How to Retrieve Blog On Home Page in Social Media Android App?

17 Jun, 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 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    xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:app="http://schemas.android.com/apk/res-auto"    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 Successfully", 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:android="http://schemas.android.com/apk/res/android"    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:
 
 
ruhelaa48
Firebase
Android
Java
Java
Android
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