带有 TabLayout 和 Viewpager 的 SearchBar。 SearchBar (EditText) 不过滤用户，也不过滤事件

Question

我的 SearchFragment 是另外两个 Fragment 的宿主 Fragment：SearchUsersFragment 和 SearchEventsFragment。我组织它的方式是TabLayout 和Viewpager 在SearchFragment 中，RecyclerView、Adapters 和ArrayList 在两个子片段中。

我想做的是实现一个 SearchBar (EditText)，我已经在 SearchFragment 中完成了它并使用 SearchBar 过滤用户（在 @ 987654333@) 和事件 (SearchEventsFragment)。

问题：是我在每个子片段searchusers();和readUsers();中写了两个方法。我公开了方法searchUsers();，以便我可以将其添加到onTextChangedListener 的SearchFragment 中，但是名称以我在SearchBar 中键入的字母开头的用户仍然没有出现。

有人可以请告诉我如何解决这个问题吗？我已经为此工作了 3 天，但无法让用户或事件以某人在 SearchBar 中键入的字母开头。

搜索片段

public class SearchFragment extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.fragment_search, container, false);

        final TabLayout tabLayout = v.findViewById(R.id.tab_layout);
        final ViewPager viewPager = v.findViewById(R.id.viewpager);

        tabLayout.addTab(tabLayout.newTab().setIcon(R.drawable.icon_people_black));
        tabLayout.addTab(tabLayout.newTab().setIcon(R.drawable.icon_event_available_black));

        ViewPagerAdapter viewPagerAdapter = new ViewPagerAdapter(getChildFragmentManager());
        viewPagerAdapter.addFragment(new SearchUsersFragment(), "");
        viewPagerAdapter.addFragment(new SearchEventsFragment(), "");

        viewPager.setAdapter(viewPagerAdapter);
        viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
        tabLayout.addOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(viewPager));

        EditText searchBar = v.findViewById(R.id.search_bar);
        searchBar.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
                FragmentManager fragmentManager = getChildFragmentManager();
                SearchUsersFragment searchUsersFragment = (SearchUsersFragment) fragmentManager.findFragmentById(R.id.fragment_search_users);
                if (searchUsersFragment != null) {
                    searchUsersFragment.searchUsers(s.toString().toLowerCase());
                }
            }

            @Override
            public void afterTextChanged(Editable s) {

            }
        });

        return v;
    }

    static class ViewPagerAdapter extends FragmentPagerAdapter {

        private ArrayList<Fragment> mFragments;
        private ArrayList<String> mTitles;

        ViewPagerAdapter(@NonNull FragmentManager fm) {
            super(fm);
            this.mFragments = new ArrayList<>();
            this.mTitles = new ArrayList<>();
        }

        @NonNull
        @Override
        public Fragment getItem(int position) {
            return mFragments.get(position);
        }

        @Override
        public int getCount() {
            return mFragments.size();
        }

        void addFragment(Fragment fragment, String title) {
            mFragments.add(fragment);
            mTitles.add(title);
        }

        @Nullable
        @Override
        public CharSequence getPageTitle(int position) {
            return mTitles.get(position);
        }
    }
}

SearchUsersFragment

public class SearchUsersFragment extends Fragment {

    RecyclerView mRecyclerView;
    UserAdapter mUserAdapter;
    List<User> mUserList;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_search_users, container, false);

        mRecyclerView = view.findViewById(R.id.recycler_view);
        mRecyclerView.setHasFixedSize(true);
        mRecyclerView.setLayoutManager(new LinearLayoutManager(getContext()));

        mUserList = new ArrayList<>();
        mUserAdapter = new UserAdapter(getContext(), mUserList, true);
        mRecyclerView.setAdapter(mUserAdapter);

        readUsers();

        return view;
    }

    public void searchUsers(String s) {
        Query query = FirebaseDatabase.getInstance().getReference("Users").orderByChild("username").startAt(s).endAt(s + "\uf8ff");
        query.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                mUserList.clear();
                for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                    User user = snapshot.getValue(User.class);
                    if (user != null) {
                        mUserList.add(user);
                    }
                }

                mUserAdapter.notifyDataSetChanged();
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });
    }

    private void readUsers() {
        final FirebaseUser firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
        DatabaseReference reference = FirebaseDatabase.getInstance().getReference("Users");
        reference.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                mUserList.clear();
                for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                    User user = snapshot.getValue(User.class);
                    if (firebaseUser != null && user != null && !user.getId().equals(firebaseUser.getUid())) {
                        mUserList.add(user);
                    }
                }

                mUserAdapter.notifyDataSetChanged();
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });
    }
}

SearchEventsFragment

public class SearchEventsFragment extends Fragment {

    RecyclerView mRecyclerView;
    SearchEventsAdapter mSearchEventsAdapter;
    List<Post> mPostList;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_search_events, container, false);

        mRecyclerView = view.findViewById(R.id.recycler_view);
        mRecyclerView.setHasFixedSize(true);
        mRecyclerView.setLayoutManager(new LinearLayoutManager(getContext()));

        mPostList = new ArrayList<>();
        mSearchEventsAdapter = new SearchEventsAdapter(getContext(), mPostList);
        mRecyclerView.setAdapter(mSearchEventsAdapter);

        readEvents();

        return view;
    }

    private void readEvents() {
        DatabaseReference reference = FirebaseDatabase.getInstance().getReference("Posts");
        reference.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                mPostList.clear();
                for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                    Post post = snapshot.getValue(Post.class);
                    if (post != null) {
                        mPostList.add(post);
                    }
                }

                mSearchEventsAdapter.notifyDataSetChanged();
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });
    }
}

Answer 1

我在这里使用了一个 searchView 来过滤 3 个片段

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

        @Override
        public boolean onQueryTextChange(String newText) {

            mAdapter.getFilter().filter(newText);
            fAdapter.getFilter().filter(newText);
            rAdapter.getFilter().filter(newText);
            return false;
        }
    });

然后在我的适配器中，我完成了 implements Filterable 和

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

private Filter myFilter = new Filter() {
    @Override
    protected FilterResults performFiltering(CharSequence constraint) {

        ArrayList<String> filterList = new ArrayList<>();

        if (constraint == null || constraint.length() == 0) {
            filterList.addAll(MainActivity.Db.getWholeData());
        } else {
            String toFilter = constraint.toString().toLowerCase().trim();

            for (String item : MainActivity.Db.getWholeData()) {
                if (item.toLowerCase().contains(toFilter)) {
                    filterList.add(item);
                }
            }
        }

        clickPurposeFav = filterList;
        FilterResults filterResults = new FilterResults();
        filterResults.values = filterList;

        return filterResults;
    }

    @Override
    protected void publishResults(CharSequence constraint, FilterResults results) {          

        MainActivity.arrList.clear();
        MainActivity.arrList.addAll((List) results.values);

     }
};