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只包含适配器列表。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);
}
}
}

这是一个疯狂的部分，当我更新setHistoryList中的列表时，我知道回收器视图有正确的适配器，它不是null ...但是它有点失去它，没有当它试图按notifyDatasetChanged()进行更新时，在Recycler视图中有更多适配器...它只是消失了，并且没有显示任何内容。

知道什么是错的吗？

Answer 1

您必须像定期使用为RecyclerView创建的任何适配器一样添加布局管理器。

 historyRecyclerView.setLayoutManager(new LinearLayoutManager(context));

只需在setAdpater下方的代码下方添加此行，您可以使用adpapter设置回收站视图。

Answer 2

您也可以将此添加到xml（感谢@Indra Kumar S）

app:layoutManager="android.support.v7.widget.LinearLayoutManager"

Answer 3

我的私人变量在这里

private RecyclerView recycleViewtask;
private RecyclerView.LayoutManager mLayoutManager;

然后我分配以下内容

    recycleViewtask = findViewById(R.id.recycleViewtask);

    recycleViewtask.setHasFixedSize(true);
    // use a linear layout manager
    mLayoutManager = new LinearLayoutManager(this);
    recycleViewtask.setLayoutManager(mLayoutManager);

Answer 4

对于使用AndroidX的用户，对@Doongsil的解决方案稍作修改：

app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"

不可能：没有附加布局经理;跳过布局

4 个答案: