How can i display the message from receiver in an chat application in android studio? - android-recyclerview

Question

We have programmed a chat application with Firebase in which the sender's messages are to be displayed on the right and those of the recipient on the left side.
The sender's messages are correctly displayed on the right side if you send the message with the Send button.
Unfortunately, the messages to the receiver are not shown on the left side.
Our Recyclerview java Code is this one:
package com.example.myapplicationsonet;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;
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.HashMap;
import java.util.List;
public class Message_recyclerview extends AppCompatActivity {
TextView tvUsername;
ImageButton ibtnSend;
EditText etMessage;
FirebaseUser fuser;
DatabaseReference databaseReference;
MessageAdapter messageAdapter;
List<message_helperclass> mChat;
RecyclerView recyclerView;
Intent intent;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate( savedInstanceState );
setContentView( R.layout.activity_message_recyclerview );
recyclerView = (RecyclerView) findViewById(R.id.rvmessage);
recyclerView.setHasFixedSize(true);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getApplicationContext());
linearLayoutManager.setStackFromEnd(true);
recyclerView.setLayoutManager(linearLayoutManager);
tvUsername = (TextView) findViewById(R.id.textView_message_username);
etMessage = (EditText) findViewById(R.id.messagebox);
ibtnSend = (ImageButton) findViewById(R.id.button_send);
intent = getIntent();
final String username = intent.getStringExtra("username");
fuser = FirebaseAuth.getInstance().getCurrentUser();
fuser = FirebaseAuth.getInstance().getCurrentUser();
databaseReference = FirebaseDatabase.getInstance().getReference("User").child(username);
databaseReference.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
tvUsername.setText(username);
readMessages(fuser.getUid(), username);
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
ibtnSend.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String msg = etMessage.getText().toString();
if (!msg.equals("")){
sendMessage(fuser.getUid(), username, msg);
}else {
Toast.makeText(Message_recyclerview.this, "Du kannst keine leeren Nachrichten versenden", Toast.LENGTH_LONG).show();
}
etMessage.setText("");
}
});
}
private void sendMessage(String sender, String receiver, String message ){
DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference();
HashMap<String, Object> hashMap = new HashMap<>();
hashMap.put("sender", sender);
hashMap.put("receiver", receiver);
hashMap.put("message", message);
databaseReference.child("Chats").push().setValue(hashMap);
}
private void readMessages(final String myid, final String username){
mChat = new ArrayList<>();
databaseReference = FirebaseDatabase.getInstance().getReference("Chats");
databaseReference.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
mChat.clear();
for (DataSnapshot snapshot : dataSnapshot.getChildren()){
message_helperclass chat = snapshot.getValue(message_helperclass.class);
if (chat.getReceiver().equals(myid) && chat.getSender().equals(username) ||
chat.getReceiver().equals(username) && chat.getSender().equals(myid)){
mChat.add(chat);
}
messageAdapter = new MessageAdapter(Message_recyclerview.this, mChat);
recyclerView.setAdapter(messageAdapter);
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
}
}
And this is our Adapter Class:
package com.example.myapplicationsonet;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import java.util.List;
public class MessageAdapter extends RecyclerView.Adapter<MessageAdapter.ViewHolder> {
public static final int MSG_TYPE_LEFT = 0;
public static final int MSG_TYPE_RIGHT = 1;
private Context mContext;
private List<message_helperclass> mChat;
FirebaseUser fUser;
public MessageAdapter(Context mContext, List<message_helperclass> mChat){
this.mChat = mChat;
this.mContext = mContext;
}
#NonNull
#Override
public MessageAdapter.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
if (viewType == MSG_TYPE_RIGHT){
View view = LayoutInflater.from(mContext).inflate(R.layout.chat_item_right, parent, false);
return new MessageAdapter.ViewHolder(view);
} else {
View view = LayoutInflater.from(mContext).inflate(R.layout.chat_item_left, parent, false);
return new MessageAdapter.ViewHolder(view);
}
}
#Override
public void onBindViewHolder(#NonNull ViewHolder holder, int position) {
message_helperclass chat = mChat.get(position);
holder.show_message.setText(chat.getMessage());
}
#Override
public int getItemCount() {
return mChat.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
public TextView show_message;
public ViewHolder(#NonNull View itemView) {
super(itemView);
show_message = itemView.findViewById(R.id.show_message);
}
}
#Override
public int getItemViewType(int position) {
fUser = FirebaseAuth.getInstance().getCurrentUser();
if (mChat.get(position).getSender().equals(fUser.getUid())){
return MSG_TYPE_RIGHT;
} else {
return MSG_TYPE_LEFT;
}
}
}
Unfortunately, we cannot find the error why the recipient messages are not displayed on the left.
I hope you can help us. It would be important.
Thanks!

Answer 1

Can't Comment, but have you checked your chat_item_right and chat_item_left XML file? Your code appears right so the error might be there.