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How to Retrieve Blog On Home Page in Social Media Android App?
  • Last Updated : 09 Apr, 2021

This is the Part 6 of “Build a Social Media App in Android Studio” tutorial, and we are going to cover the following functionalities in this article:

  • We are going to retrieve the blogs written by users on HomeFragment.
  • Here we have only shown the user data and title, description, and image of the blogs, but we are also going to implement the like and comment feature in upcoming blogs.
  • Then We will be showing Post details Activity where users will be able to comment.
  • We have also implemented the Like a Blog functionality.

Step By Step Implementation

Step 1: Create a new layout resource file

Go to the app > res > layout > New > Layout Resource File and name the file as row_posts. Below is the code for the row_posts.xml file.

XML




<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView 
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    app:cardBackgroundColor="@color/colorWhite"
    app:cardCornerRadius="3dp"
    app:cardElevation="3dp"
    app:cardUseCompatPadding="true"
    app:contentPadding="5dp">
  
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">
  
        <LinearLayout
            android:id="@+id/profilelayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center_vertical"
            android:orientation="horizontal">
  
            <de.hdodenhof.circleimageview.CircleImageView
                android:id="@+id/picturetv"
                android:layout_width="50dp"
                android:layout_height="50dp"
                android:scaleType="centerCrop"
                android:src="@drawable/profile_image" />
  
            <LinearLayout
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:orientation="vertical">
  
                <TextView
                    android:id="@+id/unametv"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="Name"
                    android:textColor="@color/colorBlack"
                    android:textSize="20sp" />
  
                <TextView
                    android:id="@+id/utimetv"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="33 min" />
  
            </LinearLayout>
  
            <ImageButton
                android:id="@+id/morebtn"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:background="@null"
                android:src="@drawable/ic_more" />
  
        </LinearLayout>
  
        <TextView
            android:id="@+id/ptitletv"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Title"
            android:textSize="16sp"
            android:textStyle="bold" />
  
        <TextView
            android:id="@+id/descript"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Description"
            android:textColor="@color/colorBlack" />
  
        <ImageView
            android:id="@+id/pimagetv"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@color/colorWhite" />
  
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">
  
            <TextView
                android:id="@+id/plikeb"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="1.2K Likes"
                android:textColor="@color/colorPrimary" />
  
            <TextView
                android:id="@+id/pcommentco"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="1.2K Comment"
                android:textAlignment="textEnd"
                android:textColor="@color/colorPrimary" />
        </LinearLayout>
  
        <View
            android:layout_width="match_parent"
            android:layout_height="1dp"
            android:background="#F5F0F0" />
  
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:orientation="horizontal">
  
            <Button
                android:id="@+id/like"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:autoLink="all"
                android:background="@color/colorWhite"
                android:drawableStart="@drawable/ic_like"
                android:drawableLeft="@drawable/ic_like"
                android:padding="5dp"
                android:text="Like" />
  
            <Button
                android:id="@+id/comment"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:autoLink="all"
  
                android:background="@color/colorWhite"
                android:drawableStart="@drawable/ic_comment"
                android:drawableLeft="@drawable/ic_comment"
                android:padding="5dp"
                android:text="COMMENT" />
        </LinearLayout>
  
    </LinearLayout>
  
</androidx.cardview.widget.CardView>

Step 2: Create a new java class



Refer to this article Create Classes in Android Studio and name the class as ModelPost. Below is the code for the ModelPost.java file. Created this class to initialize the key so that we can retrieve the value of the key later. 

Java




package com.example.socialmediaapp;
  
public class ModelPost {
    public ModelPost() {
    }
  
    String description;
  
    public String getDescription() {
        return description;
    }
  
    public void setDescription(String description) {
        this.description = description;
    }
  
    public String getPid() {
        return pid;
    }
  
    public void setPid(String pid) {
        this.pid = pid;
    }
  
    public String getPtime() {
        return ptime;
    }
  
    public void setPtime(String ptime) {
        this.ptime = ptime;
    }
  
    public String getTitle() {
        return title;
    }
  
    public void setTitle(String title) {
        this.title = title;
    }
  
    public String getUdp() {
        return udp;
    }
  
    public void setUdp(String udp) {
        this.udp = udp;
    }
  
    public String getUemail() {
        return uemail;
    }
  
    public void setUemail(String uemail) {
        this.uemail = uemail;
    }
  
    public String getUid() {
        return uid;
    }
  
    public void setUid(String uid) {
        this.uid = uid;
    }
  
    public String getUimage() {
        return uimage;
    }
  
    public void setUimage(String uimage) {
        this.uimage = uimage;
    }
  
    public String getUname() {
        return uname;
    }
  
    public void setUname(String uname) {
        this.uname = uname;
    }
  
    public String getPlike() {
        return plike;
    }
  
    public void setPlike(String plike) {
        this.plike = plike;
    }
  
    String pid;
  
    public String getPcomments() {
        return pcomments;
    }
  
    public void setPcomments(String pcomments) {
        this.pcomments = pcomments;
    }
  
    public ModelPost(String description, String pid, String ptime, String pcomments, String title, String udp, String uemail, String uid, String uimage, String uname, String plike) {
        this.description = description;
        this.pid = pid;
        this.ptime = ptime;
        this.pcomments = pcomments;
        this.title = title;
        this.udp = udp;
        this.uemail = uemail;
        this.uid = uid;
        this.uimage = uimage;
        this.uname = uname;
        this.plike = plike;
    }
  
