在社交媒体Android应用程序中实现对主页上特定博客的搜索和注销功能

这是7的“建立一个社会化媒体应用Android Studio中”教程中的一部分，我们将要在本文中介绍了以下功能：

• 我们将在主页上搜索博客。
• 如果我们的应用程序中的博客很少，那么手动搜索博客就很容易。但是，当我们有1000个博客然后搜索特定博客时，发生的事情变得非常复杂且耗时。
• 因此，我们正在实现此功能，以便使用提供的标题或描述来搜索博客。
• 另外，我们在本文中实现了注销功能。

分步实施

步骤1：在菜单文件夹中创建注销和搜索按钮

转到应用程序> res>菜单>右键单击>新建>菜单资源文件，并将文件命名为main_menu 。以下是main_menu.xml文件的代码。

步骤2：使用HomeFragment。 Java文件

我们正在使用标题和描述值在节点“帖子”中搜索博客。如果有任何键值匹配，则所有值包含我们搜索内容的博客

if(modelPost.getTitle().toLowerCase().contains(search.toLowerCase())||
      modelPost.getDescription().toLowerCase().contains(search.toLowerCase())) {
      posts.add(modelPost);
  }

以下是注销功能的代码

@Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {

        if (item.getItemId() == R.id.logout) {
            firebaseAuth.signOut();
            startActivity(new Intent(getContext(), SpalshScreen.class));
            getActivity().finish();
        }

        return super.onOptionsItemSelected(item);
 }

转到HomeFragment。 Java文件并参考以下代码。以下是HomeFragment的完整和更新的代码。 Java文件。

Java

package com.example.socialmediaapp;
  
import android.content.Intent;
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 android.widget.Toast;
  
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.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 HomeFragment extends Fragment {
  
    FirebaseAuth firebaseAuth;
    String myuid;
    RecyclerView recyclerView;
    List posts;
    AdapterPosts adapterPosts;
  
    public HomeFragment() {
        // 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_home, container, false);
        firebaseAuth = FirebaseAuth.getInstance();
        recyclerView = view.findViewById(R.id.postrecyclerview);
        recyclerView.setHasFixedSize(true);
        LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
        layoutManager.setReverseLayout(true);
        layoutManager.setStackFromEnd(true);
        recyclerView.setLayoutManager(layoutManager);
        posts = new ArrayList<>();
        loadPosts();
        return view;
    }
  
    private void loadPosts() {
        DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference("Posts");
        databaseReference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                posts.clear();
                for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
                    ModelPost modelPost = dataSnapshot1.getValue(ModelPost.class);
                    posts.add(modelPost);
                    adapterPosts = new AdapterPosts(getActivity(), posts);
                    recyclerView.setAdapter(adapterPosts);
                }
            }
  
            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
                Toast.makeText(getActivity(), databaseError.getMessage(), Toast.LENGTH_LONG).show();
            }
        });
    }
  
    // Search post code
    private void searchPosts(final String search) {
        DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference("Posts");
        databaseReference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                posts.clear();
                for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
                    ModelPost modelPost = dataSnapshot1.getValue(ModelPost.class);
                    if (modelPost.getTitle().toLowerCase().contains(search.toLowerCase()) ||
                            modelPost.getDescription().toLowerCase().contains(search.toLowerCase())) {
                        posts.add(modelPost);
                    }
                    adapterPosts = new AdapterPosts(getActivity(), posts);
                    recyclerView.setAdapter(adapterPosts);
  
                }
            }
  
            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
                Toast.makeText(getActivity(), databaseError.getMessage(), Toast.LENGTH_LONG).show();
            }
        });
    }
  
    @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);
        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)) {
                    searchPosts(query);
                } else {
                    loadPosts();
                }
                return false;
            }
  
            @Override
            public boolean onQueryTextChange(String newText) {
                if (!TextUtils.isEmpty(newText)) {
                    searchPosts(newText);
                } else {
                    loadPosts();
                }
                return false;
            }
        });
  
        super.onCreateOptionsMenu(menu, inflater);
    }
  
    // Logout functionality
    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
  
        if (item.getItemId() == R.id.logout) {
            firebaseAuth.signOut();
            startActivity(new Intent(getContext(), SpalshScreen.class));
            getActivity().finish();
        }
  
        return super.onOptionsItemSelected(item);
    }
  
}

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：