Recyclerview适配器的notifyDataSetChanged不更新RecyclerView

顾南

我有一个RecyclerView带有firebase实时数据库和本地数据库SQLite数据库聊天应用程序。我将消息保存到当地数据库（SQLite）中间，然后调用adapter.notifyDataSetChanged()。
如果消息在数据库中(唯一的消息)ID），则SQLite将在数据库insertOrThrow返回0 的方法。我正在检查这样的可用性。
if (id == 0) { Log.d(TAG,"Database Already Has Value Of This Random Id "); adapter.notifyDataSetChanged();} else Chat_Wrapper chat_wrapper = new Chat_Wrapper(Chat_Msg,null,null,null,null,null,null,Chat_TimeStamp,UserPhone_Intent,UserImage_Intent,Chat_FROM,null,null,id); message.add(chat_wrapper); adapter.notifyDataSetChanged();}但是，即使else正在调用这个句子，我的RecyclerView屏幕不会更新，但在后台，如果我输入或收到任何信息，它将保存在本地数据库中，但不会显示在屏幕上。
RecyclerView在以下情况下可以聊天
[ol]当我从最近的应用程序中删除应用程序时
停止从本地数据库获取数据
聊天屏幕首次启动[/ol]当我直接从通知中进入聊天屏幕时，我遇到了这个问题。
这就是我正常加载聊天片段的方式。
getFragmentManager().beginTransaction().add(R.id.Navigation_Drawer,chatFragment).commit();
加载Fragment从Notification使用Asynctask
((Navigation_Drawer)context).getFragmentManager().beginTransaction().replace(R.id.Navigation_Drawer,chatFragment).commit();这从通知开始ChatFragment的方式。
public class FireBase_Messaging_Service extends FirebaseMessagingService public static final String TAG="###FireBase MSG###"; public static final int NOTIFICATION=5; String UserName; String ID; String Msg; Map data; @Override public void onMessageReceived(RemoteMessage remoteMessage)       super.onMessageReceived(remoteMessage);       Log.d(TAG,"From " remoteMessage.getFrom()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；if (remoteMessage.getData().size()>()()()()())(             )data = remoteMessage.getData()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；Log.d(TAG,"Message Data " remoteMessage.getData());          data = remoteMessage.getData()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；UserName = data.get("name");          ID = data.get("ID");          Msg = data.get("Message");          showNotification(Msg,ID,UserName);       }       if (remoteMessage.getNotification()!=null)             Log.d(TAG,"Message Notification Body " remoteMessage.getNotification().getBody()；          Toast.makeText(this,"Notification " remoteMessage.getNotification().getBody(),Toast.LENGTH_LONG).show()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；private void showNotification(String Message,String ID,String UserName)             Log.d(TAG,"Show Notification " Message " " ID);       Intent intent=new Intent(this,Navigation_Drawer.class);       intent.putExtra("Type","Text");    intent.putExtra("Type",MsgType);       intent.putExtra("ID",ID);       intent.putExtra("uname",UserName);       intent.putExtra("Message",Msg);       intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_SINGLE_TOP);       PendingIntent pendingIntent=PendingIntent.getActivity(this,NOTIFICATION,intent,PendingIntent.FLAG_UPDATE_CURRENT);       int color = getResources().getColor(R.color.black);       String ChannelID = "Message";       notificationChannel(ChannelID,"Chat");       NotificationCompat.Builder builder = new NotificationCompat.Builder(getApplicationContext(),ChannelID)             .setSmallIcon(R.drawable.default_x)             .setColor(color)             .setContentTitle(UserName)             .setContentText(Message)             .setChannelId(ChannelID)             .setTicker("My App")             .setDefaults(Notification.DEFAULT_VIBRATE | Notification.DEFAULT_SOUND | Notification.FLAG_SHOW_LIGHTS)             .setLights(0xff00ff00,/ / To change Light Colors             .setStyle(new NotificationCompat.BigTextStyle().bigText(Message))//For Expandable View             .setPriority(NotificationCompat.PRIORITY_DEFAULT)             .setContentIntent(pendingIntent)             .setAutoCancel(true);       NotificationManagerCompat managerCompat = NotificationManagerCompat.from(this);       managerCompat.notify(NOTIFICATION,builder.build()；@Override public void onDeletedMessages()(){       super.onDeletedMessages()；       private void notificationChannel (String ChannelID,String channelName)             if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O)                NotificationChannel  channel = new NotificationChannel(ChannelID,channelName,NotificationManager.IMPORTANCE_DEFAULT);          channel.setLightColor(Color.GREEN);          NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);          notificationManager.createNotificationChannel(channel);    我还通过记录日志注意到，在将数据添加到列表中后，message.add(chat_wrapper)它首先显示了大小的增加，但当while循环结束时，它显示了的最后一个大小ArrayList。
