我正在创建一个社交消息应用程序。 将消息保存到Firebase数据库，然后在RecyclerView上显示的方式是应用功能的理想选择。消息已保存到数据库，但不显示在RecyclerView上。
请帮助...
谢谢
消息采用者类。
public class MessagesAdopter extends RecyclerView.Adapter {
public MessagesAdopter(List<Messages> messagesList) {
}
@NonNull
@Override
public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
return null;
}
@Override
public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
}
@Override
public int getItemCount() {
return 0;
}
public class MessageAdopter extends RecyclerView.Adapter<MessageAdopter.MessageViewHolder> {
private List<Messages> usersmessengeslist;
private FirebaseAuth mAuth;
private DatabaseReference userdatabaseref;
public MessageAdopter (List<Messages> usersmessengeslist){
this.usersmessengeslist = usersmessengeslist;
}
public class MessageViewHolder extends RecyclerView.ViewHolder {
private TextView sender_typed_message,reciever_typed_message;
CircleImageView reciever_image_view;
public MessageViewHolder(@NonNull View itemView) {
super(itemView);
sender_typed_message = itemView.findViewById(R.id.sender_typed_message);
reciever_typed_message = itemView.findViewById(R.id.reciever_typed_message);
reciever_image_view = itemView.findViewById(R.id.reciver_profile_image);
}
}
@NonNull
@Override
public MessageViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View V = LayoutInflater.from(parent.getContext())
.inflate(R.layout.users_message_layout,parent ,false);
mAuth = FirebaseAuth.getInstance();
return new MessageViewHolder(V);
}
@Override
public void onBindViewHolder(@NonNull final MessageViewHolder holder, int position) {
String messagesenderid = mAuth.getCurrentUser().getUid();
Messages messages = usersmessengeslist.get(position);
String fromUserID = messages.getFrom();
String frommessagetype = messages.getType();
userdatabaseref = FirebaseDatabase.getInstance().getReference().child("Users").child(fromUserID);
userdatabaseref.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()){
String image = dataSnapshot.child("profileimage").getValue(String.class);
Picasso.get().load(image).placeholder(R.drawable.profile).into(holder.reciever_image_view);
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
if (frommessagetype.equals("text")){
holder.reciever_image_view.setVisibility(View.INVISIBLE);
holder.reciever_typed_message.setVisibility(View.INVISIBLE);
if (fromUserID.equals(messagesenderid)){
holder.sender_typed_message.setBackgroundResource(R.drawable.sender_message_background);
holder.sender_typed_message.setTextColor(Color.WHITE);
holder.sender_typed_message.setGravity(Gravity.LEFT);
holder.sender_typed_message.setText(messages.getMessage());
}
else
{
holder.sender_typed_message.setVisibility(View.INVISIBLE);
holder.reciever_typed_message.setVisibility(View.VISIBLE);
holder.reciever_image_view.setVisibility(View.VISIBLE);
holder.reciever_typed_message.setBackgroundResource(R.drawable.reciever_message_background);
holder.reciever_typed_message.setTextColor(Color.WHITE);
holder.reciever_typed_message.setGravity(Gravity.LEFT);
holder.reciever_typed_message.setText(messages.getMessage());
}
}
}
@Override
public int getItemCount() {
return usersmessengeslist.size();
}
}
}
聊天活动：
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_chat);
mAuth = FirebaseAuth.getInstance();
messagesenderuserIdD = mAuth.getCurrentUser().getUid();
RootRef = FirebaseDatabase.getInstance().getReference();
recievereruserid = getIntent().getExtras().get("visit_user_id").toString();
recieverrusername = getIntent().getExtras().get("userName").toString();
iniitializefeildz();
displayrecieveruserinformtion();
sendmessagebutton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
sendusermessage();
}
});
fetchmessage();
}
private void fetchmessage() {
RootRef.child("Messages").child(messagesenderuserIdD).child(recievereruserid)
.addChildEventListener(new ChildEventListener() {
@Override
public void onChildAdded(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
Messages messages = dataSnapshot.getValue(Messages.class);
mMessagesList.add(messages);
MessagesAdopter.notifyDataSetChanged();
}
@Override
public void onChildChanged(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
}
@Override
public void onChildRemoved(@NonNull DataSnapshot dataSnapshot) {
}
@Override
