RecyclerView.onBindViewHolder called only once

Question

After many hours of researching I am finally consulting official help.

I have a RecyclerView.Adapter and RecyclerView.ViewHolders that worked perfectly. But for some reasons I do not understand, RecyclerView.Adapter.onBindViewHolder is not called properly.

    private class AttendeeAdapter extends RecyclerView.Adapter<AttendeeHolder> {     /*FIELDS*/     private List<Attendee> mAttendeeList;      /*CONSTRUCTORS*/     public AttendeeAdapter(List<Attendee> attendees) {         mAttendeeList = attendees;         //Log.i(TAG, "AttendeeAdapter size: " + getItemCount());     } 

Based on the Log message (the item count as the size of the list as expected), I assume the AttendeeAdapter was properly instantiated.

So I expect onBindViewHolder(VH, int) method would be called as many times as the size of the List but it is not. The method is called only ONCE!

    /*METHODS*/     @Override     public AttendeeHolder onCreateViewHolder(ViewGroup parent, int viewType) {         LayoutInflater layoutInflater = LayoutInflater.from(getActivity());         View itemView = layoutInflater.inflate(R.layout.list_attendee, parent, false);         return new AttendeeHolder(itemView);     }      @Override     public void onBindViewHolder(AttendeeHolder holder, int position) {         Attendee attendee = mAttendeeList.get(position);         holder.bindAttendee(attendee, position);          Log.i(TAG, "Binding ViewHolder #" + position);         /* Binding ViewHolder #0 and that's it */     }      @Override     public int getItemCount() {         return mAttendeeList.size();     } } 

My AttendeeHolder (extending RecyclerView.ViewHolder) goes as the following:

    private class AttendeeHolder extends RecyclerView.ViewHolder {     /*FIELDS*/     private EditText mAttendeeNameEditText;     private Attendee mAttendee;      /*CONSTRUCTOR*/     public AttendeeHolder(View itemView) {         super(itemView);         mAttendeeNameEditText = (EditText) itemView.findViewById(R.id.edit_text_list_item);         mAmountEditTextList = new ArrayList<>(eventMaxCount);       }      /*METHODS*/     public void bindAttendee(Attendee attendee, final int position) {         mAttendee = attendee;         String attendeeName = mAttendee.getName();          // Set the name to the EditText if a name has already been set         if (attendeeName != null) {             mAttendeeNameEditText.setText(attendeeName);         }     } } 

and implemented in the main code as

List<Attendee> attendees = AttendeeLab.get().getAttendeeList();      mAttendeeAdapter = new AttendeeAdapter(attendees);      mAmountRecyclerView.setAdapter(mAttendeeAdapter); 

I guess the code would work (I think I have not made any change) but the gradle dependencies might not be properly set. That was where I tried modifying recyclerview-v7:23.3.0 to recyclerview-v7:23.1.0 or whatever (None of them worked).

dependencies { compile fileTree(dir: 'libs', include: ['*.jar']) testCompile 'junit:junit:4.12' compile 'com.android.support:appcompat-v7:23.3.0' compile 'com.android.support:design:23.3.0' compile 'com.android.support:support-v4:23.3.0' compile 'com.android.support:recyclerview-v7:23.1.2' } 

Any help or comment would be appreciated. I wish I would be saying good bye to the headache after several hours from now.

Answer 1

The problem is not in your code. Make sure you set layout_height to wrap_content of RecyclerView child item.

Answer 2

Take care of the onBindViewHolder behaviour in the RecyclerView cycles. RecyclerView.ViewHolder position 0 itemView

android:layout_height="match_parent" 

occupies the current displayed screen. Scroll and onBindViewHolder should be triggered but make sure getItemCount was set appropriately.

Solution:

android:layout_height="wrap_content" 

Solution with ConstraintLayout as inflated itemView:

<?xml version="1.0" encoding="utf-8"?>     <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:app="http://schemas.android.com/apk/res-auto"     xmlns:tools="http://schemas.android.com/tools"     android:layout_width="match_parent"     android:layout_height="wrap_content"><!-- IMPORTANT -->     <!-- ... --> </android.support.constraint.ConstraintLayout>