这是ChatFragment课程。
public class Chat_Screen_Fragment extends Fragment implements View.OnClickListener,ChildEventListener{ public static final String TAG = "###CHAT SCREEN###"; List message = new ArrayList()；    Chat_Adapter adapter; RecyclerView recyclerView;
LinearLayoutManager layoutManager;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
      View v=inflater.inflate(R.layout.chat_screen_main_fragment,container,false);
      setRetainInstance(true);
   GET INTENT VALUES FROM USER PROFILE CLASS
      UserName_Intent = getArguments().getString("Get_Name");
      UserImage_Intent = getArguments().getString("Get_Image");
      UserPhone_Intent = getArguments().getString("Get_Phone");
      UserID_Intent = getArguments().getString("Get_ID");
      FirebaseToken_Intent = getArguments().getString("Get_Token"); //Firebase Token of other person
      Room_Name_Intent = getArguments().getString("Get_Other"); // Room Name of chat
      UserLastSeen_Intent=getArguments().getString("LastSeen");
   Sender_FCMToken = Session.getFirebaseID();
   RECYCLER VIEW
      recyclerView = v.findViewById(R.id.Chat_Screen_Message_List);
      layoutManager = new LinearLayoutManager(getActivity());
      layoutManager.setStackFromEnd(true);
      recyclerView.setHasFixedSize(true);
      recyclerView.setLayoutManager(layoutManager);
      databaseReference = FirebaseDatabase.getInstance().getReference().child(Room_Name_Intent);
      databaseReference.addChildEventListener(this);
      adapter = new Chat_Adapter(getActivity(), message);
      recyclerView.setAdapter(adapter);
   FETCH OLD MESSAGE FROM DATABASE
      chatDatabase();
      return v;
}
// FIREBASE REAL TIME DATABASE WHICH FETCH ALL MESSAGES (SYNC) FROM ONLINE DATABASE
@Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
      append_chat_conversation(dataSnapshot);
}
@Override
public void onChildChanged(DataSnapshot dataSnapshot, String s) {
      append_chat_conversation(dataSnapshot);
}
@Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
}
@Override
public void onChildMoved(DataSnapshot dataSnapshot, String s) {
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
private synchronized void append_chat_conversation(DataSnapshot dataSnapshot) {
      iterator = dataSnapshot.getChildren().iterator();
      while (iterator.hasNext()) {
   GETTING DATA FROM FIREBASE DATABASE
         Chat_Msg = (String) ((DataSnapshot) iterator.next()).getValue();
         Chat_FROM = (String) ((DataSnapshot) iterator.next()).getValue();
         Chat_FROM_ID = (String) ((DataSnapshot) iterator.next()).getValue();
         Chat_TO = (String) ((DataSnapshot) iterator.next()).getValue();
         Chat_TimeStamp = (String) ((DataSnapshot) iterator.next()).getValue();
         Chat_Type= (String) ((DataSnapshot) iterator.next()).getValue();
         Random_ID=(String) ((DataSnapshot) iterator.next()).getValue();
         Chat_FCM_FROM= (String) ((DataSnapshot) iterator.next()).getValue();
         Chat_FCM_TO= (String) ((DataSnapshot) iterator.next()).getValue();
         Log.d(TAG, "Chat Items " Chat_Msg " " Random_ID);
         Chat_Database tempChatDatabase = new Chat_Database(getActivity());
         boolean hasValue = tempChatDatabase.CheckValueExist(Random_ID);
         Log.d(TAG,"DATABASE ALREADY HAS VALUE OF TIMESTAMP= " hasValue);
         if (!hasValue) {
            Log.d(TAG,"DATABASE DON'T HAVE SAME ENTRY FOR TIME STAMP. ENTERED INTO HAS VALUE");
