Recyclerview not call any Adapter method :onCreateViewHolder,onBindViewHolder,

Question

my RecyclerView do not call onCreateViewHolder, onBindViewHolder, therefore, does not appear nothing in recyclerview. I put logs for debugging, and no log is shown. What can be?

My adapter:

public class CommentListAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>{
private static final int EMPTY_VIEW = 10 ;
private ArrayList<comment> mItems;
Boolean firstTime = true;
private Typeface mTf = null;
Context mContext;
public CommentListAdapter(Context context,ArrayList<comment> items){
    Log.e("Adapter", "constructor Called");
    this.mItems = items;
    mContext = context;
}
public class EmptyViewHolder extends RecyclerView.ViewHolder {
    public EmptyViewHolder(View itemView) {
        super(itemView);
    }
}
public class ViewHolder extends RecyclerView.ViewHolder{
    TextView mAuthorName;
    TextView mMessage;
    NetworkImageView mThumbnail;
    public ViewHolder(View itemView) {
        super(itemView);
        mAuthorName = (TextView)itemView.findViewById(R.id.author_name);
        mMessage = (TextView)itemView.findViewById(R.id.message);
        mThumbnail = (NetworkImageView)itemView.findViewById(R.id.author_avatar);
    }

}

public void add(comment item, int position) {
    mItems.add(position, item);
    notifyItemInserted(position);
}

public void remove(comment item) {
    int position = mItems.indexOf(item);
    mItems.remove(position);
    notifyItemRemoved(position);
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType){
    Log.e("Adapter", "onCreateViewHolder Called");
    View v;
    if(firstTime){
        mTf = BBcTypeFace.getTypeFace(parent.getContext().getApplicationContext(),"font/bbc.ttf");
        firstTime = false;
    }
    if( viewType == EMPTY_VIEW){
        v = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.comment_empty_row,parent,false);
        EmptyViewHolder evh = new EmptyViewHolder(v);
        return evh;
    }else {
        v = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.comment_row, parent, false);
        ViewHolder vh = new ViewHolder(v);
        return vh;
    }
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {
    Log.e("Adapter", "onBindViewHolder Called");
    if(viewHolder instanceof ViewHolder) {
        ViewHolder holder = (ViewHolder)viewHolder;
        comment c = mItems.get(position);
        Log.e("Adapter", "Comment is\n: " + c.toString());
        final ViewHolder finalHolder = holder;
        ImageRequest request = new ImageRequest(c.author_img_link, new Response.Listener<Bitmap>() {
            @Override
            public void onResponse(Bitmap bitmap) {
                if (bitmap != null) {
                    finalHolder.mThumbnail.setImageBitmap(bitmap);
                }
            }
        }, 0, 0, null,
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError volleyError) {
                        VolleyLog.e("ImageLoader", volleyError.getMessage());
                        VolleyLog.e("ImageLoader", volleyError.getStackTrace());
                    }
                });
        GetVideoInfo.getInstance(mContext.getApplicationContext()).addToRequestQueue(request);
        holder.mAuthorName.setText(c.author_name);
        holder.mMessage.setText(c.Message);
        holder.mMessage.setTypeface(mTf);
        holder.mAuthorName.setTypeface(mTf);
    }
}
@Override
public int getItemCount() {
    Log.e("Adapter", "getItemCount() Called");
    return (mItems.size() > 0 ? mItems.size() : 1);
}
@Override
public int getItemViewType(int position) {
    Log.e("Adapter", "getItemViewType() Called");
    if (mItems.size() == 0) {
        return EMPTY_VIEW;
    }
    return super.getItemViewType(position);
}}

I will use public void add(comment item, int position){...} to add item in RecyclerView.

in Fragment :

private RecyclerView mRecyclerView;
private CommentListAdapter mAdapter;
private LayoutManager mLayoutManager;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.fragment_item_detail, container, false);
....

    mLayoutManager = new LinearLayoutManager(getActivity());
    mAdapter = new CommentListAdapter(getActivity(),new ArrayList<comment>());
    mRecyclerView = (RecyclerView)rootView.findViewById(R.id.comment_list);
    mRecyclerView.setHasFixedSize(true);
    mRecyclerView.setLayoutManager(mLayoutManager);
    mRecyclerView.setAdapter(mAdapter);
    mRecyclerView.setItemAnimator(new DefaultItemAnimator());

    makeJsonObjectRequest(mItem.url);
    return rootView;
}

XML Files :

<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/scrollView"
    android:background="@android:color/white"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"

    android:layout_alignParentBottom="true">

    ....
        <RelativeLayout
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:layout_width="match_parent"
            android:layout_height="match_parent">
.....

