This is the Part 13 of “Build a Social Media App on Android Studio” tutorial, and we are going to cover the following functionalities in this article:
- We are going to delete the Blog written by the user.
- Blogs can only be deleted by the owner of blogs. In the top right of the blog, a button is there.
- After clicking on that a popup will come in that Delete button will come. After clicking on Delete, the blog will be successfully deleted from the blogs.
Step By Step Implementation
Step 1: Working with the AdapterPosts.java file
We will get the node inside the “Posts” which we want to delete. We are directly deleting the snapshot reference value.
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();//removing the value after getting reference } pd.dismiss(); Toast.makeText(context,"Deleted Successfully",Toast.LENGTH_LONG).show(); } @Override public void onCancelled(@NonNull DatabaseError databaseError) { } });
Below is the updated code for the AdapterPosts.java file.
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<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);
}
}
} |
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: