SearchView for RecyclerView 不起作用

Question

我已经在片段中为回收器视图实现了搜索视图过滤器，如下所示，但是当我在搜索视图中输入查询时，没有任何反应。

我的片段类：讨论论坛.java

public class DiscussionForum extends Fragment implements ForumAdapter.ForumAdapterListener {

private TextView socname;
private EditText messageinput;
private SearchView search;
// SearchView searchView;
private FloatingActionButton messagesend;
ProgressDialog progressDialog;
private static final String TAG = "Discussion Forum";
private RecyclerView recyclerView;
private List<ForumData> forumlist;
private ForumAdapter mAdapter;
private OnFragmentInteractionListener mListener;
private LinearLayout list;
private String sendurl, geturl;
public DiscussionForum() {
// Required empty public constructor
}

public static DiscussionForum newInstance(String param1, String param2) {
DiscussionForum fragment = new DiscussionForum();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
@Override
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {      
View view = inflater.inflate(R.layout.fragment_discussion_forum, container, false);
onButtonPressed("Discussion Forum");      
forumlist = new ArrayList<>();
recyclerView = view.findViewById(R.id.listviewforum);
list = view.findViewById(R.id.list);
search = view.findViewById(R.id.search);
int resId = R.anim.layout_animation_fall_down;
LayoutAnimationController animation = AnimationUtils.loadLayoutAnimation(getContext(), resId);
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getContext());
recyclerView.setLayoutManager(mLayoutManager);
recyclerView.setLayoutAnimation(animation);
mAdapter = new ForumAdapter(getContext(), forumlist, this);
progressDialog = new ProgressDialog(getContext());
progressDialog.setCancelable(false);        
geturl = "";         
fetchforumdata(getActivity().getIntent().getStringExtra("id"));
search.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
@Override
public boolean onQueryTextSubmit(String query) {
return false;
}
@Override
public boolean onQueryTextChange(String newText) {
mAdapter.getFilter().filter(newText);
return true;
}
});
return view;
}

private void fetchforumdata(final String id1) {
progressDialog.setMessage("Loading...");
showDialog();
StringRequest request = new StringRequest(Request.Method.GET,
geturl + id1,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
// Log.d("tag2","id"+id1);
Log.d(TAG, "Response Prop: " + response.toString());
hideDialog();
try {
JSONObject jObj = new JSONObject(response);
boolean error = jObj.getBoolean("errors");
if (!error) {
JSONObject dataobj = jObj.getJSONObject("data");
JSONArray ticketarray = dataobj.getJSONArray("result");
if (ticketarray.length() == 0) {
list.setVisibility(View.VISIBLE);
} else {
recyclerView.setVisibility(View.VISIBLE);
List<ForumData> items = new Gson().fromJson(ticketarray.toString(), new TypeToken<List<ForumData>>() {
}.getType());
forumlist.clear();
forumlist.addAll(items);
recyclerView.setAdapter(mAdapter);
}
} else {
// String errorMsg = jObj.getString("error_msg");
Toast.makeText(getContext(),
"Try again or report an issue", Toast.LENGTH_LONG).show();
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
// error in getting json
Log.e(TAG, "Error: " + error.getMessage());
Toast.makeText(getContext(), "Error: " + error.getMessage(), Toast.LENGTH_SHORT).show();
hideDialog();
}
});
MyApplication.getInstance().addToRequestQueue(request);
}

// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(String title) {
if (mListener != null) {
mListener.onFragmentInteraction(title);
}
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
private void showDialog() {
if (!progressDialog.isShowing())
progressDialog.show();
}
private void hideDialog() {
if (progressDialog.isShowing())
progressDialog.dismiss();
}
@Override
public void onDocumentSelected(String id) {
}
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(String title);
}}

