById(R.id.client_list_recycler);
        ConnectionOdoo tarea;
        tarea = new ConnectionOdoo();
        tarea.execute();
    }

    private class ConnectionOdoo  extends AsyncTask<Void, String, Boolean> {
        @Override
        protected Boolean doInBackground(Void... params) {

            // Try connection to server
            ConnectionToServer oc = ConnectionToServer.connect(Url, Port, DataBase, Username, Passwort);
           /* Object[] param = {new Object[0]};
            Integer ids = oc.search_count("product.template", param);
            System.out.println("Num. of customers: " + ids.toString() + "\n");*/
            Object[] param = {new Object[]{
                    new Object[]{"customer", "=", true},
                    new Object[]{"is_company", "=", false}}};

            List<HashMap<String, Object>> data = oc.search_read("res.partner", param, "name", "id");

            String msgResult = "";
            for (int i = 0; i < data.size(); ++i) {

                Log.i("NAMES ", data.get(i).get("name")+"");
                clientList.add(new Client(data.get(i).get("name")+"") );
            }


            clientAdapter=new ClientAdapter(clientList, ClientList.this);

            RecyclerView.LayoutManager layoutManager= new LinearLayoutManager(ClientList.this);

            **recyclerView.setLayoutManager(layoutManager);**

            recyclerView.setAdapter(clientAdapter);

            return false;
        }
    }
}

The line in between ** ** is the line that causes an error .

Here is the log :

    Process: com.example.tarik.gestion, PID: 9642
    java.lang.RuntimeException: An error occured while executing doInBackground()
        at android.os.AsyncTask$3.done(AsyncTask.java:304)
        at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
        at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
        at java.util.concurrent.FutureTask.run(FutureTask.java:242)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
        at java.lang.Thread.run(Thread.java:818)
     Caused by: android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
        at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:7665)
        at android.view.ViewRootImpl.requestLayout(ViewRootImpl.java:1119)
        at android.view.View.requestLayout(View.java:18855)
        at android.view.View.requestLayout(View.java:18855)
        at android.view.View.requestLayout(View.java:18855)
        at android.view.View.requestLayout(View.java:18855)
        at android.view.View.requestLayout(View.java:18855)
        at android.view.View.requestLayout(View.java:18855)
        at android.support.constraint.ConstraintLayout.requestLayout(ConstraintLayout.java:3172)
        at android.view.View.requestLayout(View.java:18855)
        at android.support.v7.widget.RecyclerView.requestLayout(RecyclerView.java:4202)
        at android.view.ViewGroup.removeAllViews(ViewGroup.java:4688)
        at android.support.v7.widget.RecyclerView$5.removeAllViews(RecyclerView.java:900)
        at android.support.v7.widget.ChildHelper.removeAllViewsUnfiltered(ChildHelper.java:193)
        at android.support.v7.widget.RecyclerView.setLayoutManager(RecyclerView.java:1334)
        at com.example.tarik.gestion.ClientList$ConnectionOdoo.doInBackground(ClientList.java:64)
        at com.example.tarik.gestion.ClientList$ConnectionOdoo.doInBackground(ClientList.java:37)
        at android.os.AsyncTask$2.call(AsyncTask.java:292)
        at java.util.concurrent.FutureTask.run(FutureTask.java:237)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231) 
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 
        at java.lang.Thread.run(Thread.java:818) 

回答1:

You need to put your code that updates the UI in the UI thread:

runOnUiThread(new Runnable() {
@Override
public void run() {
    //your code here to update UI    
    }
});

来源：https://stackoverflow.com/questions/56917814/how-to-solve-the-error-only-the-original-thread-that-created-a-view-hierarchy