            <android.support.v7.widget.RecyclerView
                android:id="@+id/comment_list"
                android:layout_width="match_parent"
                android:layout_height="match_parent">

            </android.support.v7.widget.RecyclerView>
....
        </RelativeLayout>
    ....
</ScrollView>

comment_row xml file :

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    android:orientation="horizontal"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent" android:layout_height="wrap_content"
android:gravity="right"
android:background="@android:color/darker_gray">

<LinearLayout
        android:orientation="vertical"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
    android:gravity="right">

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:id="@+id/author_name"
            android:layout_alignParentTop="true"
            android:layout_toLeftOf="@+id/author_avatar"
            android:layout_toStartOf="@+id/author_avatar"
            android:gravity="right" />

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/message"
            android:layout_below="@+id/author_name"
            android:layout_toLeftOf="@+id/author_avatar"
            android:layout_toStartOf="@+id/author_avatar"
            android:gravity="right" />
        </LinearLayout>

<com.android.volley.toolbox.NetworkImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/author_avatar"
    android:layout_alignParentTop="true"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true"
    android:minHeight="150dp"
    android:minWidth="150dp" /></LinearLayout>

I will add item to RecyclerView with this code :

JsonObjectRequest jsonObjReqComment = new
             JsonObjectRequest(Request.Method.GET,urlJsonObj+"#comment", null,
                     new Response.Listener<JSONObject>() {
                         @Override
                         public void onResponse(JSONObject response) {
                             try {
                                 JSONArray res = response.getJSONArray("response");
                                 //Log.e("Comment","Count:"+response.toString());
                                 //Log.e("Comment","Count:"+res.length());
                                 for (int i = 0; i < res.length(); i++) {
                                     JSONObject thread = res.getJSONObject(i);
                                     JSONObject author_json = thread.getJSONObject("author");
                                     int dislikes = thread.getInt("dislikes");
                                     int likes = thread.getInt("likes");
                                     String Message = thread.getString("message");
                                     //get Author info
                                     String author_img_link = author_json.getJSONObject("avatar").getString("permalink");
                                     String author_name = author_json.getString("name");
                                     comment c = new comment(dislikes,likes,Message,author_img_link,author_name);
                                     //Log.e("Comment",c.toString());
                                     //commentsList.add(c);
                                     mAdapter.add(c,0);
                                 }

                             } catch (JSONException e) {
                                 Log.e("OnResponse","Error JSON");
                                 e.printStackTrace();
                             } catch (Exception e){
                                 Log.e("OnResponse","Error Exception");
                                 e.printStackTrace();
                             }


                         }
                     }
                     , new Response.ErrorListener() {
                 @Override
                 public void onErrorResponse(VolleyError error) {
                     VolleyLog.d("vOLLEY", "Error: " + error.getMessage());
                     // hide the progress dialog

                 }
             }
             ){
                 @Override
                 public Map<String, String> getHeaders(){
                     Map<String, String> headers = new HashMap<String, String>();
                     headers.put("User-agent", "Comment");
                     return headers;
                 }
             };

