Method getText() must be called from the UI Thread (Android Studio)

Question

I\'m trying to create a login for an application. However I have a problem.

This is my code:

package com.forgetmenot.loginregister;


import java.uti         


        

Answer 1

Try to pass Your values to Login AsyncTask via execute(param1, param1, ..., paramN) method:

submit.setOnClickListener(new View.OnClickListener() {

           @Override
           public void onClick(View arg0) {

               String username = uname.getText().toString();
               String pass = password.getText().toString();
               new Login().execute(username, pass);

           }
       });
    }
    private void findViewsById() {

        uname = (EditText) findViewById(R.id.txtUser);
        password = (EditText) findViewById(R.id.txtPass);
        submit = (Button) findViewById(R.id.login);
    }
    private class Login extends AsyncTask<String, String, String>{

        @Override
        protected String doInBackground(String... args) {
            // Getting username and password from user input

            String username = args[0];
            String pass = args[1];

Answer 2

The exception is thrown because doInBackground() is invoked from a background thread. I would add two String parameters to the constructor of your Login class.

I would like to advise you to gain more knowledge about AsyncTasks and Threading on Android. For example, there is a page in the official docs: http://developer.android.com/guide/components/processes-and-threads.html.

You might also take a look at this course: https://www.udacity.com/course/developing-android-apps--ud853. You can learn a lot of basics of the Android framework.

Answer 3

make username and pass login class variable and override onPreExcecute() and do this:

    @Override
    protected void onPreExecute() {

        username = uname.getText().toString();
        pass = password.getText().toString();

    }

Answer 4

Unless something has changed that I'm not aware of, that shouldn't be a problem. UI elements can't be updated from the background but accessing their getters has never been an issue.

Anyway, you can get around this by adding a constructor to your AsyncTask which would take the two Strings then send them when creating your task.

private class Login extends AsyncTask<String, String, String>{

    // member variables of the task class
    String uName, pwd
    public Login(String userName, String password) {
        uName = userName;
        pwd = password;
    }

    @Override
    protected String doInBackground(String... args) {...}

and pass them in your onClick()

 @Override
 public void onClick(View arg0) {
     // execute method invokes doInBackground() where we open a Http URL connection using the given Servlet URL
     //and get output response from InputStream and return it.

     // pass them here
     new Login(uname.getText().toString(), password.getText().toString()).execute();
 }

Answer 5

You're accessing the UI thread from a background thread here:

String username = uname.getText().toString();
String pass = password.getText().toString();

What you want to do is just pass the username/password strings in to your background task constructor or you could pass them directly to the execute method. I prefer to define them in to the constructor if they are going to be required (like yours are).

Define your LoginTask like

String uname;
String password;
public Login(String username, String password({
    this.uname = username;
    this.password = password;
}

Then in doInBackground() you use the members instead.

List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("u",this.username));
params.add(new BasicNameValuePair("p",this.pass));
json = jParser.makeHttpRequest(url_login, "GET", params);

Edit - so then your new Login().execute() call would look more like this

new Login(uname.getText().toString(), password.getText().toString()).execute();