Android : Network on main thread exception even when using AsyncTask

Question

I am working on an Android project and for Login I am communicating with the server for authentication. Even though I am using AsyncTask, I am getting NetworkOnMain thread exception. Why is that. Here is my code :

public class Login extends Activity {

    public static RestTemplate rest = new RestTemplate();
    Button loginButton = (Button) findViewById(R.id.LoginButton);
        loginButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!(v == null)) {
                    EditText userEmail = (EditText) findViewById(R.id.usernameText);
                    EditText userPassword = (EditText) findViewById(R.id.PasswordField);
                    if (!(userEmail.getText().toString().isEmpty())) {
                        if (!(userPassword.getText().toString().isEmpty())) {
                            loginUserViaRest(userEmail.getText().toString(), userPassword.getText().toString());
                            if (!(StaticRestTemplate.jsessionid == null)) {
                                if (!(StaticRestTemplate.jsessionid.isEmpty())) {

                                    executeRestLogin executeRestLogin = new executeRestLogin();
                                    executeRestLogin.doInBackground();

 private class executeRestLogin extends AsyncTask<Void,Void,Void>{

        @Override
        protected Void doInBackground(Void... params) {
            HttpHeaders requestHeaders = new HttpHeaders();
            requestHeaders.add("Cookie", "JSESSIONID=" + StaticRestTemplate.jsessionid);
            HttpEntity<String> requestEntity = new HttpEntity<>(requestHeaders);

// Below line gives me an error
            HttpEntity<String> rssResponse = rest.exchange(
                    "http://192.168.178.60:8080/dashboard",
                    HttpMethod.GET,
                    requestEntity,
                    String.class);
            StaticRestTemplate.jsessionid = rssResponse.getBody();
            return null;
        }
    }

What am I doing wrong. Also, how can I get custom objects back as response from async task?

Update

To the next problem in question :

  ExecuteRestLogin executeRestLogin = new ExecuteRestLogin();
// The below execute method works, but I cannot get the result of postExecute in it, it shows me its not of the type Void, Void, String. 
 String result =  executeRestLogin.execute();

private class ExecuteRestLogin extends AsyncTask<Void,Void,String>{

        @Override
        protected String doInBackground(Void... params) {
            HttpHeaders requestHeaders = new HttpHeaders();
            requestHeaders.add("Cookie", "JSESSIONID=" + StaticRestTemplate.jsessionid);
            HttpEntity<String> requestEntity = new HttpEntity<>(requestHeaders);

            HttpEntity<String> rssResponse = rest.exchange(
                    "http://192.168.178.60:8080/dashboard",
                    HttpMethod.GET,
                    requestEntity,
                    String.class);
            StaticRestTemplate.jsessionid = rssResponse.getBody();
            return StaticRestTemplate.jsessionid;
        }

        @Override
        protected void onPostExecute(String aVoid) {
            super.onPostExecute(aVoid);
        }
    }

Implement `onPostExecute(.... )`.. refer this [tutorial](http://programmerguru.com/android-tutorial/android-asynctask-example/) — M D, Jul 15 '15 at 12:37

score 1 · Answer 1 · answered Jul 15 '15 at 12:37

1

executeRestLogin.doInBackground();

Call execute() to execute an async task on a background thread. Calling doInBackground() directly just runs the method on your current thread.

how can I get custom objects back as response from async task

Put the code that deals with async task results in onPostExecute(). It gets run on the UI thread.

answered Jul 15 '15 at 12:37

laalto

150,114
66
286
303

So I have to create a new thread like Thread thread = new Thread(new Runnable( ) ), and inside this call the doInBackground method, but then I can call the actual code directly in thread, why should I have to deal with all these nuances of AsyncTask then? – We are Borg Jul 15 '15 at 12:43
No. Just replace your `doInBackground()` call with `execute()`. The async task framework will take it from there. – laalto Jul 15 '15 at 12:44
Thanks, that worked. But I am unable to get the result in PostExecute. I have updated my code in the main post. Can you have a look. – We are Borg Jul 15 '15 at 12:56

score 0 · Answer 2 · edited May 23 '17 at 12:22

0

You are calling doInBackground form the UI therad! In order to start an AsyncTask you need to call execute. executeRestLogin.execute()

Edit:

Dont forget conventions a class starts with an upper case.

Call execute on the AysnTask object will start the task. This tutorial will make it clearer.

edited May 23 '17 at 12:22

Community

1
1

answered Jul 15 '15 at 12:37

EE66

4,601
1
17
20

It expects a Runnable object, so do I have to create a new Thread? Then what's the point of using Async because I can do already all this stuff within a Thread. – We are Borg Jul 15 '15 at 12:44

score 0 · Answer 3 · answered Jul 15 '15 at 12:51

0

You should replace the doInBackground() by execute(). With that the code in doInBackground method will be executed in another thread.(you should not create a new thread, Android does it for you.)

answered Jul 15 '15 at 12:51

eljec

172
1
9

AmirHossein Manian · Answer 4 · 2016-08-27T05:24:10.287

Change your code like:

private class ExecuteRestLogin extends AsyncTask<Void,Void,Boolean> {
 @Override
    protected Boolean doInBackground(Void... params) {
        HttpHeaders requestHeaders = new HttpHeaders();
        requestHeaders.add("Cookie", "JSESSIONID=" + StaticRestTemplate.jsessionid);
        HttpEntity<String> requestEntity = new HttpEntity<>(requestHeaders);

        HttpEntity<String> rssResponse = rest.exchange(
                "http://192.168.178.60:8080/dashboard",
                HttpMethod.GET,
                requestEntity,
                String.class);
        StaticRestTemplate.jsessionid = rssResponse.getBody();
        result = StaticRestTemplate.jsessionid; // result is a global String.
        return true;
    }

 @Override
    protected void onPostExecute(final Boolean success) {
         if (success) {
            //You can use your result string now.
        }
    }
}

Android : Network on main thread exception even when using AsyncTask

4 Answers4

Linked