My question is about thread management, configuration changes, and fragments. I know that Android guarantees that when a configuration change takes place, no messages are dispatched in the UI thread until the activity gets recreated (its onCreate() method finishes). This behaviour is documented in the onRetainNonConfigurationInstance() method, and has been discussed in Stackoverflow and Google Groups.

However, in regards to fragments, I haven't been able to find such guarantees in the documentation. In The Busy Coder's Guide to Android Development, however, you say (page 380 from PDF of the last version of the guide) that such guarantee holds. In particular, you say:

"Android guarantees that, while on the main application thread, getActivity() will
return a valid Activity. Moreover, once the configuration change starts, no
messages on the message queue will be processed until after onCreate() of the
hosting activity (and onActivityCreated() of the fragment) have completed their
work."

But I haven't been able to find the "onActivityCreated()" guarantee anywhere in the docs. So my question is, where is that relevant piece of information officially documented?

TabHost tabs=(TabHost)findViewById(R.id.tabhost);
        tabs.setup();
        // login tag
        TabHost.TabSpec login=tabs.newTabSpec("tag1");
        login.setContent(new Intent(this, Login.class));
        login.setIndicator("Login/Logout",getResources().getDrawable(android.R.drawable.ic_dialog_info));
        tabs.addTab(login);

When executing the addTab line I get the following exception:

01-08 09:31:01.903: E/AndroidRuntime(1426): Caused by: java.lang.IllegalStateException: Did you forget to call 'public void setup(LocalActivityManager activityGroup)'?
01-08 09:31:01.903: E/AndroidRuntime(1426): 	at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:655)
...

In Android 1.x and 2.x, if you wanted tabs, you usually trotted out TabHost
and TabWidget.
On Android 3.x, that is being replaced by tabs managed in the action bar.