android - Two dynamic fragment on screen (back) -

i have application fragment. start 2 dynamic fragments on screen. on fragment b, have list. when click on item, change 2 fragments c , d.

_____    _____                      _____               _____ | |    | c |                      | |               | | _____ => _____  when back, have : _____   _____ | b |    | d |                      | d |               | b | _____    _____                      _____               _____ 

when press button back, have top fragment change, fragment d stay visible whereas want see a/b.

this class :

public class mainactivity extends activity implements         fragmentblistener,         fragmentclistener {      private static final string tag_fragment_a = "fragmentatag";     private static final string tag_fragment_b = "fragmentbtag";     private static final string tag_fragment_c = "fragmentctag";     private static final string tag_fragment_d = "fragmentdtag";      fragmentmanager fragmentmanager = getfragmentmanager();      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);     }      @override     protected void onrestart() {         super.onrestart();     }      @override     protected void onstart() {         super.onstart();         initfragments();     }      private void initfragments() {         setfragment(tag_fragment_a, r.id.top_framelayout);         setfragment(tag_fragment_b, r.id.main_framelayout);     }      private fragment setfragment( string tagfragment, int containerviewid) {         fragmenttransaction ftransaction = fragmentmanager.begintransaction();         fragment mfragment = null;         if(tagfragment.equals(tag_fragment_a))      mfragment = setfragmenta(ftransaction, containerviewid);         else if(tagfragment.equals(tag_fragment_b)) mfragment = setfragmentb(ftransaction, containerviewid);         else if(tagfragment.equals(tag_fragment_c)) mfragment = setfragmentc(ftransaction, containerviewid);         else if(tagfragment.equals(tag_fragment_d)) mfragment = setfragmentd(ftransaction, containerviewid);         ftransaction.addtobackstack(null);         ftransaction.commit();         return mfragment;     }      private fragment setfragmenta(fragmenttransaction ftransaction, int containerviewid) {         fragmenta fragment = (fragmenta) fragmentmanager.findfragmentbytag(tag_fragmenta);         if (fragment == null) {             fragment = new fragmenta();             if(fragment != null)                 ftransaction.replace(containerviewid, fragment,tag_fragmenta);         }          return fragment;     }      private fragment setfragmentb(fragmenttransaction ftransaction, int containerviewid) {         fragmentb fragment = (fragmentb) fragmentmanager.findfragmentbytag(tag_fragment_b);         if (fragment == null) {             fragment = new fragmentb();             if(fragment != null)                 ftransaction.replace(containerviewid, fragment,tag_fragment_b);         }         return fragment;     }      private fragment setfragmentc(fragmenttransaction ftransaction, int containerviewid) {         fragmentc fragment = (fragmentc) fragmentmanager.findfragmentbytag(tag_fragment_c);         if (fragment == null) {             fragment = new fragmentc();             if(fragment != null)                 ftransaction.replace(containerviewid, fragment,tag_fragment_c);         }          return fragment;     }      private fragment setfragmentd(fragmenttransaction ftransaction, int containerviewid) {         fragmentd fragment = (fragmentd) fragmentmanager.findfragmentbytag(tag_fragment_d);         if (fragment == null) {             fragment = new fragmentd();             if(fragment != null)                 ftransaction.replace(containerviewid, fragment,tag_fragment_d);         }         return fragment;     }      @override     public void onupdatefragmentb() {         fragmentb fragmentb = (fragmentb) fragmentmanager.findfragmentbytag(tag_fragment_b);         if (fragmentb != null) {             fragmentb.setdata(...);         }       }      @override     public void onupdated() {         fragmentmanager fragmentmanager = getfragmentmanager();         fragmentd fragment = (fragmentd) fragmentmanager.findfragmentbytag(tag_fragment_d);         fragment.setdata();     }      @override     public void changefragments() {         fragmentd fragmentd = (fragmentd) setfragment(tag_fragment_d, r.id.main_framelayout);         if(fragmentd != null)             fragmentd.setdata(...);          fragmentc fragmentc = (fragmentc) setfragment(tag_fragment_c, r.id.top_framelayout);         if(fragmentc != null)             fragmentc.setdata(...);     }       @override     public void onupdatefragmentsab {         fragmentmanager fragmentmanager = getfragmentmanager();         fragmentb fragmentb =(fragmentb) fragmentmanager.findfragmentbytag(tag_fragment_b);         if(fragmentb != null)             fragmentb.setdata(...);         fragmenta fragmenta = (fragmenta) fragmentmanager.findfragmentbytag(tag_fragment_a);         if(fragmenta != null)             fragmenta.setdata(...);      } } 

you need replace both fragments @ time come previous one, .

 public void setfragment(fragment topfrag, fragment bottomfrag){         fragmentmanager fragmentmanager=getfragmentmanager();         fragmenttransaction transaction=fragmentmanager.begintransaction();         transaction.replace(r.id.frag_top, topfrag);         transaction.replace(r.id.frag_bottom, bottomfrag);         transaction.addtobackstack(null);         transaction.commit();     }