CODEWITHSUNDEEP
androidsqlite
user2162383
user2162383

Reputation:

Error in simple AsyncTask

In my android app, I am trying to make use of ASYNC Task ... whenever I set text of any TextView of EditText in doInBackground(...) .... I get an error , but when I set the same in onCreate , it works .. :( here is the code :

public class RemoteFiles extends Activity {



EditText etrmm ;
TextView t;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_remote_files);
    initVars();         
    new ConnectToServer().execute(null);



}
protected void initVars(){
    etrmm =(EditText)findViewById(R.id.etRM);
    etrmm.setText("UnSET");
    t=(TextView)findViewById(R.id.RM);
    t.setText("UnsET");
}
public class ConnectToServer extends AsyncTask<String, Integer, Void> {

    //private ProgressDialog pd = new ProgressDialog(RemoteFiles.this);
    private ProgressDialog pdd ;
    @Override
    protected Void doInBackground(String... params) {
        // TODO Auto-generated method stub

        for(int i=0;i<20;i++){
            publishProgress(5);
            try {
                Thread.sleep(88);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

        etrmm.setText("Edittext SET");

        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);
        pdd.dismiss();

    }

    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub
        super.onPreExecute();
        // pd.setMessage("Connecting to server... ");
        // pd.show();

        pdd = new ProgressDialog(RemoteFiles.this);
        pdd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        pdd.setMax(100);
        pdd.show();




    }

    @Override
    protected void onProgressUpdate(Integer... values) {
        // TODO Auto-generated method stub
        super.onProgressUpdate(values);
        pdd.incrementProgressBy(values[0]);

    }

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_remote_files, menu);
    return true;
}}

here is the layout :

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<TextView
    android:id="@+id/RM"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"

    android:padding="@dimen/padding_medium"
    android:text="@string/hello_world"
    tools:context=".RemoteFiles" />

<EditText
    android:id="@+id/etRM"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:ems="10" >

    <requestFocus />
</EditText>

logcat says android.view.ViewRoot$CalledFromWrongThreadException

Upvotes: 0

Views: 419

Answers (3)

Raghunandan
Raghunandan

Reputation: 133560

AsyncTask's onpreExecute and onPostExecute methods run o UI Thread. You can make changes to the UI here. doInBackground does not run on UI thread. It is used to do long Running operations. Runs in the background thread. You cannot update ui from the background thread in doinBackground.

Set text in textview in onPostExecute method of asynctask.

The document in the developer site has detailed information regarding the topic under the heading THE 4 STEPS. http://developer.android.com/reference/android/os/AsyncTask.html

Upvotes: 0

Pragnani
Pragnani

Reputation: 20155

doInBackground(String... params) not run on UI Thread, so you can't set text for edittext there

if you want to set edittext value, return the value in doInBackGround and use the parameter value in onPostExecute and set it in onPostExecute()

Upvotes: 1

codeMagic
codeMagic

Reputation: 44571

You can't do UI stuff in doInBackground(). This should be done in any of the other methods. For your purposes, probably onPostExecture()

Take a look at the AsyncDocs, doInBackground() doesn't run on the main (UI) thread

Upvotes: 0

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