public void onChildMoved(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
}
private void sendusermessage() {
String messagetext = user_inout_message.getText().toString();
if (TextUtils.isEmpty(messagetext)){
Toast.makeText(chatActivity.this,"please type a message",Toast.LENGTH_SHORT).show();
}
else {
String message_sender_ref = "Messages/" + messagesenderuserIdD + "/" + recievereruserid;
String message_reciever_ref = "Messages/" + recievereruserid + "/" + messagesenderuserIdD;
DatabaseReference user_message_key = RootRef.child("Message").child(messagesenderuserIdD).child(recievereruserid).push();
String message_push_id =user_message_key.getKey();
Calendar callforddate = Calendar.getInstance();
SimpleDateFormat currentdate =new SimpleDateFormat("dd-MMMM-yyyy");
savecurrentdate= currentdate.format(callforddate.getTime());
Calendar calFordTime = Calendar.getInstance();
SimpleDateFormat currentTime = new SimpleDateFormat("HH:mm");
savecurrenttime = currentTime.format(callforddate.getTime());
Map messageTextbody = new HashMap();
messageTextbody.put("Message", messagetext);
messageTextbody.put("time", savecurrenttime);
messageTextbody.put("date", savecurrentdate);
messageTextbody.put("type", "text");
messageTextbody.put("from", messagesenderuserIdD);
Map messageBodyDetails = new HashMap();
messageBodyDetails.put(message_sender_ref + "/"+ message_push_id,messageTextbody);
messageBodyDetails.put(message_reciever_ref + "/"+ message_push_id,messageTextbody);
RootRef.updateChildren(messageBodyDetails).addOnCompleteListener(new OnCompleteListener() {
@Override
public void onComplete(@NonNull Task task) {
if (task.isSuccessful()){
Toast.makeText(chatActivity.this,"message sent successfully",Toast.LENGTH_SHORT).show();
user_inout_message.setText("");
}
else {
String message = task.getException().getMessage();
Toast.makeText(chatActivity.this,"Error" + message,Toast.LENGTH_SHORT).show();
user_inout_message.setText("");
}
}
});
}
}
private void displayrecieveruserinformtion() {
chat_username.setText(recieverrusername);
RootRef.child("Users").child(recievereruserid).addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()){
final String profileimage = dataSnapshot.child("profileimage").getValue(String.class);
Picasso.get().load(profileimage).placeholder(R.drawable.profile).into(chat_circular_imageview);
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
}
private void iniitializefeildz() {
mToolbar = findViewById(R.id.action_cjat_bar);
setSupportActionBar(mToolbar);
ActionBar actionBar = getSupportActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setDisplayShowCustomEnabled(true);
LayoutInflater layoutInflater= (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View action_bar_view = layoutInflater.inflate(R.layout.chat_custom_appbar,null);
actionBar.setCustomView(action_bar_view);
chat_username = findViewById(R.id.user_chat_displayname);
chat_circular_imageview = findViewById(R.id.user_chat_displayimage);
user_inout_message= findViewById(R.id.chat_write_message_here);
sendmessagebutton = findViewById(R.id.send_chat_message);
sendimagemessage = findViewById(R.id.chat_chooseimage);
MessagesAdopter = new MessagesAdopter(mMessagesList);
messagesview = findViewById(R.id.messageview_list);
linearlayoutmanager = new LinearLayoutManager(this);
messagesview.setHasFixedSize(true);
messagesview.setLayoutManager(linearlayoutmanager);
messagesview.setAdapter(MessagesAdopter);
}
}
答案 0 :(得分：0)
嗨，我正在用Firebase数据库添加我的按摩，尝试用它可以帮助您：-
private void readMessage(final String myId, final String userId) {
mChat = new ArrayList<>();
reference = FirebaseDatabase.getInstance().getReference(chatTableName);
try {
reference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
mChat.clear();
Chat chat = null;
for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
chat = snapshot.getValue(Chat.class);
assert chat != null;
if (chat.getReceiver().equals(myId) && chat.getSender().equals(userId) ||
chat.getReceiver().equals(userId) && chat.getSender().equals(myId)) {
mChat.add(chat);
}
adapter = new MessageAdapter(UserMessageActivity.this, mChat);
recyclerView.setAdapter(adapter);
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
} catch (Exception e) {
Toast.makeText(this, "" + e.getMessage(), Toast.LENGTH_SHORT).show();
}
}