Android - getSupportFragmentManager returns null -

i trying specific instance of fragment using it's tag, using viewpager, makes things difficult. used:

public fragment getfragmentbyposition(int pos) {     string tag = "android:switcher:" + r.id.pager + ":" + pos;     fragmentmanager fragmentmanager = this.getsupportfragmentmanager();     fragment fragment = fragmentmanager.findfragmentbytag(tag);     return fragment; } 

to find fragment, getsupportfragmentmanager returning null.

the above method in activity, outside of viewpager adapter class, , lost here. highly appreciated, thanks!

you can use smartviewpager here https://gist.github.com/jacek-marchwicki/d6320ba9a910c514424d

extend view pager class , fragment using getactivefragment method. can change implementation of method fragment tag name.

public fragment getactivefragment(string name) {     final fragment fragmentbytag = fragmentmanager.findfragmentbytag(name);     if (fragmentbytag == null) {         final bytearrayoutputstream outputstream = new bytearrayoutputstream();         fragmentmanager.dump("", null, new printwriter(outputstream, true), null);         final string s = new string(outputstream.tobytearray(), charsets.utf_8);         throw new illegalstateexception("could not find fragment via hacky way.\n" +                 "we looking name: " + name + "\n" +                 "fragment name not exists, or hack stopped working.\n" +                 "current fragment manager dump is: " + s);     }     return fragmentbytag; }