活动开始使用Linearlayoutmanager时，将Recycleview滚动到顶部位置

Question

I"m retrieving Firebase RealTime Database to my Recycleview Adapter Class . I want to sort the data by date with latest post at top. I'm using

llm.setReverseLayout(true);

which works but now when activity opens then recycleview automatically scrolls to bottom itself. But I want it to force it to Top.

Here is my Code

  rv.setHasFixedSize(true); LinearLayoutManager llm = new LinearLayoutManager(this); llm.setReverseLayout(true); rv.setLayoutManager(llm); llm.scrollToPositionWithOffset(0, 0); rv.setAdapter(staggeredBooksAdapter); 

My whole code is

 public class SubjectBooks extends AppCompatActivity { FirebaseAuth fauth; String user; DatabaseReference dbreference,dbref; RecyclerView rv; String subject; int child_count=0; ArrayList<Books> list; SubjectBooksAdapter staggeredBooksAdapter; ProgressDialog progressDialog; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_subject_books); getSupportActionBar().setTitle(getIntent().getStringExtra("subject")+" Area"); getSupportActionBar().setBackgroundDrawable( new ColorDrawable(Color.parseColor("#8abe50"))); // this.getSupportActionBar().setDisplayHomeAsUpEnabled(true); // this.getSupportActionBar().setHomeAsUpIndicator(R.drawable.ic_menu_share); fauth = FirebaseAuth.getInstance(); subject = getIntent().getStringExtra("subject").trim(); dbreference = FirebaseDatabase.getInstance().getReference("books").child(subject); dbreference.keepSynced(true); user = fauth.getCurrentUser().getEmail(); list = new ArrayList<>(); staggeredBooksAdapter = new SubjectBooksAdapter(list); rv = (RecyclerView) findViewById(R.id.recyclerView); final ProgressDialog progressDialog = ProgressDialog.show(this, "Loading...", "Please wait...", true); progressDialog.setMessage("Please wait ..."); progressDialog.setCanceledOnTouchOutside(true); progressDialog.show(); rv.setHasFixedSize(true); LinearLayoutManager llm = new LinearLayoutManager(this); rv.setLayoutManager(llm); rv.setAdapter(staggeredBooksAdapter); dbreference.addChildEventListener(new ChildEventListener() { @Override public void onChildAdded(DataSnapshot dataSnapshot, String s) { final Books b1 = dataSnapshot.getValue(Books.class); // Log.e("Value is ",dataSnapshot.getKey()+" "+b1.getBauthor()); //Log.e("Book"," received"); if(!user.equals(b1.getSelleremail()) || (user.equals(b1.getSelleremail())) ) { child_count++; list.add(b1); staggeredBooksAdapter.notifyDataSetChanged(); progressDialog.dismiss(); } } 

I used

/Solution one
mLayoutManager.scrollToPositionWithOffset(0, 0);
//Solution Two
rv.scrollToPosition(0)
//Solution Three
setStackFromEnd(false)
//Solution Four
Collections.reverse();

But they didn't work.

Any Solution? Thanks in advance.

Answer 1

Don't use set anything out of the box now pass false to llm.setReverseLayout(false);

When you get the data from firebase just use Collections.reverse(passyourlist); the list would be reversed inplace. After that pass it to your adapter and it would work fine.