Recyclerview not call any Adapter method :onCreateViewHolder,onBindViewHolder,
JavaAndroidListadapterAndroid RecyclerviewJava Problem Overview
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;
}
};
Java Solutions
Solution 1 - Java
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.
Solution 2 - Java
As @yigit guess the combination of ScrollView, RelativeLayout causes this problem,
Just make more room for RecyclerView.
Solution 3 - Java
> 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 : https://stackoverflow.com/questions/25515904/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
Solution 4 - Java
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 :)
Solution 5 - Java
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
Solution 6 - Java
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())
Solution 7 - Java
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>
Solution 8 - Java
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.
Solution 9 - Java
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.