RecyclerView：没有附加适配器跳过布局（TabbedActivity + Firestore）

Question

我正在尝试从 firestore 检索数据并将其显示为 TabbedActivity 中的 RecyclerView。数据显示在每个 tab/fragment 中，但有时如果我在选项卡中向前滑动然后向后滑动，数据就会消失，并出现错误 "No adapter attached skipping layout"。

Fragment.java

public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    v = inflater.inflate(R.layout.sligo_fragment, container, false);

    recyclerView = (RecyclerView) v.findViewById(R.id.sligo_recycler);
    recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));

    return v;
}

@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    db.collection("sligo")
            .get()
            .addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
                @Override
                public void onComplete(@NonNull Task<QuerySnapshot> task) {
                    for (QueryDocumentSnapshot document : task.getResult()) {
                        placeNames.add(document.getData().get("Name").toString());
                    }
                    MyAdapter adapter = new MyAdapter(placeNames);
                    recyclerView.setAdapter(adapter);
                }
            });
}

MyAdapter.java

public static class MyViewHolder extends RecyclerView.ViewHolder{
    public TextView textView;
    public MyViewHolder(View itemView) {
        super(itemView);
        textView = itemView.findViewById(R.id.info_text);
    }
}

public MyAdapter(ArrayList<String> myDataset) {

    mDataset = myDataset;
}


@NonNull
@Override
public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    // create a new view
    View v =  LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_item, parent, false);
    MyViewHolder vh = new MyViewHolder(v);
    return vh;

}

Answer 1

根据 Fragment LifeCycle onCreate 在 onCreateView 之前调用。除此之外，您正在异步操作中设置适配器，这需要时间才能完成。尝试将代码移动到 onCreateView，如下所示：

public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    v = inflater.inflate(R.layout.sligo_fragment, container, false);

    recyclerView = (RecyclerView) v.findViewById(R.id.sligo_recycler);
    recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
    MyAdapter adapter = new MyAdapter(placeNames);
    recyclerView.setAdapter(adapter);

    db.collection("sligo")
            .get()
            .addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
                @Override
                public void onComplete(@NonNull Task<QuerySnapshot> task) {
                    for (QueryDocumentSnapshot document : task.getResult()) {
                        placeNames.add(document.getData().get("Name").toString());
                    }

                    adapter.notifyDataSetChanged();
                }
            });

    return v;
}