Android - problemas con app inicio de sesion

e tal amigos, tengo una aplicacion movil que debe conectar a moodle, sin embargo al tratar de realizar el login me aparece el siguiente error , soy nuevo en java, alguien puede ayudarme please

11-04 23:47:17.205 5524-5524/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1118)
at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
at java.net.InetAddress.getAllByName(InetAddress.java:214)
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:670)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:769)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:743)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:732)
at moodle.android.APLICACIONMOVILDECAMPUSVIRTUAL.General.TokenHttpRequest.doHTTPRequest(TokenHttpRequest.java:29)
at moodle.android.APLICACIONMOVILDECAMPUSVIRTUAL.General.Login.onClick(Login.java:138)
at android.view.View.performClick(View.java:4198)
at android.view.View$PerformClick.run(View.java:17158)
at android.os.Handler.handleCallback(Handler.java:615)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4918)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1004)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:771)
at dalvik.system.NativeStart.main(Native Method)

///////////////////////////////////////////////////////////////////////////////////////////////

aqui estan mis dos clases
public class Login extends Activity implements OnClickListener {



Button login;
EditText siteUrl, username, password;
User user;
SharedPreferences saved;
String loginDetails;

ProgressDialog dialog;


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

try {
siteUrl = (EditText) findViewById(R.id.moodle_url);
username = (EditText) findViewById(R.id.username);
password = (EditText) findViewById(R.id.password);
login = (Button) findViewById(R.id.login_button);

try {
//
siteUrl.setHint(R.string.login_url_hint);
username.setHint(R.string.login_username_hint);
password.setHint(R.string.login_password_hint);


siteUrl.setText("https://uacjmoodle.milaulas.com");
username.setText("juan_guardado");
password.setText("Prueba123#");


} catch (Exception e) {
Log.e("NoPreferences", e.toString());
}

login.setOnClickListener(this);

} catch (Exception e) {
Log.e("Error With Login", e.toString());
}


}



@Override
public void onClick(View v) {


switch (v.getId()) {
case R.id.login_button:


dialog = ProgressDialog.show(this, "",
"Verificando Ususrio y Contraseña", true);


if (AppStatus.getInstance(Login.this).isOnline(Login.this)) {
String conType = AppStatus.getInstance(Login.this).getConnectionType(Login.this);
conType = conType == null ? "No hay cursos visibles" : conType;
Toast.makeText(getApplicationContext(), "Estas en linea (" + conType + ")!!!!", Toast.LENGTH_LONG).show();


} else {
messageHandler.sendEmptyMessage(0);

Toast.makeText(getApplicationContext(), "No tienes Internet!!!!", Toast.LENGTH_LONG).show();


}
String siteUrlVal = siteUrl.getText().toString();


String usr = username.getText().toString();
String pwd = password.getText().toString();


String usrUri = Uri.encode(usr);
String pwdUri = Uri.encode(pwd);


saved = getSharedPreferences(loginDetails, MODE_PRIVATE);

SharedPreferences.Editor e = saved.edit();
e.putString("siteUrlVal", siteUrlVal);
e.putString("usr", usr);
e.putString("pwd", pwd);
e.commit();
//moodle_mobile_app
String url = siteUrlVal + "/login/token.php?username=" + usrUri + "&password=" + pwdUri + "&rest";
//url = "https://uacjmoodle.milaulas.com/login/token.php?username=festrada&password=Profesor123!&service=&service=moodle_mobile_app";//&service=moodle_mobile_app


TokenHttpRequest tokenRequest = new TokenHttpRequest();
String token = tokenRequest.doHTTPRequest(url);
//se quito la llamada a tokenrequest y se le asigna el token manual
//se declara este tocken para acceder a la informacion del usuario festrada
//String token= "700c1d9f3af35836885b12a65a584e1e"; //acceder a la informacion del usuario festrada

if (token != null && token != "")
{


String serverurl = siteUrlVal + "/webservice/rest/server.php" + "?wstoken=" + token + "&wsfunction=";

user = new User();
user.setUsername(usr);
user.setPassword(pwd);
user.setToken(token);
user.setTokenCreateDate();
user.setUrl(url);

//AQUI SE MANDA LLAMAR A LA CLASE MOODLEWEBSERVICE
//PARA OBTENER LA INFORMACION DE LOS CURSOS EN LO QUE ESTA INSC
//Y LA INFORMACION DE LOS CURSOS
//crea objeto de tipo Moodlewebservice, para poder mandar llamar getSiteinfo
MoodleWebService webService = new MoodleWebService(Login.this);

//crea objeto siteInfo para envianrselo vacio como parametro a funcion getsiteinfo
SiteInfo siteInfo = new SiteInfo();

//IdUser idUser = new IdUser();

//LLAMADA A 1ER WEBSERVICE PARA OBTENER DATOS DE DOC XML NOMBRE COMPLETO DE USUARIO Y NOMBRE D SITIO)
webService.getSiteinfo(serverurl, siteInfo);//llamada a webservice 1

user.setSiteInfo(siteInfo);



ArrayList<Course> courses = new ArrayList<Course>();




if (courses.size() > 0) {
for (int i = 0; i < courses.size(); i++) {

Course c = courses.get(i);
ArrayList<CourseContent> coursecontents = new ArrayList<CourseContent>();

webService.getCourseContents(serverurl, c.getId(), coursecontents);

if (coursecontents.size() > 0) {
c.setCourseContent(coursecontents);
}
} //fin for

user.setCourses(courses);
Intent nextPage;

//
nextPage = new Intent(Login.this, CourseDetail.class);
nextPage.putExtra("userObject", user);


startActivity(nextPage);
} else {
messageHandler.sendEmptyMessage(0);

Log.e("Course Error", "Usuario no esta inscrito en un curso");
Toast.makeText(getApplicationContext(), "No tienes curso(s) asignados", Toast.LENGTH_LONG).show();

}


} else {
messageHandler.sendEmptyMessage(0);

Toast.makeText(getApplicationContext(), "El usuario o contraseña son incorrectos. Intenta de nuevo!", Toast.LENGTH_LONG).show();
Toast.makeText(getApplicationContext(), "Verifica si el sitio tiene habilitado el protocolo REST", Toast.LENGTH_LONG).show();
}


break;
default:


}
}



private Handler messageHandler = new Handler() {

public void handleMessage(Message msg) {
super.handleMessage(msg);
dialog.dismiss();

}
};
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

public class TokenHttpRequest {


public String doHTTPRequest(String url){
String responseBody = "";
String token = "";

DefaultHttpClient httpClient = new DefaultHttpClient();


HttpGet httpPost = new HttpGet(url);

try {
ResponseHandler<String> responseHandler=new BasicResponseHandler();
responseBody = httpClient.execute(httpPost, responseHandler);

JSONObject jObject = new JSONObject(responseBody);
token = jObject.getString("token");
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClientProtocolException e) {
// writing exception to log
e.printStackTrace();
} catch (IOException e) {
// writing exception to log
e.printStackTrace();
}
return token;
}

}