    String ptime, pcomments;
      
    String title;
  
    String udp;
    String uemail;
    String uid;
    String uimage;
  
    String uname, plike;
      
}

Similarly, create another java class and name the class as AdapterPosts. Below is the code for the AdapterPosts.java file. 

Java




package com.example.socialmediaapp;
  
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.text.format.DateFormat;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.PopupMenu;
import android.widget.TextView;
import android.widget.Toast;
  
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
  
import com.bumptech.glide.Glide;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
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.Query;
import com.google.firebase.database.ValueEventListener;
import com.google.firebase.storage.FirebaseStorage;
import com.google.firebase.storage.StorageReference;
  
import java.util.Calendar;
import java.util.List;
import java.util.Locale;
  
public class AdapterPosts extends RecyclerView.Adapter<com.example.socialmediaapp.AdapterPosts.MyHolder> {
      
    Context context;
    String myuid;
    private DatabaseReference liekeref, postref;
    boolean mprocesslike = false;
  
    public AdapterPosts(Context context, List<ModelPost> modelPosts) {
        this.context = context;
        this.modelPosts = modelPosts;
        myuid = FirebaseAuth.getInstance().getCurrentUser().getUid();
        liekeref = FirebaseDatabase.getInstance().getReference().child("Likes");
        postref = FirebaseDatabase.getInstance().getReference().child("Posts");
    }
  
    List<ModelPost> modelPosts;
  
    @NonNull
    @Override
    public MyHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(context).inflate(R.layout.row_posts, parent, false);
        return new MyHolder(view);
    }
  
    @Override
    public void onBindViewHolder(@NonNull final MyHolder holder, final int position) {
        final String uid = modelPosts.get(position).getUid();
        String nameh = modelPosts.get(position).getUname();
        final String titlee = modelPosts.get(position).getTitle();
        final String descri = modelPosts.get(position).getDescription();
        final String ptime = modelPosts.get(position).getPtime();
        String dp = modelPosts.get(position).getUdp();
        String plike = modelPosts.get(position).getPlike();
        final String image = modelPosts.get(position).getUimage();
        String email = modelPosts.get(position).getUemail();
        String comm = modelPosts.get(position).getPcomments();
        final String pid = modelPosts.get(position).getPtime();
        Calendar calendar = Calendar.getInstance(Locale.ENGLISH);
        calendar.setTimeInMillis(Long.parseLong(ptime));
        String timedate = DateFormat.format("dd/MM/yyyy hh:mm aa", calendar).toString();
        holder.name.setText(nameh);
        holder.title.setText(titlee);
        holder.description.setText(descri);
        holder.time.setText(timedate);
        holder.like.setText(plike + " Likes");
        holder.comments.setText(comm + " Comments");
        setLikes(holder, ptime);
        try {
            Glide.with(context).load(dp).into(holder.picture);
        } catch (Exception e) {
  
        }
        holder.image.setVisibility(View.VISIBLE);
        try {
            Glide.with(context).load(image).into(holder.image);
        } catch (Exception e) {
  
        }
        holder.like.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(holder.itemView.getContext(), PostLikedByActivity.class);
                intent.putExtra("pid", pid);
                holder.itemView.getContext().startActivity(intent);
            }
        });
        holder.likebtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                final int plike = Integer.parseInt(modelPosts.get(position).getPlike());
                mprocesslike = true;
                final String postid = modelPosts.get(position).getPtime();
                liekeref.addValueEventListener(new ValueEventListener() {
                    @Override
                    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                        if (mprocesslike) {
                            if (dataSnapshot.child(postid).hasChild(myuid)) {
                                postref.child(postid).child("plike").setValue("" + (plike - 1));
                                liekeref.child(postid).child(myuid).removeValue();
                                mprocesslike = false;
                            } else {
                                postref.child(postid).child("plike").setValue("" + (plike + 1));
                                liekeref.child(postid).child(myuid).setValue("Liked");
                                mprocesslike = false;
                            }
                        }
                    }
  
                    @Override
                    public void onCancelled(@NonNull DatabaseError databaseError) {
  
