如何在 ViewPager 內的片段中過濾 RecyclerView

Question

我想使用 SearchView 來過濾我的 RecylerView，（RecyclerView），它位於一個片段中，它位於 ViewPager 中，ViewPager 位於自定義布局中，並且此自定義布局包含在主活動布局中。

我已經在 RecyclerView 適配器中實現了過濾邏輯。

我想知道在哪里調用過濾器方法，以及如何獲取對 RecyclerView 的引用。

這是 RecyclerView 的適配器類：

public class cardAdapter extends RecyclerView.Adapter<cardAdapter.noteHolder> implements Filterable {

private List<singleNoteDetail> myNotesList;
private List<singleNoteDetail> myNotesListFull;
private OnItemClickListenerMyNotes listener;



public static class noteHolder extends RecyclerView.ViewHolder {
    protected static TextView titleField;
    protected static TextView dateField;

    public noteHolder(View v) {
        super(v);
        titleField = v.findViewById(R.id.singleNoteTitle);
        dateField = v.findViewById(R.id.singleNoteDate);
    }
    public void bind(final singleNoteDetail item, final OnItemClickListenerMyNotes listener) {
        itemView.setOnClickListener(new View.OnClickListener() {
            @Override public void onClick(View v) {
                listener.onItemClick(item);
            }
        });
    }
}
public cardAdapter(List<singleNoteDetail> myNotesList,OnItemClickListenerMyNotes listener) {
    this.myNotesList = myNotesList;
    this.myNotesListFull = new ArrayList<>(myNotesList);
    this.listener = listener;
}

@NonNull
@Override
public noteHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
    View itemView = LayoutInflater.from(viewGroup.getContext())
            .inflate(R.layout.single_note_card, viewGroup, false);
    return new noteHolder(itemView);
}

@Override
public void onBindViewHolder(@NonNull noteHolder viewHolder, int i) {
    singleNoteDetail singleNoteDetail = myNotesList.get(i);
    noteHolder.titleField.setText(singleNoteDetail.title);
    noteHolder.dateField.setText(singleNoteDetail.date);
    viewHolder.bind(myNotesList.get(i), listener);
}


@Override
public int getItemCount() {
    return myNotesList.size();
}

@Override
public long getItemId(int position) {
    return position;
}

@Override
public int getItemViewType(int position) {
    return position;
}

@Override
public Filter getFilter() {
    return filter;

}

private Filter filter = new Filter() {
    @Override
    protected FilterResults performFiltering(CharSequence constraint) {
        List<singleNoteDetail> filteredList = new ArrayList<>();
        if(constraint == null || constraint.length() == 0){
            filteredList.addAll(myNotesListFull);
        }else{
            String pattern = constraint.toString().toLowerCase().trim();
            for(singleNoteDetail item : myNotesListFull){
                if(item.getTitle().toLowerCase().contains(pattern)){
                    filteredList.add(item);
                }
            }
        }
        FilterResults results = new FilterResults();
        results.values = filteredList;
        return results;
    }

    @Override
    protected void publishResults(CharSequence constraint, FilterResults results) {
        myNotesList.clear();
        myNotesList.addAll((List)results.values);
        notifyDataSetChanged();
    }
};


}

這是片段類：

public class MyNotes extends Fragment {

SharedPreferences prefs;

RecyclerView recyclerView;

SearchView searchView;

public RecyclerView.LayoutManager layoutManager;
public List<singleNoteDetail> cardList;
public RecyclerView.Adapter adapter;
ProgressBar progressBar;


// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";

// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;

private OnFragmentInteractionListener mListener;

public MyNotes() {
    // Required empty public constructor
}

public void syncMyNotes(){

    //

}
public static MyNotes newInstance(String param1, String param2) {
    MyNotes fragment = new MyNotes();
    Bundle args = new Bundle();
    args.putString(ARG_PARAM1, param1);
    args.putString(ARG_PARAM2, param2);
    fragment.setArguments(args);
    return fragment;
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (getArguments() != null) {
        mParam1 = getArguments().getString(ARG_PARAM1);
        mParam2 = getArguments().getString(ARG_PARAM2);


    }
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    prefs = getActivity().getSharedPreferences("Username",Context.MODE_PRIVATE);

