javaRecyclerview什么都不显示？

我正在尝试在回收站视图中显示字符串列表.由于某种原因,它不起作用.它什么也没显示.
我不知道为什么它不起作用,这不是我第一次使用它,通常我是用Firebase Recycler做到的.

这是我的代码

rvTypeMusic = (RecyclerView)findViewById(R.id.rvMusicType);
ArrayList sOngs= new ArrayList();
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{
private LayoutInflater inflater;
private Context context;
private List data;
public TypeMusicListAdapter(Context context, List 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文件

xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_
android:layout_
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:cOntext="com.world.bolandian.talent.MainActivity"
tools:showIn="@layout/app_bar_main">
android:id="@+id/rvMusicType"
android:layout_
android:layout_
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">




XML项目

android:layout_
android:layout_
android:orientation="vertical">
android:layout_
android:layout_>
android:id="@+id/musicType"
android:padding="25dp"
android:layout_
android:layout_
android:text="TextView"
android:textAppearance="@style/TextAppearance.AppCompat.Display1" />




我在这里想念什么？我尝试了几件事,但没有任何效果.

解决方法:

问题在于这条线.

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


它应该是

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