I m trying to display a map in a set of tabs, using fragments. The problem I m having is the map activity disappears if the user navigates to another fragment, then back. How can I display a MapActivity in fragments in a tabhost?

其依据是围绕如何将地图方法与碎块混为一谈的许多问题(见)。 MapView in a Fragment (Honeycomb)

MainTabActivity has a tabhost and uses FragmentManager to display Fragments in the tabs. MapFragment has a tabhost and uses it to display a MapActivity.
MapFragment does use LocalActivityManager to propogate lifecycle events to the the contained activity.

So MapFragment:

   public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.map_fragment, container, false);
        mTabHost = (TabHost) view.findViewById(android.R.id.tabhost);
        mTabHost.setup(getLocalActivityManager());
        Intent intent = new Intent(getActivity(), MapActivityWrapper.class);
//        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);//does nothing
        TabHost.TabSpec tab = mTabHost.newTabSpec("map")
                .setIndicator("map")
                .setContent(intent);
        mTabHost.addTab(tab);
        return view;
    }

地图集:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="fill_parent"
              android:layout_height="fill_parent"
              android:orientation="vertical">
    <TabHost xmlns:android="http://schemas.android.com/apk/res/android"
             android:id="@android:id/tabhost"
             android:layout_width="fill_parent"
             android:layout_height="fill_parent">
        <LinearLayout android:orientation="vertical"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent">
            <TabWidget android:id="@android:id/tabs"
                    android:visibility="gone"
                    android:layout_width="fill_parent"
                    android:layout_height="wrap_content"/>
            <FrameLayout android:id="@android:id/tabcontent"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"/>
        </LinearLayout>
    </TabHost>
</LinearLayout>

The Code in MainTabActative for changing the tab content:

private void updateTab(String oldId, String tabId) {
    FragmentManager fm = getSupportFragmentManager();
    Fragment old = fm.findFragmentByTag(oldId);
    Fragment selected = fm.findFragmentByTag(tabId);
    FragmentTransaction ft = fm.beginTransaction();
    boolean added = false;
    if (selected == null) {
        selected = createFragment(tabId);
    } else {
        try {
            ft.remove(selected);
        } catch (Exception e) {
            ft.add(android.R.id.tabcontent, selected, tabId);
            added = true;
            //exception for removing an unadded fragment... why throw an exception?
        }
    }
    if (old != null) ft.remove(old);
    if (!added) ft.replace(android.R.id.tabcontent, selected, tabId);
    if (!creating && !backStackProcessing) ft.addToBackStack(null);//member vars
    ft.commit();
}

主要的TabActivity下岗(删除了一个与外界无关的布局):

<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@android:id/tabhost"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:background="#EFEFEF">
    <RelativeLayout android:layout_width="fill_parent"
            android:layout_height="fill_parent">
        <FrameLayout android:id="@android:id/tabcontent"
                android:layout_gravity="top"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:background="@color/app_default_bg"
                android:layout_above="@+id/ad_region"
                android:layout_below="@+id/quick_action_region">
            <FrameLayout android:id="@+id/tab1"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"/>
            <FrameLayout android:id="@+id/tab2"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"/>
            <FrameLayout android:id="@+id/map_tab"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"/>
            <FrameLayout android:id="@+id/tab3"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"/>
        </FrameLayout>
        <TabWidget android:layout_width="fill_parent"
                   android:id="@android:id/tabs"
                   android:layout_height="wrap_content"
                   android:layout_alignParentBottom="true"
                   android:layout_alignParentLeft="true"/>
    </RelativeLayout>
</TabHost>

Again - The problem I m having is the map activity disappears if the user navigates to another fragment, then back. How can I display a MapActivity in fragments in a tabhost?

非常感谢。