Fragment Backstack issue in Map Application
<p>It tring to get Map View in fragment i'm getting error when navigate to another fragment and back to map view . i had created a object to replace fragment but i get log cat  fragment already added </p>

<pre><code>    package com.Raja.Avantaj;

import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapView;
import com.google.android.maps.MyLocationOverlay;

import android.app.Fragment;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class MapFragment extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        View v = inflater.inflate(R.layout.mapfragment, container, false);
        return v;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onActivityCreated(savedInstanceState);
        MapView map = new MapView(getActivity(), "0LYqpa9x_HkkUzATV8Rt5MHwhUuvm7sbnxsvZWQ");
        map.setClickable(true);
        map.getController().setCenter(new GeoPoint((int)(8.532138 * 1E6),(int)(76.961583 * 1E6)));
        map.getController().setZoom(9);
        map.setBuiltInZoomControls(true);
        Drawable marker=getResources().getDrawable(R.drawable.balloon);
        marker.setBounds(0, 0, marker.getIntrinsicWidth(),
                marker.getIntrinsicHeight());
        map.getOverlays().add(new AvantajOverLay(marker));
        MyLocationOverlay me=new MyLocationOverlay(getActivity(), map);
        map.getOverlays().add(me);
        ((ViewGroup)getView()).addView(map);
    }

}
</code></pre>

<p>i'm calling fragment here</p>

<pre><code>    package com.Raja.Avantaj;

import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;

/**
 * @author user5
 *
 */
public class ContactUs extends Fragment {
    Button mapus;
    View v;
    Fragment frag1;
    /* (non-Javadoc)
     * @see android.app.Fragment#onCreateView(android.view.LayoutInflater, android.view.ViewGroup, android.os.Bundle)
     */

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        // TODO Auto-generated method stub
         v = inflater.inflate(R.layout.contactus, container, false);
        intilize();
        return v;
    }
    // add a button to display the map
    private void intilize() {
        // TODO Auto-generated method stub
        mapus = (Button)v.findViewById(R.id.map);
        mapus.setOnClickListener(btnOnClickListener);

    }

    Button.OnClickListener btnOnClickListener = new Button.OnClickListener(){

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            /*Toast.makeText(getActivity(),"Why didn't come", Toast.LENGTH_LONG).show();
            Intent intent=new Intent(v.getContext(),MapUs.class);
            ContactUs.this.startActivity(intent);*/

            FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();



             if(getFragmentManager().findFragmentByTag("MapFragment")==null)
            {   
                Log.d("in  null","in null" );
                frag1 = new MapFragment(); 
                fragmentTransaction.replace(R.id.layoutfordetails, frag1,"MapFragment");    
                //fragmentTransaction.addToBackStack("MapFragment");
            }


                else
                {
                    Log.d("in not null","in not null" );
                    Fragment f11 = getFragmentManager().findFragmentByTag("MapFragment");
                    fragmentTransaction.replace(R.id.layoutfordetails, f11,"MapFragment");

                    //fragmentTransaction.addToBackStack("MapFragment");
                }
            fragmentTransaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
            fragmentTransaction.commit();


        }

    };

}
</code></pre>

<p>Error i get this Logcat</p>

<pre><code>03-19 13:16:45.214: W/dalvikvm(425): threadid=1: thread exiting with uncaught exception (group=0x40014760)
03-19 13:16:45.294: E/AndroidRuntime(425): FATAL EXCEPTION: main
03-19 13:16:45.294: E/AndroidRuntime(425): java.lang.IllegalStateException: Fragment already added: MapFragment{41000090 #2 id=0x7f080018 MapFragment}
03-19 13:16:45.294: E/AndroidRuntime(425):  at android.app.BackStackRecord.doAddOp(BackStackRecord.java:322)
03-19 13:16:45.294: E/AndroidRuntime(425):  at android.app.BackStackRecord.replace(BackStackRecord.java:360)
03-19 13:16:45.294: E/AndroidRuntime(425):  at com.Raja.Avantaj.ContactUs$1.onClick(ContactUs.java:70)
03-19 13:16:45.294: E/AndroidRuntime(425):  at android.view.View.performClick(View.java:3110)
</code></pre>