我的适配器类：论坛适配器

public class ForumAdapter extends RecyclerView.Adapter<ForumAdapter.MyViewHolder> implements Filterable {
private Context context;
private List<ForumData> ticketlist;
private List<ForumData> filterlist;
private ForumAdapterListener listener;


public class MyViewHolder extends RecyclerView.ViewHolder {
TextView username,createdat,forummessage,flatno,category,likes,subcount;
ImageView edit;
public MyViewHolder(View view) {
super(view);
username=view.findViewById(R.id.user_name2);
createdat=view.findViewById(R.id.date2);
edit = view.findViewById(R.id.profile_icon2);
forummessage=view.findViewById(R.id.forum_message);
flatno=view.findViewById(R.id.flat_no);
category=view.findViewById(R.id.category);
likes=view.findViewById(R.id.likes_data);
subcount=view.findViewById(R.id.count_data);
}
}
public ForumAdapter(Context context, List<ForumData> ticketlist, ForumAdapterListener listener) {
this.context = context;
this.listener = listener;
this.ticketlist = ticketlist;
this.filterlist=ticketlist;
}
@Override
public ForumAdapter.MyViewHolder onCreateViewHolder( ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.discussion_forum_item, parent, false);
return new MyViewHolder(itemView);
}
@Override
public void onBindViewHolder( ForumAdapter.MyViewHolder holder, int position) {
final ForumData contact = ticketlist.get(position);
holder.username.setText(contact.getUsername());
holder.flatno.setText(contact.getFlattitle());
holder.forummessage.setText(contact.getMessage());
holder.createdat.setText(contact.getCreated_at());
holder.category.setText(contact.getCategory());      
holder.likes.setText(contact.getLikes());       
holder.subcount.setText(contact.getSubcount());
Glide.with(context)
.load(url+".jpg")
.apply(new RequestOptions().circleCrop().placeholder(R.drawable.man).error(R.drawable.man))
.into(holder.edit);
}
});
}
@Override
public int getItemCount() {
return ticketlist.size();
}

@Override
public Filter getFilter() {
return new Filter() {
@Override
protected FilterResults performFiltering(CharSequence charSequence) {
String charString = charSequence.toString();
if (charString.isEmpty()) {
filterlist = ticketlist;
} else {
List<ForumData> filteredList = new ArrayList<>();
for (ForumData row : ticketlist) {
// name match condition. this might differ depending on your requirement
// here we are looking for name or phone number match
if (row.getUsername().toLowerCase().contains(charString.toLowerCase()) || row.getCategory().contains(charSequence)) {
filteredList.add(row);
}
}
filterlist = filteredList;
}
FilterResults filterResults = new FilterResults();
filterResults.values = filterlist;
return filterResults;
}
@Override
protected void publishResults(CharSequence constraint, FilterResults results) {
filterlist = (ArrayList<ForumData>) results.values;
notifyDataSetChanged();
}
}
;
}
public interface ForumAdapterListener {
void onDocumentSelected(String contact);
}}

我已经经历了许多解决方案，例如这里，这里，这里但是
我无法弄清楚我的代码出了什么问题。请帮我找出确切的问题所在。

Answer 1

适配器实现存在多个问题。如果我正确理解您的代码，您希望保留对未过滤项目列表(List<ForumData> ticketlist(的引用，并过滤此列表并在屏幕上显示过滤结果(List<ForumData> filterlist(。

首先，您希望在屏幕上显示filterlist，因此在onBindViewHolder()和getItemCount()中，您需要使用filterlist而不是ticketlist.

其次，您要确保ticketlist保持不变，以便所有将来的搜索都位于相同的内容上。为此，您必须将所有filterlist = ticketlist;替换为filterlist = new ArrayList<>(ticketlist);(在您的结构体和performFiltering()中(，以避免更改ticketlist的内容。

这应该至少使您的代码正常运行。我建议你也观看这个关于Java以及对象和引用的视频。

Answer 2

另一种方法是过滤数据并在onQueryTextChange中刷新回收器视图的适配器：

searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
@Override
public boolean onQueryTextSubmit(String query) {

}
@Override
public boolean onQueryTextChange(String newText) {
ArrayList< ForumData > filteredData = new ArrayList<>();
for (ForumData forumData : data) {
if (forumData..getUsername().toLowerCase().contains(newText.toLowerCase())) {
filteredData.add(forumData);
}
}
adapter = new ForumAdapter(data, getContext() , this);
recyclerView.setAdapter(adapter);
return true ;
}
})