error android.os.networkonmainthreadexception asynctask getResponseCode
<p>when run my code on the same class is app run good. but when i run this code on two class different, my app was error android.os.networkonmainthreadexception.
when debug i detect error at <strong>responseHttp = httpConnection.getResponseCode();</strong>
app run to line <strong>responseHttp = httpConnection.getResponseCode();</strong> and it go to catch{},it cancel "If..else".And log error android.os.networkonmainthreadexception.
Can you help me!!</p>

<p>My code class Asynctask</p>

<pre><code>package com.example.finishdemo;

import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import android.os.AsyncTask;

public class TestConnectionNew extends AsyncTask&lt;String, Void, String&gt; {
private int responseHttp = 0;
private String flag="false";

@Override
protected String doInBackground(String... urltest) {
    // TODO Auto-generated method stub
    try {
        URL url = new URL(urltest[0]);
        URLConnection connection = url.openConnection();
        connection.setConnectTimeout(2000);
        HttpURLConnection httpConnection = (HttpURLConnection) connection;
        **responseHttp = httpConnection.getResponseCode();**
        if (responseHttp == HttpURLConnection.HTTP_OK) {
            flag = "true";
        } else {
            flag = "false";
        }
    } catch (Exception e) {
        e.printStackTrace();
        System.out.println("Thong bao loi: "+e.toString());
    }
    return flag;
}
}
</code></pre>

<p>Code class main:</p>

<pre><code>package com.example.finishdemo;
public class Hoadon extends Activity {
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.hoadon);
    TestConnectionNew t=new TestConnectionNew();
    String recieve=t.doInBackground("http://longvansolution.tk/monthlytarget.php");
    if(recieve.equalsIgnoreCase("true"))
    {
        doTimerTask();
    }else
        if(recieve.equalsIgnoreCase("false"))
    {
        showAlert("Không kết nối được đến server hoặc thiết bị chưa có kết nối internet!");
    }
</code></pre>
