Android: TabHost without TabActivity

Question

I want to create tabs without extending TabActivity. (The reason is that TabActivity cannot handle a custom titlebar as it seems). I have

public class startTab extends Activity {

 @Override
 public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.mylayout);
        Resources res = getResources();
        LocalActivityManager mlam = new LocalActivityManager(this, false);
        TabHost tabHost = (TabHost) findViewById(R.id.tabhost);
        tabHost.setup(mlam);
        TabHost.TabSpec spec;
        Intent intent;

    intent = new Intent().setClass(this, Show1.class);
    spec = tabHost.newTabSpec("Items").setIndicator("Items", res.getDrawable(R.drawable.items32_ldpi)).setContent(intent);
    tabHost.addTab(spec);

    intent = new Intent().setClass(this, Show2.class);
    spec = tabHost.newTabSpec("Users").setIndicator("Users",res.getDrawable(R.drawable.user32_ldpi)).setContent(intent);
    tabHost.addTab(spec);
}

}

The error I get is

    07-02 07:11:12.715: ERROR/AndroidRuntime(411): 
Caused by: java.lang.IllegalStateException: Activities can't be added until the containing group has been created.

The xml for the view is

<?xml version="1.0" encoding="utf-8"?>
<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
 android:id="@+id/tabhost" android:orientation="vertical" android:layout_width="fill_parent"
 android:layout_height="fill_parent" >
 <LinearLayout android:orientation="vertical"
  android:layout_width="fill_parent" android:layout_height="fill_parent"
  android:paddingTop="5dip">
  <TabWidget android:id="@android:id/tabs"
   android:layout_width="fill_parent" android:layout_height="fill_parent"></TabWidget>
  <FrameLayout android:id="@android:id/tabcontent"
   android:layout_width="fill_parent" android:layout_height="fill_parent"
   android:paddingTop="5dip">
  </FrameLayout>
 </LinearLayout>
</TabHost>

I read somewhere that I have to use a LocalActivityManager, I assume that I am missing something there. Anyone an idea?

Thanks!

Answer 1

Before calling tabHost.setup(mLocalActivityManager); you need to add this line.

mlam.dispatchCreate(savedInstanceState);
tabHost.setup(mlam );

similarly, you need to add for onResume,

mlam.dispatchResume(); 

onPause(),

 mlam.dispatchPause(isFinishing());

Answer 2

Please consider using Views as the contents of your tabs. Not only will this result in less code, less consumed heap space, less consumed stack space, and lower CPU utilization, it will also get you past this problem. Here are two examples showing this technique.

Answer 3

public class ScoreboardActivity extends Activity {
    LocalActivityManager mlam;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_scoreboard);
        mlam = new LocalActivityManager(this, false);
        mlam.dispatchCreate(savedInstanceState);
        TabHost th = (TabHost) findViewById(android.R.id.tabhost);
        th.setup(mlam);
        th.addTab(th.newTabSpec("Numpad").setIndicator("Numpad").setContent(R.id.tab1));
        th.addTab(th.newTabSpec("CardCount").setIndicator("CardCount").setContent(R.id.tab2));
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_scoreboard, menu);
        return true;


    }
    @Override
    protected void onResume(){
        super.onResume();
        mlam.dispatchResume();
    }

    @Override
    protected void onPause(){
        super.onPause();
        mlam.dispatchPause(isFinishing());
    }

}

Answer 4

Design considerations notwithstanding, the following does not work at all, and the API seems to indicate that setContent(Intent i) is valid. This works when the activity extends TabActivity, however, extending Activity and adding setup() call results in an exception at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:649)

Funny thing is, the LogCat suggests I forgot to call setup()

mTabHost = (TabHost) findViewById(android.R.id.tabhost);
mTabHost.setup();

Intent tab1Intent = new Intent(this, ActivityOne.class);
Button tab1View = new Button(this);
tab1View.setText("Activity 1");
  mTabHost.addTab(mTabHost.newTabSpec("tab_1").setIndicator(tab1View).setContent(tab1Intent));