Error "Only The Original Thread That Created A View Hierarchy Can Touch Its Views" In Android

I am creating a simple app for login using Android and PHP but I get an error, can anyone help me? I am trying to make a relation between the Android as the client side and PHP/MyS

Solution 1:

The solution is in the log from logcat:

04-04 18:38:47.596: E/AndroidRuntime(413): android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.

Posting user/password is working. You get the "true" response alright, but then you try to set a label or similar, in a view that was created outside the thread. That's a no-no.

result.setText("Login successful");

Look at the Android SDK docs about threads/processes on how to update views from other threads: http://developer.android.com/guide/components/processes-and-threads.html

Solution 2:

OK I made some modifications to your code it's still ugly and requires lots of refactoring but tell me if it throws any exceptions.

EDIT: Added your username and password passing to the request as parameters to your postLoginData(String password,String username) method. That should do it.

---

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;

import android.os.Bundle;
import android.os.StrictMode;
import android.app.Activity;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class AndroidLogin extends Activity implements OnClickListener {


    Button ok, back, exit;
    TextView result;
    EditText uname;
    EditText pword;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);


        StrictMode.ThreadPolicy policy = 
        new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);

        // Login button clicked
        ok = (Button) findViewById(R.id.btn_login);
        ok.setOnClickListener(this);
        uname = (EditText) findViewById(R.id.txt_username);
        pword = (EditText) findViewById(R.id.txt_password);
        result = (TextView) findViewById(R.id.lbl_result);


    }

    @Override
    public void onClick(View view) {
        // TODO Auto-generated method stub
        final String resultText;   

        final String username = uname.getText().toString();           
        final String password = pword.getText().toString();


        if (view == ok) {
            Thread t = new Thread() {

                public void run() {
                    postLoginData(username,password);
                }
            };
            t.start();

        }
    }

    private void postLoginData(String username,String password) {

        try {
            // Create a new HttpClient and Post Header
            HttpClient httpclient = new DefaultHttpClient();
            Log.e("Response-->", "after httpclient");
        /* login.php returns true if username and password is equal to saranga */
            HttpPost httppost = new HttpPost("http://10.0.2.2/login.php");
            Log.e("Response-->", "after httppost");


            List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
            nameValuePairs.add(new BasicNameValuePair("username", username));
            nameValuePairs.add(new BasicNameValuePair("password", password));

            httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
            Log.e("Responce-->", "after using the list name pair");

            // Execute HTTP Post Request
            Log.w("SENCIDE", "Execute HTTP Post Request");
            HttpResponse response = httpclient.execute(httppost);
            Log.e("Responce-->", "after execute the http response");
            String str = EntityUtils.toString(response.getEntity(), HTTP.UTF_8);

            if (str.toString().equalsIgnoreCase("true")) {

                runOnUiThread(new Runnable() {
                    public void run() {
                        result.setText("Login Successful");

                    }
                });


            } else {
                runOnUiThread(new Runnable() {
                    public void run() {
                        result.setText("Duh");

                    }
                });
            }

        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }


}

Solution 3:

You may not make changes to android views off the main UI thread. In your example you are starting a new thread and running postLoginData() on it. Because postLoginData ALSO sets the text of a textview you get this error.

You should: do the http request on your new thread, then on the UI thread change the text.

There are a variety of ways to do this.

• AsyncTask
• Handler

And this super simple but probably not advised way to do it to just get you on your feet. Yo will want to do this anytime you are making a change inside your new thread to the UI, so in this example when you are setting the text of result.

result.post(new Runnable() {
        public void run() {
            result.setText(str);
        }
    });
}

Which will run on the UI thread. You really should look at the two options I posted first or you will just run into more trouble.

** edit ** You need to just replace this code to publish on the main thread instead of the new thread.

if(str.toString().equalsIgnoreCase("true"))
{
 Log.w("SENCIDE", "TRUE");
 result.setText("Login successful");  
}else
{
 Log.w("SENCIDE", "FALSE");
 result.setText(str);            
}

Make it look like this:

final String resultText;
if(str.toString().equalsIgnoreCase("true")) {
    resultText = "Login successful";
}else {
    resultText = str;
}
result.post(new Runnable() {
        public void run() {
            result.setText(resultText);
        }
    });
}