Recyclerview does not show anything?

user_8719521 0
Viewed 2906

I'm trying to show list of strings in recycler view. For some reason it is not working. it does not show anything. I dont know why it is not working, its not the first time that i use that, usally i did it with firebase recycler.

Here is my code

   rvTypeMusic = (RecyclerView)findViewById(R.id.rvMusicType);
    ArrayList<String> songs = new ArrayList<String>();
    songs.add("PHP");
    songs.add("C#");
    songs.add("Java");
    songs.add("JavaScript");
    songs.add("Android");

   adapter = new TypeMusicListAdapter(this,songs);
    rvTypeMusic.setAdapter(adapter);
    rvTypeMusic.setLayoutManager(new GridLayoutManager(this,2));
}


     public static class TypeMusicListAdapter extends 
              RecyclerView.Adapter<TypeMusicListViewHolder>{
    private LayoutInflater inflater;
    private Context context;
    private List<String> data;

    public TypeMusicListAdapter(Context context, List<String> data){
        this.context = context;
        this.inflater = LayoutInflater.from(context);
        this.data = data;
    }

    @Override
    public TypeMusicListViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = inflater.inflate(R.layout.type_music_item,parent,false);
        return new TypeMusicListViewHolder(v);
    }

    @Override
    public void onBindViewHolder(TypeMusicListViewHolder holder, int position) {
        String songType = data.get(position);
        //holder.musicType.setText(songType.getSongName());
        holder.musicType.setText(songType);
    }

    @Override
    public int getItemCount() {
        return 0;
    }
}

public static class TypeMusicListViewHolder extends RecyclerView.ViewHolder {
    private TextView musicType;

    public TypeMusicListViewHolder(View itemView) {
        super(itemView);
        musicType = (TextView) itemView.findViewById(R.id.musicType);
    }
}

XML File

      <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="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.world.bolandian.talent.MainActivity"
tools:showIn="@layout/app_bar_main">

<android.support.v7.widget.RecyclerView
    android:id="@+id/rvMusicType"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:layout_marginBottom="0dp"
    android:layout_marginLeft="0dp"
    android:layout_marginRight="0dp"
    android:layout_marginTop="0dp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    tools:listitem="@layout/type_music_item">

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

XML Item

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

<android.support.v7.widget.CardView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">


    <TextView
        android:id="@+id/musicType"
        android:padding="25dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView"
        android:textAppearance="@style/TextAppearance.AppCompat.Display1" />
</android.support.v7.widget.CardView>

</LinearLayout>

What am i missing here? i have tried few things but nothing worked.

android-recyclerview android java
3 Answers

the answer is mixture of both @abdur Rahman and @ADM's . First we must set the Layout Manager to RecyclerView before setting the adapter like this.

rvTypeMusic.setLayoutManager(new GridLayoutManager(this,2));
rvTypeMusic.setAdapter(adapter);

because the recycler view will start laying the views as soon as we set the adapter so it must have the layout manager by then. Secondly, this

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

onCreateViewHolder and onBindViewHolder is called only when it returns non zero value

user_58603720

Problem is in this line.

 @Override
public int getItemCount() {
    return 0;
}

It should be 

 @Override
public int getItemCount() {
    return data.size();
}
user_41686070

Add this line in after initializing recycle view.

rvTypeMusic.setLayourManager(new LinearLayoutManager());

It will work then.

user_87069890
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