    View view = inflater.inflate(R.layout.fragment_my_notes, container, false);

    recyclerView = view.findViewById(R.id.myNotesList);

    progressBar = view.findViewById(R.id.progress);



    layoutManager = new LinearLayoutManager( getActivity());
    recyclerView.setLayoutManager(layoutManager);
    recyclerView.setItemAnimator(new DefaultItemAnimator());


    syncMyNotes();


    adapter = new cardAdapter(cardList, new OnItemClickListenerMyNotes() {
        @Override
        public void onItemClick(singleNoteDetail item) {
            Intent i = new Intent(getActivity(),NoteEditingActivity.class);
            i.putExtra("noteTitle",item.title);
            startActivity(i);
        }
    });
    recyclerView.setAdapter(adapter);
    return view;
}

public void onButtonPressed(Uri uri) {
    if (mListener != null) {
        mListener.onFragmentInteraction(uri);
    }
}

@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 onAttachFragment(Fragment fragment) {
    // TODO Auto-generated method stub
    super.onAttachFragment(fragment);

    Toast.makeText(getActivity().getApplicationContext(), String.valueOf(fragment.getId()), Toast.LENGTH_SHORT).show();

}

@Override
public void onDetach() {
    super.onDetach();
    mListener = null;
}
public interface OnFragmentInteractionListener {
    // TODO: Update argument type and name
    void onFragmentInteraction(Uri uri);
}
}

這是包含 SearchView 和 ViewPager 的布局

existing_notes_layout.xml ：

<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/customborder"
android:orientation="vertical"
android:gravity="center_horizontal">

<android.support.design.widget.TabLayout
    android:id="@+id/tablayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/colorPrimary"
    android:minHeight="?attr/actionBarSize"
    android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

</android.support.design.widget.TabLayout>

<SearchView
    android:id="@+id/searchNotes"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    >

</SearchView>

<android.support.v4.view.ViewPager
    android:id="@+id/pager"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

</android.support.v4.view.ViewPager>

Answer 1

好吧，我遇到了完全類似的問題。 我所做的是：首先給你的customlayout id，即existing_notes_layout。 然后在 onCreateView 中的片段中編寫以下代碼：

   View view1 = getActivity().findViewById(R.id.activity); where "activity" is the id given to the customlayout i.e. existing_notes_layout.Then, find the id for the searchview you defined in your customlayout. like,

    SearchView searchview = view1.findViewById(R.id.searchNotes);

然后，最后你可以實現searchview的以下方法。

     searchview.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
        @Override
        public boolean onQueryTextSubmit(String query) {
            return false;
        }

        @Override
        public boolean onQueryTextChange(String newText) {
            cardAdapter.getFilter().filter(newText);
            return false;
        }
    });

Answer 2

因為您已經在片段中包含了搜索視圖。 然后你可以在查詢文本更改時獲取過濾器並提交。 這樣做的示例方法如下：

public class MyNotes extends Fragment implements SearchView.OnQueryTextListener {

.........
..........
........

        @Override
        public boolean onQueryTextSubmit(String query) {

            return false;
        }

        @Override
        public boolean onQueryTextChange(String newText) {

// If you have not instantiated your adapter then you must instantiate it

   CardAdapter adapter = new cardAdapter(cardList, new OnItemClickListenerMyNotes() {
    @Override
    public void onItemClick(singleNoteDetail item) {
        Intent i = new Intent(getActivity(),NoteEditingActivity.class);
        i.putExtra("noteTitle",item.title);
        startActivity(i);
    }
});

// If you have already instantiated it you can start with this

            if (adapter != null && newText != null) {
                adapter.getFilter().filter(newText);

                return true;
            }

            return false;


        }


}

Answer 3

以后誰來這里，這里就是這種場景的解決方案。

更好的方法是使用 EventBus。 在我們必須將某些數據從 Activity 傳遞到 Fragment 的場景中，這真的很有幫助。

為了使用EventBus，添加這個庫實現'org.greenrobot:eventbus:3.0.0'，然后你需要定義一個POJO類，有點像這樣：

class SearchQueryEvent {
String query;

public SearchQueryEvent(String query) {
    this.query=query;
}

public String getQuery() {
    return query;
}

}

現在，您的代碼應該像這樣修改：

主活動.java

SearchView searchView;
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate( R.menu.main, menu);

MenuItem myActionMenuItem = menu.findItem( R.id.action_search);
searchView = (SearchView) myActionMenuItem.getActionView();
searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
    @Override
    public boolean onQueryTextSubmit(String query) {
        return false;
    }
    @Override
    public boolean onQueryTextChange(String s) {
        EventBus.getDefault().post(new SearchQueryEvent(s));
        return false;
    }
});
return true;

}

你的片段.java

    @Override
public void onResume() {
    super.onResume();
    EventBus.getDefault().register(this);
}

@Override
public void onPause() {
    EventBus.getDefault().unregister(this);
    super.onPause();
}

@Subscribe(threadMode = ThreadMode.MAIN)
public void onSearchQuery(SearchQueryEvent event) {
    String query=event.getQuery();
    adapter.getFilter().filter(query);
}