android - How to set tab at position 1 in viewpager -

i've 2 tabs. default 0's position tab selected wan select tab @ 1st position. i've tried

tablayout tablayout = (tablayout) findviewbyid(r.id.tabs); tablayout.tab tab = tablayout.gettabat(someindex); tab.select(); 

also didn't work. search on stackoverflow , apply @ position 1 app crashed.

    tablayout = (tablayout) findviewbyid(r.id.tab_layout);             tablayout.addtab(tablayout.newtab().settext("add expense"));             tablayout.addtab(tablayout.newtab().settext("add ledger"));              final viewpager viewpager = (viewpager) findviewbyid(r.id.pager2);             final tabadapter adapter = new tabadapter(getsupportfragmentmanager(), tablayout.gettabcount());              viewpager.setadapter(adapter);             viewpager.addonpagechangelistener(new tablayout.tablayoutonpagechangelistener(tablayout));   tablayout.gettabat(1).select();  //        }         tablayout.addontabselectedlistener (new tablayout.ontabselectedlistener() {             @override             public void ontabselected(tablayout.tab tab) {                 viewpager.setcurrentitem(tab.getposition());              }              @override             public void ontabunselected(tablayout.tab tab) {              }              @override             public void ontabreselected(tablayout.tab tab) {              }         });     } 

tabadapter:

class tabadapter extends fragmentstatepageradapter {     private int mnumoftabs;      tabadapter(fragmentmanager fm, int numoftabs) {         super(fm);         this.mnumoftabs = numoftabs;     }      @override     public fragment getitem(int position) {          switch (position) {              case 0:                 return new addexpensefragment();              case 1:                 return new addledgerfragment();          }         return null;     }      @override     public int getcount() {         return mnumoftabs;     } } 

try viewpager.setcurrentitem(pos);