不可能：没有附加布局管理器；跳过布局

Question

我完全迷失了这个错误，我明白了，但我不知道出了什么问题。对于代码：

 // In the OnCreate of my activity
  historyRecyclerView = (RecyclerView)findViewById(R.id.recycler_suggestions);
  SearchBarHistoryAdapter searchBarHistoryAdapter = new SearchBarHistoryAdapter();
  searchBarHistoryAdapter.setActivity(this);
  historyRecyclerView.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false));
  historyRecyclerView.setAdapter(searchBarHistoryAdapter);
  searchBarDisplayManager.setTypeAdapter(SearchBarDisplayManager.SEARCH_TYPE.HISTORY, searchBarHistoryAdapter);

SearchDisplayManager 仅包含一个适配器列表。适配器：

 public class SearchBarHistoryAdapter extends SearchBarAdapter {
private ArrayList<String> historyList;
private HistoryTask historyTask;

private void setHistoryList(ArrayList<String> history) {
historyList = history;
notifyDataSetChanged();
}

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.search_list_item, parent, false);
final HistoryViewHolder historyViewHolder = new HistoryViewHolder(v);
return historyViewHolder;
}

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
  ((HistoryViewHolder) holder).bind(historyList.get(position));
}

@Override
public int getItemCount() {
return historyList == null ? 0 : historyList.size();
}

@Override
public void startSearch(String searchString) {
if(TextUtils.isEmpty(searchString)) {
  if (historyTask != null) {
    historyTask.cancel(true);
  }
  historyTask = new HistoryTask();
  historyTask.execute();
}else{
  setHistoryList(null);
}
}

private class HistoryTask extends AsyncTask<Void, Void, ArrayList<String>> {

@Override
protected ArrayList<String> doInBackground(Void... params) {
  String history = HelperUI.getSearchbarHistory(activity);
  if (!TextUtils.isEmpty(history)) {
    return new ArrayList<>(Arrays.asList(history.split("--")));
  }

  return new ArrayList<>(0);
}

@Override
protected void onPostExecute(ArrayList<String> results) {
  super.onPostExecute(results);
  if (!results.isEmpty()) {
    setHistoryList(results);
  }
  historyTask = null;
}
}

private class HistoryViewHolder extends RecyclerView.ViewHolder {
TextView hint, name;
ImageView img;

public HistoryViewHolder(View v) {
  super(v);
  name = (TextView) v.findViewById(R.id.app_label);
  hint = ((TextView) v.findViewById(R.id.type_label));
  img = ((ImageView) v.findViewById(R.id.item_icon));
}

public void bind(String suggestion) {
  name.setText(Html.fromHtml(suggestion));
  img.setImageDrawable(activity.getResources().getDrawable(R.drawable.ic_public_grey600_48dp));
  img.setTag(suggestion);
}
}
}

这是疯狂的部分，当我更新 setHistoryList 中的列表时，我知道回收器视图具有正确的适配器，但它不是 null … 但它有点失去它， Recycler 视图中不再有适配器，当它尝试通过 notifyDatasetChanged() 更新时……它就消失了，当然，什么也不显示。

知道出了什么问题吗？

原文由 Valentin Parsy 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

你必须添加一个布局管理器，就像你经常为 RecyclerView 创建的任何适配器一样。

  historyRecyclerView.setLayoutManager(new LinearLayoutManager(context));

只需在下面的代码下面添加这一行 setAdpater 您使用适配器设置回收器视图的位置。

原文由 Jai 发布，翻译遵循 CC BY-SA 4.0 许可协议