                    }
                });
            }
        });
        holder.more.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                showMoreOptions(holder.more, uid, myuid, ptime, image);
            }
        });
        holder.comment.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(context, PostDetailsActivity.class);
                intent.putExtra("pid", ptime);
                context.startActivity(intent);
            }
        });
    }
  
    private void showMoreOptions(ImageButton more, String uid, String myuid, final String pid, final String image) {
        PopupMenu popupMenu = new PopupMenu(context, more, Gravity.END);
        if (uid.equals(myuid)) {
            popupMenu.getMenu().add(Menu.NONE, 0, 0, "DELETE");
        }
        popupMenu.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
            @Override
            public boolean onMenuItemClick(MenuItem item) {
                if (item.getItemId() == 0) {
                    deltewithImage(pid, image);
                }
  
                return false;
            }
        });
        popupMenu.show();
    }
  
    private void deltewithImage(final String pid, String image) {
        final ProgressDialog pd = new ProgressDialog(context);
        pd.setMessage("Deleting");
        StorageReference picref = FirebaseStorage.getInstance().getReferenceFromUrl(image);
        picref.delete().addOnSuccessListener(new OnSuccessListener<Void>() {
            @Override
            public void onSuccess(Void aVoid) {
                Query query = FirebaseDatabase.getInstance().getReference("Posts").orderByChild("ptime").equalTo(pid);
                query.addValueEventListener(new ValueEventListener() {
                    @Override
                    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                        for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
                            dataSnapshot1.getRef().removeValue();
                        }
                        pd.dismiss();
                        Toast.makeText(context, "Deleted Sucessfully", Toast.LENGTH_LONG).show();
                    }
                    @Override
                    public void onCancelled(@NonNull DatabaseError databaseError) {
  
                    }
                });
            }
        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
  
            }
        });
    }
      
    private void setLikes(final MyHolder holder, final String pid) {
        liekeref.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                if (dataSnapshot.child(pid).hasChild(myuid)) {
                    holder.likebtn.setCompoundDrawablesWithIntrinsicBounds(R.drawable.ic_liked, 0, 0, 0);
                    holder.likebtn.setText("Liked");
                } else {
                    holder.likebtn.setCompoundDrawablesWithIntrinsicBounds(R.drawable.ic_like, 0, 0, 0);
                    holder.likebtn.setText("Like");
                }
            }
  
            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
  
            }
        });
    }
  
    @Override
    public int getItemCount() {
        return modelPosts.size();
    }
      
    class MyHolder extends RecyclerView.ViewHolder {
        ImageView picture, image;
        TextView name, time, title, description, like, comments;
        ImageButton more;
        Button likebtn, comment;
        LinearLayout profile;
  
        public MyHolder(@NonNull View itemView) {
            super(itemView);
            picture = itemView.findViewById(R.id.picturetv);
            image = itemView.findViewById(R.id.pimagetv);
            name = itemView.findViewById(R.id.unametv);
            time = itemView.findViewById(R.id.utimetv);
            more = itemView.findViewById(R.id.morebtn);
            title = itemView.findViewById(R.id.ptitletv);
            description = itemView.findViewById(R.id.descript);
            like = itemView.findViewById(R.id.plikeb);
            comments = itemView.findViewById(R.id.pcommentco);
            likebtn = itemView.findViewById(R.id.like);
            comment = itemView.findViewById(R.id.comment);
            profile = itemView.findViewById(R.id.profilelayout);
        }
    }
}

Step 3: Working with the fragment_home.xml file

Navigate to the app > res > layout > fragment_home.xml and add the below code to that file. Below is the code for the fragment_home.xml file. 

XML




<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".HomeFragment">
  
    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/postrecyclerview"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
  
</FrameLayout>

Step 4: Working with the HomeFragment.java file



This is how we will be retrieved blogs from Firebase. Every time data changes the value will change accordingly.

DatabaseReference databaseReference= FirebaseDatabase.getInstance().getReference("Posts");
        databaseReference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                posts.clear();
               for (DataSnapshot dataSnapshot1:dataSnapshot.getChildren()){
               }
            }

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

            Toast.makeText(getActivity(),databaseError.getMessage(),Toast.LENGTH_LONG).show();
       }
 });

Java




package com.example.socialmediaapp;
  
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;
  
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
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<ModelPost> 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();
            }
        });
    }
  
    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        setHasOptionsMenu(true);
        super.onCreate(savedInstanceState);
    }
      
}

Step 5: Create 2 new empty activities and name the activities as PostLikedByActivity and PostDetailsActivity. Keep the file as it is.

Output:

For all the drawable file used in this article please refer to this link: https://drive.google.com/drive/folders/1M_knOH_ugCuwSP5nkYzeD4dRp-Honzbe?usp=sharing

Below is the file structure after performing these operations:

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