RecyclerView does not scroll & Won't display large numbers

Question

I am having a bit trouble with my RecyclerView. If my adapter list have more than 20 items, the recyclerview shows nothing. Anything <20 is ok, and the items are displayed. Also, I can't scroll on the recyclerView.

RecyclerView creation in Fragment:

recyclerView.setHasFixedSize(true);
layoutManager = new LinearLayoutManager(context);
recyclerView.setLayoutManager(layoutManager);
myAdapter = new MyAdapter();
myAdapter.setList(myList); //ArrayList<MyObject>
recyclerView.setAdapter(myAdapter);

My Adapter:

public class MyAdapter extends RecyclerView.Adapter<MyViewHolder> {

    private final ArrayList<MyObject> myList = new ArrayList<MyObject>();

    public MyAdapter() {}

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.my_item, parent, false);
        return new MyAdapter(v);
    }

    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
        holder.bind(myList.get(position));
    }

    @Override
    public int getItemCount() {
        return myList.size();
    }

    public void setList(ArrayList<MyObject> newList) {
        myList.clear();
        myList.addAll(newList);
        notifyDataSetChanged();
    }
}

and here is my viewholder:

public class CountryViewHolder extends RecyclerView.ViewHolder {

    private final TextView textView;
    private MyObject object;

    public CountryViewHolder(@NonNull View itemView) {
        super(itemView);
        textView = itemView.findViewById(R.id.my_holder_textview);
    }

    public void bind(@Nullable MyObject object){
        this.object = object;
        if(pbject == null)
            textView.setText("Error. Could not load name.");
        else
            textView.setText(object.getName());
    }
}

myitem.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:id="@+id/my_holder_textview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text=""
        android:layout_marginBottom="4dp"
        android:textSize="24sp"
        android:gravity="center"/>
</LinearLayout>

Fragment layout where I have the recyclerView:

<androidx.constraintlayout.widget.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="match_parent">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/myRecyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginBottom="8dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

Any suggestions?

EDIT:

Changing the layout from ConstraintLayout to LinearLayout, the recyclerview will run fine as it should. So the culprit here is the Constraintlayout. I would like to keep the constraintlayout, but I can't figure out how to make it work yet.

What do you mean with disappear,is it outside the view or non existent? Have you tried using the layout inspector? https://developer.android.com/studio/debug/layout-inspector — Haroun Hajem, Mar 25 '19 at 18:37
The layout inspector could give you some clues what is going on. It sound like an layout issue. You need to find the culprit, is it the RecyclerView, ListItem, Fragement? — Haroun Hajem, Mar 25 '19 at 18:42
@HarounHajem I can see that, when having large lists, my framelayout(this is the fragment container from activity)+constraintlayout(in fragment layout)+recyclerview has not expanded at all horizontally, but vertically. It shows up like "line" in the inspector. Any Idea why? — CJR, Mar 25 '19 at 18:46

score 0 · Answer 1 · answered Mar 25 '19 at 18:28

0

Instead of:

<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/myRecyclerView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"

Try:

<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/myRecyclerView"
    android:layout_width="0dp"
    android:layout_height="0dp"

answered Mar 25 '19 at 18:28

MidasLefko

4,499
1
31
44

Thanks for your reply. I have tried this, I end up getting an empty recyclerview even if mylist is <20 items big – CJR Mar 25 '19 at 18:42

Haroun Hajem · Answer 2 · 2019-03-26T13:51:41.313

0

I can see that you have an error in onCreateViewHolder, it should return MyViewHolder and not a MyAdapter.

Also the setHasFixedSize(true) could be an issue here because your children might not change in size if this has to be true(find more information on SO).

edited Mar 26 '19 at 13:51

answered Mar 25 '19 at 20:13

Haroun Hajem

5,223
3
26
39

1

Also view holder class name is "CountryViewHolder" not "MyViewholder". – Brijesh Kumar Mar 26 '19 at 06:05

RecyclerView does not scroll & Won't display large numbers

2 Answers2