AutoCompleteTextView不显示任何下拉菜单

Question

我正在处理自动完成文本视图用于获取匹配地方的需求。用户必须输入几个字符，并从服务器返回与这些字符匹配的Localities列表。自动完成文本视图然后应该显示这个列表作为下拉（或弹出）。出于某种原因，即使我从服务器接收到有效的地区信息，自动完成下拉菜单也不会出现。这是我的代码。

局部性（型号）

public class Locality { 
    private int Id; 
    private String name; 
    private boolean selected; 

    //Getters and Setters 
} 

DonorSearchFragment.xml（含有AutoCompleteTextView布局文件）

<AutoCompleteTextView 
    android:id="@+id/actLocality" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" /> 

LocalityListAdapter视图（locality_row.xml）

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    ... 
    <TextView 
     android:id="@+id/txvLocalityName" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     /> 

</LinearLayout> 

LocalityListAdapter.java

public class LocalityListAdapter extends ArrayAdapter<Locality> { 

    List<Locality> localities; 
    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     //The Current View 
     View view = convertView; 
     if (view == null) { 
      LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
      view = inflater.inflate(R.layout.locality_row, null); 
     } 
     Locality currentLocality = localities.get(position); 
     if (currentLocality != null) { 
      TextView txvLocalityName = (TextView) view.findViewById(R.id.txvLocalityName); 
      txvLocalityName.setText(currentLocality.getName()); 
     } 
     return view; 
    } 
} 

DonorSearchFragment.java（片段表示AutoCompleteTextView）

在onPostExecute（）我检查，我接收有效地点列表，然后将它们推入支持适配器的LocalityList中，但这些地区不会通过下拉列表显示。实际上没有显示下拉菜单。任何可能导致错误或遗漏的原因？

Answer 1

我觉得有一个更好的方法来处理这种情况，避免使用AsyncTask。可以使用Filter，它提供了performFiltering()实际在工作线程中运行的回调。这里匹配的数据可以被决定/准备（如通过服务器调用或类似的）。在准备结果时，可以使用在UI线程上运行的publishResults回调来修改支持自定义适配器的列表。我刚刚开始了解Android适配器，所以我可能在这里不正确。下面是我使用

public class LocalityListAdapter extends ArrayAdapter<Locality> { 

    List<Locality> localities; 
    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     View view = convertView; 
     if (view == null) { 
      LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
      view = inflater.inflate(R.layout.locality_row, null); 
     } 
     Locality currentLocality = localities.get(position); 
     if (currentLocality != null) { 
      TextView txvLocalityName = (TextView) view.findViewById(R.id.txvLocalityName); 
      txvLocalityName.setText(currentLocality.getName()); 
     } 
     return view; 
    } 

    @Override 
    public Filter getFilter() { 
     return localityFilter; 
    } 

    Filter localityFilter = new Filter() { 
     @Override 
     public CharSequence convertResultToString(Object resultValue) { 
      Locality locality = (Locality) resultValue; 
      return locality.getName(); 
     } 

     protected FilterResults performFiltering(CharSequence constraint) { 
      List<Locality> localityList = new ArrayList<Locality>(); 
      ...Get Data from Server 
      //Return FilterResults created from response 
      FilterResults filterResults = new FilterResults(); 
      filterResults.values = localityList; 
      filterResults.count = localityList.size(); 
      return filterResults; 
     } 

     @Override 
     protected void publishResults(CharSequence charSequence, FilterResults filterResults) { 
      localities.clear(); 
      List<Locality> filteredList = (List<Locality>) filterResults.values; 
      for(Locality locality : filteredList) { 
       localities.add(locality); 
      } 
      notifyDataSetChanged(); 
     } 
    } 
}    

DonorSearchFragment.java（从MainActivity）

public class DonorSearchFragment extends Fragment { 
    ... 
    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
          Bundle savedInstanceState) { 
     searchFragmentView = inflater.inflate(R.layout.fragment_donor_search, container, false); 

     //Locality AutoComplete 
     localityList = new ArrayList<Locality>(); 
     actLocality = (AutoCompleteTextView) searchFragmentView.findViewById(R.id.actLocality); 
     localityListAdapter = new LocalityListAdapter(this.getActivity(), R.layout.locality_row, localityList); 
     actLocality.setAdapter(localityListAdapter); 
     ... 
     return searchFragmentView; 
    } 
} 

代码