A row matching parent on both width and height? Are you sure you want that? — Pedro Oliveira, Jan 23 '15 at 17:53
You are not even getting getItemCount ? That is quite weird. Besides that, your empty view implementation is wrong. When you add an item for the first time, you should first call notifyItemRemoved(0) so that RV knows item 0 is removed. Also, your getItemViewType implementation is quite risky as RV may call it while EMPTY view is a part of the UI but new items are just added so this is quite risky. I would suggest to have a boolean in your adapter that sets shouldEmpty view and when it is set to false, you should call notifyItemRemoved(0). Make sure it happens before adding items . — yigit, Jan 23 '15 at 18:21
@PedroOliveira I changed to android:layout_width="match_parent" android:layout_height="wrap_content" , dosen't change any thing — SanatiSharif, Jan 23 '15 at 18:22
@yigit RecyclerView just call getItemCount(), but RecyclerView don't call other Override methods, I try this code without EmptyViewHolder with Initial data, but I have this problem too, excuse me, if my english is poor — SanatiSharif, Jan 23 '15 at 18:27
So not even a call to onCreate or onBind for EMPTY View? also, did you debug if `add` is being called? — yigit, Jan 23 '15 at 18:31
I think when getItemCount() returns 0, it wont call other methods. Can you show us the part where you're actually adding items to the adapter ? — Shivam Verma, Jan 23 '15 at 18:36
@ShivamVerma getItemCount() return >= 1, I will update my question. — SanatiSharif, Jan 23 '15 at 18:39
I think, the problem is with this line : `mAdapter.add(c,0);` You're always adding the item at the 0th position which tells android that the item at position at 0 has changed and it tries to just redraw the 0th item position. Can you try adding something like `mAdapter.add(c,i);` — Shivam Verma, Jan 23 '15 at 18:48
@ShivamVerma, nope, calling add(c, 0) only means it will add the new item to position 0 and push other items down (so empty view moves to position 1). — yigit, Jan 23 '15 at 18:50
@SanatiSharif, if you can upload a sample project, i'm happy to take a look at it. — yigit, Jan 23 '15 at 18:52
@yigit Is there a possibility of Wrong Thread Exception ? Given that `mAdapter.add(c,0);` is possibly being called from a background thread and the `notifyItemInserted()` method needs to run on the UI thread ? — Shivam Verma, Jan 23 '15 at 18:55
@ShivamVerma nope, Volley onResponse run on main (UI) Thread — SanatiSharif, Jan 23 '15 at 19:28
Ok, one last thing. Check the height of your RV. Try setting a fixed height. Maybe the combination of ScrollView, RL and RV causes it to have 0 height (which would explain not getting any views because there is no room). I don't understand why you have that setup anyways. Besides that, I cannot see what else is going wrong. If there was a bug in RV like this, it would be pretty obvious and surface itself way before. — yigit, Jan 23 '15 at 19:37
@yigit excuse me I'm new in android programing, what is RL and RV ? Thanks, — SanatiSharif, Jan 23 '15 at 20:04
Always specify layout manager. I keep forgetting about that! — user3025587, Jan 02 '20 at 06:31

AAnkit · Answer 1 · 2017-10-30T19:57:30.973

192

Other than @SanatiSharif's and @sohrab's answer, you have to follow below mandatory step.

Make sure you call setLayoutManager, something like below.

recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));

before setting adapter into recyclerView, otherwise it is not going to work. You can customize it if you need. this link will give you some idea of how LayoutManager works.

edited Oct 30 '17 at 19:57

answered Apr 07 '16 at 23:28

AAnkit

27,299
12
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29

This answer deserves more votes. I ALWAYS forget this. – Can Poyrazoğlu Jun 03 '16 at 10:46
6

Same here, I forget this all the time and then I search for what I couldve done wrong and then I end up here lol. – Ruben2112 Jul 12 '16 at 14:08
3

the question is, why is this needed? This answer solves my problem but I don't know why. – Ben Aug 31 '16 at 22:34
Thanks.That was really helpful. – Siva Prakash Dec 06 '16 at 20:06
1

You can also set this via XML: app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager" – Westy92 Aug 09 '18 at 16:28
1

The amount of times I've ended up back at this answer (o_-) – luca992 Aug 09 '19 at 01:29

score 36 · Accepted Answer · edited Sep 08 '15 at 15:28

36

As @yigit guess the combination of ScrollView, RelativeLayout causes this problem, Just make more room for RecyclerView.

edited Sep 08 '15 at 15:28

Prudhvi

2,276
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answered Jan 23 '15 at 22:03

sohrab Aboozarkhani Fard

376
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4

1

Thanks. Preview the xml to ensure that the recycle view is displayed. – blaffie May 07 '15 at 19:33
2

Mine is not inside a ScrollView, yet still having this problem. – IgorGanapolsky Sep 24 '15 at 16:33
I had my RecyclerView inside ConstraintLayout so it was not calling any adapter methods. Crazy :x – Saraz Oct 19 '16 at 14:50

score 19 · Answer 3 · edited May 23 '17 at 12:10

If RecyclerView gets put into a ScrollView, then during measure step its height is unspecified (because ScrollView allows any height) and gets equal to minimum height (as per implementation) which is apparently zero.

ref : android: RecyclerView inside a ScrollView

Solution : - put views in row of RecyclerViews - Calculate the size of the list items and set the height of the ListView programmatically http://vardhan-justlikethat.blogspot.com/2014/04/android-listview-inside-scrollview.html

score 7 · Answer 4 · answered Nov 10 '17 at 00:42

7

Might have been a different case but for me I just forgot to set the Layout Manager as follows:

LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
recycler.setLayoutManager(layoutManager);

Hope it helps :)

answered Nov 10 '17 at 00:42

gmartinsnull

1,075
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score 6 · Answer 5 · answered May 04 '17 at 06:14

Its late but hope it will help somone. try either of the following:

first solution: make sure you haven't use this line unnecessarily

recyclerView.setHasFixedSize(true);

second solution: make sure you set layout manager to recyclerView

recycler.setLayoutManager(new LinearLayoutManager(this));

third solution: you getItemCount returns 0, So RecyclerView never tries to instantiate a view. Make it return something greater than 0

score 3 · Answer 6 · answered Jun 02 '18 at 11:48

In my Case I was using Fragment-> ViewPager and Tablayout -> Inside viewpagers item I used RecyclerView.

So Instead of calling ViewPagerAdapter(getChildFragmentManager()) , I was calling ViewPagerAdapter(getSupportFragmentManager()) , that is why any of my recycler adapter item is not getting called.

So proper way to set the ViewPagerAdapter within a fragment is

ViewPagerAdapter(getChildFragmentManager())

score 1 · Answer 7 · answered Jul 31 '17 at 04:41

In my case i had this structure

<ScrollView>
    <RelativeLayout>
        <android.support.v7.widget.RecyclerView/>

    </RelativeLayout>
</ScrollView>

i solved the problem remove Relative

<ScrollView>

        <android.support.v7.widget.RecyclerView/>

</ScrollView>

score 1 · Answer 8 · answered Jul 18 '18 at 15:30

Is kind of silly, but another thing that can block the calls to the methods is to declare the visibility of the view as GONE.

android:visibility="gone"

recyclerView.setVisibility(View.GONE);

Any of these will block the call of the methods in RecyclerView.Adapter

I hope it can help someone.

score 1 · Answer 9 · answered Jun 23 '21 at 09:57

I had a similar issue but none of the above answers helped me.

Finally, I found out I made a mistake when creating and binding the view for the Fragment in which my RecyclerView was living:

Problematic Code

FormPageFragment.onCreate

binding=FormPageBinding.inflate(layoutInflater)

but in onCreateView I did this:

FormPageFragment.onCreateView

return inflater.inflate(R.layout.form_page, container, false)

and later in onStart setting the adapter like this:

FormPageFragment.onStart

binding.formContent.adapter=FormEntriesAdapter(page, viewModel.enteredData)

Solution

But this was rubbish. It should have all be done in onCreateView and of course the binding.rootView needs to be returned as view, other wise the bindings views are not attached to the layout and setting any adapters on them has no effect.

working version of onCreateView

 binding=FormPageBinding.inflate(layoutInflater)
 return binding.root

So it was more a problem with fragment instanciation, creating and binding the correct views than with the RecyclerView itself.

Recyclerview not call any Adapter method :onCreateViewHolder,onBindViewHolder,

9 Answers9

Problematic Code

Solution

Linked

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