android - Set tab's title from fragment on the fly -

i have on activity (mainactivity) , has 5 tabs, each tab contains fragment. each fragment contains edittext widget. i'd set active tab's title when change text of edittext in active fragment's class. how on fly ? here resources:

mainactivity:

public class mainactivity extends appcompatactivity {     private sectionspageradapter msectionspageradapter;     private viewpager mviewpager;      imageview imageview;      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);          toolbar toolbar = (toolbar) findviewbyid(r.id.toolbar);         setsupportactionbar(toolbar);         msectionspageradapter = new sectionspageradapter(getsupportfragmentmanager());          mviewpager = (viewpager) findviewbyid(r.id.container);         mviewpager.setadapter(msectionspageradapter);          tablayout tablayout = (tablayout) findviewbyid(r.id.tabs);         tablayout.setupwithviewpager(mviewpager);          floatingactionbutton fab = (floatingactionbutton) findviewbyid(r.id.fab);         fab.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view view) {                 snackbar.make(view, "replace own action", snackbar.length_long)                         .setaction("action", null).show();             }         });      }     @override     public boolean oncreateoptionsmenu(menu menu) {         getmenuinflater().inflate(r.menu.menu_main, menu);         return true;     }     @override     public boolean onoptionsitemselected(menuitem item) {         int id = item.getitemid();         if (id == r.id.action_settings) {             return true;         }          return super.onoptionsitemselected(item);     } } 

sectionpageradapter:

public class sectionspageradapter extends fragmentpageradapter {      public sectionspageradapter(fragmentmanager fm) {         super(fm);     }      @override     public fragment getitem(int position) {         switch (position){             case 0:                 tab1 tab1 = new tab1();                 return tab1;             case 1:                 tab2 tab2 = new tab2();                 return tab2;             case 2:                 tab3 tab3 = new tab3();                 return tab3;             case 3:                 tab4 tab4 = new tab4();                 return tab4;             case 4:                 tab5 tab5 = new tab5();                 return tab5;             default:                 return null;         }     }      @override     public int getcount() {         // show 5 total pages.         return 5;     }      @override     public charsequence getpagetitle(int position) {         switch (position) {             case 0:                 return "title1";             case 1:                 return "title2";             case 2:                 return "title3";             case 3:                 return "title4";             case 4:                 return "title5";         }         return null;     } } 

tab1:

public class tab1 extends fragment {      @override     public view oncreateview(layoutinflater inflater, viewgroup container,                              bundle savedinstancestate) {         view rootview = inflater.inflate(r.layout.tab1, container, false);         return rootview;     } } 

these generated android studio, guess should go here. want, if have edittext on tab1, , start type in it, changes first tab's title "title1" string typed.

from edittext should use addtextchangedlistener on edittext within textwatcher instance change title on fly. refer code.

edittext.addtextchangedlistener(new textwatcher() {         @override         public void beforetextchanged(charsequence charsequence, int i, int i1, int i2) {          }          @override         public void ontextchanged(charsequence charsequence, int i, int i1, int i2) {             //this tab index want change title of..             tablayout.gettabat(1).settext(charsequence);         }          @override         public void aftertextchanged(editable editable) {          }     }); 

hope helps..

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