How to start activity twice with different layout and not keep it in activity back stack in Android -

i have activities flow:

+--+   +--+   +----+ |a1|-->|a2|-->|home| +--+   +--+   +----+ 

back button in a1 , home should close app. call finish() on a1 when a2 started , on a2 when home started (thanks a1 , a2 never kept on stack).

however, button in a2 should lead a1 override in a2 (a1 finished stated above have start again)

@override public void onbackpressed() {     final intent intent = new intent(getapplicationcontext(), a1.class);     startactivity(intent);     finish(); } 

now, it's possible start again button in home sequence

home (button pressed)->a1->a2->(return home) 

in case (i.e. when a1->a2 started after home) layout of a1 should little bit different.

you need use action, instead of action. read first understand difference http://developer.android.com/training/implementing-navigation/ancestral.html

also, how skip a2, home:

manifest

<activity     android:name="com.yourpackage.a1">     <intent-filter>         <action android:name="android.intent.action.main"/>         <category android:name="android.intent.category.launcher"/>     </intent-filter> </activity>  <activity     android:name="com.yourpackage.a2"       android:parentactivityname="com.yourpackage.a1" >      <!-- parent activity meta-data support 4.0 , lower -->     <meta-data             android:name="android.support.parent_activity"             android:value="com.yourpackage.a1"/> </activity>  <activity     android:name="com.yourpackage.home"       android:parentactivityname="com.yourpackage.a1" >      <!-- parent activity meta-data support 4.0 , lower -->     <meta-data             android:name="android.support.parent_activity"             android:value="com.yourpackage.a1"/> </activity> 

in a2 , in home:

@override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);      // activate navigation in actionbar     getsupportactionbar().setdisplayshowhomeenabled(true);     getsupportactionbar().setdisplayhomeasupenabled(true);      //other stuff  }       @override     public boolean onoptionsitemselected(menuitem item) {         switch (item.getitemid()) {             // respond action bar's up/home button             case android.r.id.home:                 homeupaction();                 return true;         }         return super.onoptionsitemselected(item);     }      private void homeupaction() {         intent upintent = navutils.getparentactivityintent(this);         if (navutils.shoulduprecreatetask(this, upintent)) {             // activity not part of app's task, create new             // task when navigating up, synthesized stack.             taskstackbuilder.create(this)                     // add of activity's parents stack                     .addnextintentwithparentstack(upintent)                             // navigate closest parent                     .startactivities();         } else {             // activity part of app's task, navigate             // logical parent activity.             navutils.navigateupto(this, upintent);         }     }