android app crashing on start-up

Question

I am new to android . I am troubling during 2 weeks with an simple android apps which I am developing. In my app , I am trying to fetch a simple text from php . But every time when I try to launch the app it crashed. My code is below

package com.example.test;

import java.io.IOException;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.TextView;

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    HttpClient httpclient = new DefaultHttpClient();
    HttpPost httppost = new HttpPost("http://logger.net46.net/android/hello.php");
    try {
       HttpResponse response = httpclient.execute(httppost);
       final String str =  EntityUtils.toString(response.getEntity());
       TextView tv = (TextView) findViewById(R.id.textView1);
       tv.setText(str);
    } 
   catch (IOException e) {
       // TODO Auto-generated catch block
       e.printStackTrace();
    }



}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

}

I can not finding out where is my problem. Please someone help me.

Answer 1

You are probably getting NetWorkOnMainThreadException. You should use a Thread or AsyncTask for making the http post request and update ui on the ui thread.

Example:

public class MainActivity extends Activity {

    TextView tv; 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv = (TextView) findViewById(R.id.textView1);
        new TheTask().execute();
    }
      class TheTask extends AsyncTask<Void,Void,String>
      {

        @Override
        protected String doInBackground(Void... params) {
            String str = null;
            try
            {
              HttpClient httpclient = new DefaultHttpClient();
              HttpPost httppost = new HttpPost("http://logger.net46.net/android/hello.php");
              HttpResponse response = httpclient.execute(httppost);
              str =  EntityUtils.toString(response.getEntity());     
            } 
            catch (IOException e) {
                   // TODO Auto-generated catch block
                   e.printStackTrace();
                }

            return str;

      }

        @Override
        protected void onPostExecute(String result) {
            // TODO Auto-generated method stub
            super.onPostExecute(result);
            tv.setText(result);
        }

      }
}

Snap