为什么在TabActivity中发生未捕获的异常？

Question

I have created a TabActivity and added TabWidget and frame to the layout.

I have four other Activity classes with single label in each Activity. Four tabs are associated with four tabs.

When I am trying to launch the application in emulator, I am getting the below exception

09-03 23:24:43.905: ERROR/AndroidRuntime(450): java.lang.NullPointerException 09-03 23:24:43.905: ERROR/AndroidRuntime(450): at android.widget.TabHost.dispatchWindowFocusChanged(TabHost.java:295) 09-03 23:24:43.905: ERROR/AndroidRuntime(450): at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:661) 09-03 23:24:43.905: ERROR/AndroidRuntime(450): at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:661)

public class TabHome extends TabActivity {

public void onCreate(Bundle savedInstanceState)
{

    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    TabHost tabHost=getTabHost();
    TabHost.TabSpec tabSpec;
    Resources res=getResources();

    Intent intent;

    intent=new Intent().setClass(this, MyMap.class);        
    tabSpec=   tabHost.newTabSpec("Maps").setIndicator("Maps",res.getDrawable(R.drawable.ic_tab_artists)).setContent(intent);       
    tabHost.addTab(tabSpec);

    intent=new Intent().setClass(this, MyStash.class);      
    tabSpec=  tabHost.newTabSpec("Stash").setIndicator("Stash",res.getDrawable(R.drawable.ic_tab_artists)).setContent(intent);      
    tabHost.addTab(tabSpec);

    intent=new Intent().setClass(this, MyList.class);       
    tabSpec=  tabHost.newTabSpec("List").setIndicator("List",res.getDrawable(R.drawable.ic_tab_artists)).setContent(intent);        
    tabHost.addTab(tabSpec);

    intent=new Intent().setClass(this, MySearch.class);     
    tabSpec=  tabHost.newTabSpec("Search").setIndicator("Search",res.getDrawable(R.drawable.ic_tab_artists)).setContent(intent);        
    tabHost.addTab(tabSpec);

    tabHost.setCurrentTab(2);


}

Answer 1

I have missed to mention the following attributes to main.xml

android:id="@android:id/tabhost" in TabHost tag

and

android:id="@android:id/tabs" in TabWidget tag

and

android:id="@android:id/tabcontent" in FrameLayout tag.

Thanks all for your help!