Duplicate ID, tag null, or parent id with another fragment for com.google.android.gms.maps.MapFragment

I have an application with three tabs.

Each tab has its own layout .xml file. The main.xml has its own map fragment. It's the one that shows up when the application first launches.

Everything works fine except for when I change between tabs. If I try to switch back to the map fragment tab, I get this error. Switching to and between other tabs works just fine.

What could be wrong here?

This is my main class and my main.xml, as well as a relevant class that I use ( you will also find the error log at the bottom )

main class

package com.nfc.demo;

import android.app.ActionBar;
import android.app.ActionBar.Tab;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.widget.Toast;

public class NFCDemoActivity extends Activity {

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        ActionBar bar = getActionBar();
        bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
        bar.setDisplayOptions(0, ActionBar.DISPLAY_SHOW_TITLE);

        bar.addTab(bar
                .newTab()
                .setText("Map")
                .setTabListener(
                        new TabListener<MapFragment>(this, "map",
                                MapFragment.class)));
        bar.addTab(bar
                .newTab()
                .setText("Settings")
                .setTabListener(
                        new TabListener<SettingsFragment>(this, "settings",
                                SettingsFragment.class)));
        bar.addTab(bar
                .newTab()
                .setText("About")
                .setTabListener(
                        new TabListener<AboutFragment>(this, "about",
                                AboutFragment.class)));

        if (savedInstanceState != null) {
            bar.setSelectedNavigationItem(savedInstanceState.getInt("tab", 0));
        }
        // setContentView(R.layout.main);

    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt("tab", getActionBar().getSelectedNavigationIndex());
    }

    public static class TabListener<T extends Fragment> implements
            ActionBar.TabListener {
        private final Activity mActivity;
        private final String mTag;
        private final Class<T> mClass;
        private final Bundle mArgs;
        private Fragment mFragment;

        public TabListener(Activity activity, String tag, Class<T> clz) {
            this(activity, tag, clz, null);
        }

        public TabListener(Activity activity, String tag, Class<T> clz,
                Bundle args) {
            mActivity = activity;
            mTag = tag;
            mClass = clz;
            mArgs = args;

            // Check to see if we already have a fragment for this tab,
            // probably from a previously saved state. If so, deactivate
            // it, because our initial state is that a tab isn't shown.
            mFragment = mActivity.getFragmentManager().findFragmentByTag(mTag);
            if (mFragment != null && !mFragment.isDetached()) {
                FragmentTransaction ft = mActivity.getFragmentManager()
                        .beginTransaction();
                ft.detach(mFragment);
                ft.commit();
            }
        }

        public void onTabSelected(Tab tab, FragmentTransaction ft) {
            if (mFragment == null) {
                mFragment = Fragment.instantiate(mActivity, mClass.getName(),
                        mArgs);
                ft.add(android.R.id.content, mFragment, mTag);
            } else {
                ft.attach(mFragment);
            }
        }

        public void onTabUnselected(Tab tab, FragmentTransaction ft) {
            if (mFragment != null) {
                ft.detach(mFragment);
            }
        }

        public void onTabReselected(Tab tab, FragmentTransaction ft) {
            Toast.makeText(mActivity, "Reselected!", Toast.LENGTH_SHORT)
                         .show();
        }
    }

}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <fragment
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/mapFragment"
        android:name="com.google.android.gms.maps.MapFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>

relevant class ( MapFragment.java )

package com.nfc.demo;

import android.app.Fragment;
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) {
        super.onCreateView(inflater, container, savedInstanceState);
        return inflater.inflate(R.layout.main, container, false);
    }

    public void onDestroy() {
        super.onDestroy();
    }
}

error

android.view.InflateException: Binary XML file line #7: 
     Error inflating class fragment
   at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:704)
   at android.view.LayoutInflater.rInflate(LayoutInflater.java:746)
   at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
   at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
   at com.nfc.demo.MapFragment.onCreateView(MapFragment.java:15)
   at android.app.Fragment.performCreateView(Fragment.java:1695)
   at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:885)
   at android.app.FragmentManagerImpl.attachFragment(FragmentManager.java:1255)
   at android.app.BackStackRecord.run(BackStackRecord.java:672)
   at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1435)
   at android.app.FragmentManagerImpl$1.run(FragmentManager.java:441)
   at android.os.Handler.handleCallback(Handler.java:725)
   at android.os.Handler.dispatchMessage(Handler.java:92)
   at android.os.Looper.loop(Looper.java:137)
   at android.app.ActivityThread.main(ActivityThread.java:5039)
   at java.lang.reflect.Method.invokeNative(Native Method)
   at java.lang.reflect.Method.invoke(Method.java:511)
   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
   at dalvik.system.NativeStart.main(Native Method)

