android - Invoking new activity class when a tab is clicked in actionbarsherlock -

folks,

i new android development question basic - using tabbed pane actionbarsherlock , want have 3 different ui 3 tabs. need 1 textbox in common across tabs. achieve first thing idea have 3 different activity classes extending actionbar.tablistener instantiating classes (using new) settablistener not working. solution?

regards,

the main activity class -

       actionbar.tab atab = getsupportactionbar().newtab();     atab.settext("a");     atab.settablistener(new aactivity());     getsupportactionbar().addtab(atab);      actionbar.tab btab = getsupportactionbar().newtab();     btab.settext("b");     btab.settablistener(new messageactivity());     getsupportactionbar().addtab(btab);      actionbar.tab ctab = getsupportactionbar().newtab();     ctab .settext("c");     ctab .settablistener(new dataactivity());     getsupportactionbar().addtab(ctab ); 

now aactivity class -

  public class aactivity extends activity implements actionbar.tablistener {  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_call); }  @override public boolean oncreateoptionsmenu(menu menu) {     // inflate menu; adds items action bar if present.     getmenuinflater().inflate(r.menu.call, menu);     return true; }  @override public void ontabselected(tab tab, fragmenttransaction ft) {     system.out.println("in a");     textview txtview = (textview) findviewbyid(r.id.alog);  }  @override public void ontabunselected(tab tab, fragmenttransaction ft) {     // todo auto-generated method stub  }  @override public void ontabreselected(tab tab, fragmenttransaction ft) {     // todo auto-generated method stub  }  } 

it giving me nullpointer @

 textview txtview = (textview) findviewbyid(r.id.alog) 

so assuming new thing not working @ all

you're doing wrong.

the tablistener interface allows respond when tab selected or unselected. how respond you. doesn't matter if implementing class activity or other particular class - long implements methods of tablistener in way or another.

you should never have instantiate activity class through new myactivity(). android needs can set environment activity. thus, if want launch activity when tab selected, should calling startactivity inside ontabselected. however, launching activity when selecting tab bad idea. open separate activity (outside of original tabbed activity) , won't have tabbed action bar.

you're looking fragments: single activity container holding fragment can swap other fragments. when selecting tab, want replace current fragment fragment specific tab. demonstrated in actionbarsherlock samples, fragmenttabs.tabmanager handles binding between tabs , fragments. use in code, should:

1. make mainactivity extend sherlockfragmentactivity.
2. grab layout fragment_tabs.xml.
3. grab tabmanager class fragmenttabs.java , copy codebase (as separate class or static inner class, whatever works).

4. copy setup code fragmenttabs.oncreate:

   super.oncreate(savedinstancestate);  setcontentview(r.layout.fragment_tabs); mtabhost = (tabhost)findviewbyid(android.r.id.tabhost); mtabhost.setup();  mtabmanager = new tabmanager(this, mtabhost, r.id.realtabcontent); 

5. create tabs tabmanager.addtab, example:

   mtabmanager.addtab(mtabhost.newtabspec("taba").setindicator("a"),         afragment.class, null); 

6. make fragment classes each tab (e.g. afragment). override fragment.oncreateview, inflate ui , fancy stuff.

also, read fragments developer guide!