tabhost的继承与不继承tabactivity

第一种：继承TabActivity 
public class Main extends TabActivity {TabHost tabhost; @Overridepublic void onCreate(Bundle savedInstanceState) 
{super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);tabhost = (TabHost) findViewById(android.R.id.tabhost);
or：
tabhost = getTabHost();
tabhost.setup();
         }
}
第二种：继承ActivityGroup 
public class Main extends ActivityGroup {TabHost tabhost; @Override public void onCreate(Bundle savedInstanceState) 
{  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_main);  tabhost = (TabHost) findViewById(android.R.id.tabhost);  tabhost.setup(getLocalActivityManager());
       }
}
第三种：继承Activity 
public class Main extends Activity {
TabHost tabhost;
 @Override public void onCreate(Bundle savedInstanceState) 
{  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_main);  LocalActivityManager activityGroup = new LocalActivityManager(this,true);tabhost = (TabHost) findViewById(android.R.id.tabhost);
 activityGroup.dispatchCreate(savedInstanceState);  tabhost.setup(activityGroup);  TabHost.TabSpec spec = tabhost.newTabSpec("tag1");  spec.setContent(new Intent(this, Test.class));  spec.setIndicator("第一个选项卡",getResources().getDrawable(R.drawable.ic_launcher));  tabhost.addTab(spec); }
}