Caused by: java.lang.IllegalArgumentException: 
     Binary XML file line #7: Duplicate id 0x7f040005, tag null, or 
     parent id 0xffffffff with another fragment for 
     com.google.android.gms.maps.MapFragment
   at android.app.Activity.onCreateView(Activity.java:4722)
   at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:680)
   ... 19 more

The answer Matt suggests works, but it cause the map to be recreated and redrawn, which isn't always desirable. After lots of trial and error, I found a solution that works for me:

private static View view;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    if (view != null) {
        ViewGroup parent = (ViewGroup) view.getParent();
        if (parent != null)
            parent.removeView(view);
    }
    try {
        view = inflater.inflate(R.layout.map, container, false);
    } catch (InflateException e) {
        /* map is already there, just return view as it is */
    }
    return view;
}

For good measure, here's "map.xml" (R.layout.map) with R.id.mapFragment (android:id="@+id/mapFragment"):

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/mapLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <fragment xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/mapFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        class="com.google.android.gms.maps.SupportMapFragment" />
</LinearLayout>

I hope this helps, but I can't guarantee that it doesn't have any adverse effects.

Edit: There were some adverse effects, such as when exiting the application and starting it again. Since the application isn't necessarily completely shut down (but just put to sleep in the background), the previous code i submitted would fail upon restarting the application. I've updated the code to something that works for me, both going in & out of the map and exiting and restarting the application, I'm not too happy with the try-catch bit, but it seem to work well enough. When looking at the stack trace it occurred to me that I could just check if the map fragment is in the FragmentManager, no need for the try-catch block, code updated.

More edits: Turns out you need that try-catch after all. Just checking for the map fragment turned out not to work so well after all. Blergh.

The problem is that what you are trying to do shouldn't be done. You shouldn't be inflating fragments inside other fragments. From Android's documentation:

Note: You cannot inflate a layout into a fragment when that layout includes a <fragment>. Nested fragments are only supported when added to a fragment dynamically.

While you may be able to accomplish the task with the hacks presented here, I highly suggest you don't do it. Its impossible to be sure that these hacks will handle what each new Android OS does when you try to inflate a layout for a fragment containing another fragment.

The only Android-supported way to add a fragment to another fragment is via a transaction from the child fragment manager.

Simply change your XML layout into an empty container (add an ID if needed):

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/mapFragmentContainer"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
</LinearLayout>

Then in the Fragment onViewCreated(View view, @Nullable Bundle savedInstanceState) method:

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    FragmentManager fm = getChildFragmentManager();
    SupportMapFragment mapFragment = (SupportMapFragment) fm.findFragmentByTag("mapFragment");
    if (mapFragment == null) {
        mapFragment = new SupportMapFragment();
        FragmentTransaction ft = fm.beginTransaction();
        ft.add(R.id.mapFragmentContainer, mapFragment, "mapFragment");
        ft.commit();
        fm.executePendingTransactions();
    }
    mapFragment.getMapAsync(callback);
}

I had the same issue and was able to resolve it by manually removing the MapFragment in the onDestroy() method of the Fragment class. Here is code that works and references the MapFragment by ID in the XML:

@Override
public void onDestroyView() {
    super.onDestroyView();
    MapFragment f = (MapFragment) getFragmentManager()
                                         .findFragmentById(R.id.map);
    if (f != null) 
        getFragmentManager().beginTransaction().remove(f).commit();
}

If you don't remove the MapFragment manually, it will hang around so that it doesn't cost a lot of resources to recreate/show the map view again. It seems that keeping the underlying MapView is great for switching back and forth between tabs, but when used in fragments this behavior causes a duplicate MapView to be created upon each new MapFragment with the same ID. The solution is to manually remove the MapFragment and thus recreate the underlying map each time the fragment is inflated.

I also noted this in another answer [1].

This is my answer:

1, Create a layout xml like following:

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/map_container"
android:layout_width="match_parent"
android:layout_height="match_parent">
</FrameLayout>

2, in the Fragment class, add a google map programmatically.

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

/**
 * A simple {@link android.support.v4.app.Fragment} subclass. Activities that
 * contain this fragment must implement the
 * {@link MapFragment.OnFragmentInteractionListener} interface to handle
 * interaction events. Use the {@link MapFragment#newInstance} factory method to
 * create an instance of this fragment.
 * 
 */
public class MapFragment extends Fragment {
    // TODO: Rename parameter arguments, choose names that match
    private GoogleMap mMap;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment_map, container, false);
        SupportMapFragment mMapFragment = SupportMapFragment.newInstance();
        mMap = mMapFragment.getMap();
        FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
        transaction.add(R.id.map_container, mMapFragment).commit();
        return view;
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        Log.d("Attach", "on attach");
    }

    @Override
    public void onDetach() {
        super.onDetach();
    }
}