Solution for this issue is use FirebaseIndexRecyclerAdapter instead of FirebaseRecyclerAdapter.
Link: https://github.com/firebase/FirebaseUI-Android/blob/master/database/README.md#using-firebaseui-with-indexed-data
Step by Step:
First-> maintain post of every user in a node let say "My_Challenges":

So whenever a user post anything, copy that post id under user uid inside this node too.
Second-> Maintain another node for posts which you can see(in my case i want to see only my friends posts) let say "timelineIndex":

Let say User 1(1014382358695053) and User 2(10207254337991322) are friend. So copy all post id from My_Challenges of User 1 to timelineIndex of User 2 and vice versa also. (NOTE : You have to do this every time a new post id comes under your uid copy it to your friend uid under timelineIndex)
Finally-> Use FirebaseIndexRecyclerAdapter :
As in above given link, use
keyRef = databaseReference.child("timelineIndex").child(mUserId);
dataRef = databaseReference.child("Blogs");
That's it. I hope it helps.