title: Recyclerview does not show anything?
body: <p>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.</p>
  
  <p>Here is my code</p>
  
  <pre><code>   rvTypeMusic = (RecyclerView)findViewById(R.id.rvMusicType);
      ArrayList&lt;String&gt; songs = new ArrayList&lt;String&gt;();
      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&lt;TypeMusicListViewHolder&gt;{
      private LayoutInflater inflater;
      private Context context;
      private List&lt;String&gt; data;
  
      public TypeMusicListAdapter(Context context, List&lt;String&gt; 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);
      }
  }
  </code></pre>
  
  <p><strong>XML File</strong></p>
  
  <pre><code>      &lt;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"&gt;
  
  &lt;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"&gt;
  
  &lt;/android.support.v7.widget.RecyclerView&gt;
  &lt;/android.support.constraint.ConstraintLayout&gt;
  </code></pre>
  
  <p><strong>XML Item</strong></p>
  
  <pre><code>   &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical"&gt;
  
  &lt;android.support.v7.widget.CardView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"&gt;
  
  
      &lt;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" /&gt;
  &lt;/android.support.v7.widget.CardView&gt;
  
  &lt;/LinearLayout&gt; 
  </code></pre>
  
  <p>What am i missing here? i have tried few things but nothing worked.</p>