如何在Social Media Android App中实现搜索注册用户功能？

这是9的“建立一个社交媒体应用程序在Android工作室”教程中的一部分，我们将要在本文中介绍了以下功能：

• 我们将在“用户”页面上搜索用户。
• 如果在我们的应用程序中注册的人很少，那么搜索一个人就很容易。
• 但是，当我们有1000个用户在我们的应用程序中注册然后搜索特定用户时，发生的事情变得非常复杂且耗时。
• 这就是我们实施此功能以使用提供的名称或电子邮件搜索用户的原因。

分步实施

步骤1：使用main_menu.xml文件

在main_menu.xml文件中添加“搜索”图标。

步骤2：使用UsersFragment。 Java文件

在此文件中添加searchusers() 。

Java

private void searchusers(final String s) {
        final FirebaseUser firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
        DatabaseReference reference = FirebaseDatabase.getInstance().getReference("Users");
        reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                usersList.clear();
                for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
                    ModelUsers modelUsers = dataSnapshot1.getValue(ModelUsers.class);
                    if (!modelUsers.getUid().equals(firebaseUser.getUid())) {
                        if (modelUsers.getName().toLowerCase().contains(s.toLowerCase()) ||
                                modelUsers.getEmail().toLowerCase().contains(s.toLowerCase())) {
                            usersList.add(modelUsers);
                        }
                    }
                    adapterUsers = new AdapterUsers(getActivity(), usersList);
                    adapterUsers.notifyDataSetChanged();
                    recyclerView.setAdapter(adapterUsers);
                }
  
            }
  
            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
  
            }
    });
}

以下是UsersFragment的更新代码。 Java文件。

Java

package com.example.socialmediaapp;
  
import android.os.Bundle;
import android.text.TextUtils;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.SearchView;
  
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.core.view.MenuItemCompat;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
  
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
  
import java.util.ArrayList;
import java.util.List;
  
/**
 * A simple {@link Fragment} subclass.
 */
public class UsersFragment extends Fragment {
  
    RecyclerView recyclerView;
    AdapterUsers adapterUsers;
    List usersList;
    FirebaseAuth firebaseAuth;
  
    public UsersFragment() {
        // Required empty public constructor
    }
  
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment_users, container, false);
        recyclerView = view.findViewById(R.id.recyclep);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
        usersList = new ArrayList<>();
        firebaseAuth = FirebaseAuth.getInstance();
        getAllUsers();
        return view;
    }
  
    private void getAllUsers() {
        final FirebaseUser firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
        DatabaseReference reference = FirebaseDatabase.getInstance().getReference("Users");
        reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                usersList.clear();
                for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
                    ModelUsers modelUsers = dataSnapshot1.getValue(ModelUsers.class);
                    if (modelUsers.getUid() != null && !modelUsers.getUid().equals(firebaseUser.getUid())) {
                        usersList.add(modelUsers);
                    }
                    adapterUsers = new AdapterUsers(getActivity(), usersList);
                    recyclerView.setAdapter(adapterUsers);
                }
  
            }
  
            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
  
            }
        });
    }
  
    private void searchusers(final String s) {
        final FirebaseUser firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
        DatabaseReference reference = FirebaseDatabase.getInstance().getReference("Users");
        reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                usersList.clear();
                for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
                    ModelUsers modelUsers = dataSnapshot1.getValue(ModelUsers.class);
                    if (modelUsers.getUid() != null && !modelUsers.getUid().equals(firebaseUser.getUid())) {
                        if (modelUsers.getName().toLowerCase().contains(s.toLowerCase()) ||
                                modelUsers.getEmail().toLowerCase().contains(s.toLowerCase())) {
                            usersList.add(modelUsers);
                        }
                    }
                    adapterUsers = new AdapterUsers(getActivity(), usersList);
                    adapterUsers.notifyDataSetChanged();
                    recyclerView.setAdapter(adapterUsers);
                }
  
            }
  
            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
  
            }
        });
    }
  
    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        setHasOptionsMenu(true);
        super.onCreate(savedInstanceState);
    }
  
    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        inflater.inflate(R.menu.main_menu, menu);
        menu.findItem(R.id.logout).setVisible(false);
        MenuItem item = menu.findItem(R.id.search);
        SearchView searchView = (SearchView) MenuItemCompat.getActionView(item);
        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String query) {
                if (!TextUtils.isEmpty(query.trim())) {
                    searchusers(query);
                } else {
                    getAllUsers();
                }
                return false;
            }
  
            @Override
            public boolean onQueryTextChange(String newText) {
                if (!TextUtils.isEmpty(newText.trim())) {
                    searchusers(newText);
                } else {
                    getAllUsers();
                }
                return false;
            }
        });
  
        super.onCreateOptionsMenu(menu, inflater);
    }
      
}

输出：

对于本文中使用的所有可绘制文件，请参考以下链接： https://drive.google.com/drive/folders/1M_knOH_ugCuwSP5nkYzeD4dRp-Honzbe?usp=sharing

下面是执行这些操作后的文件结构：