            Log.d(TAG,"Chat Message " Chat_Msg);
         if (Chat_Type.equals("Typed_Message")) {
            Log.d(TAG, "VIEW TYPE IS Message " Chat_Msg);
            long id = chat_database.Insert_Chat(Session.getUserID(),Room_Name_Intent, UserID_Intent, "Text", Chat_Msg, Chat_FROM, Chat_TO, Chat_TimeStamp, Chat_FCM_FROM, Chat_FCM_TO, Session.getPhoneNO(), UserPhone_Intent,Random_ID,UserImage_Intent,UserLastSeen_Intent,Chat_FROM_ID);
      Adding Chat Data Into Database
            Log.d(TAG,"Database Entry ID " id);
            if (id == 0) {
                  Log.d(TAG,"Database Already Has Value Of This Random Id ");
                  adapter.notifyDataSetChanged();
                  continue;
            } else {
                  Log.d(TAG,"Database Don't Has Value Of This Random Id ");
                  Log.d(TAG,"Message Size " message.size());
                  Chat_Wrapper chat_wrapper = new Chat_Wrapper(Chat_Msg, null, null, null, null, null, null, Chat_TimeStamp, UserPhone_Intent, UserImage_Intent, Chat_FROM, null,null,id);
                  message.add(chat_wrapper);
                  Log.d(TAG,"Message Size " message.size());
                  adapter.notifyDataSetChanged();
                  Log.d(TAG,"Adapter Notified Data Set " adapter.getItemCount());
                  recyclerView.post(new Runnable() {
                              @Override                      public void run()()(){                                                                                              Log.d(TAG,"Moving to Bottom");                         recyclerView.smoothScrollToPosition(adapter.getItemCount())；                                  ；；                                           Log.d(TAG,"MESSAGE ARRAY SIZE " message.size()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；chat_database.isDatabaseClose()；}    private void chatDatabase()()(){       Database Init and Filling Adapter       Log.d(TAG,"Chat Database Function");       chat_database=new Chat_Database(getActivity()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；chatCursor=chat_database.getUserChat(UserID_Intent);       boolean checkDB_Exist=functions.DatabaseExist(getActivity(),"CHAT_DATABASE.DB");       boolean chatItemsCounts=chatCursor.getCount()>0；          chatCursor.moveToFirst()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；Log.d(TAG,"Value At Chat Database "  checkDB_Exist " " chatItemsCounts);       if (checkDB_Exist && chatCursor.getCount()>0 && chatCursor.getString(chatCursor.getColumnIndex("RECEIVER_USER_ID")).equals(UserID_Intent))             Log.d(TAG,"Database Exist Chat Database");          message.clear()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；chatCursor.moveToFirst()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；do                   database_rowID=chatCursor.getInt(chatCursor.getColumnIndex("ID"));             database_userID=chatCursor.getString(chatCursor.getColumnIndex("USER_ID"));             database_RoomName =chatCursor.getString(chatCursor.getColumnIndex("ROOM_NAME"));             database_ReceiverID=chatCursor.getString(chatCursor.getColumnIndex("RECEIVER_USER_ID"));             database_MessageType=chatCursor.getString(chatCursor.getColumnIndex("MESSAGE_TYPE"));             database_Message=chatCursor.getString(chatCursor.getColumnIndex("USER_MESSAGE"));             database_MsgFrom=chatCursor.getString(chatCursor.getColumnIndex("SENDER_NAME"));             database_MsgTo=chatCursor.getString(chatCursor.getColumnIndex("RECEIVER_NAME"));             database_TimeStamp=chatCursor.getString(chatCursor.getColumnIndex("TIME_STAMP"));             database_FCMfrom=chatCursor.getString(chatCursor.getColumnIndex("SENDER_TOKEN"));             database_FCMto=chatCursor.getString(chatCursor.getColumnIndex("RECEIVER_TOKEN"));             database_LocalPath=chatCursor.getString(chatCursor.getColumnIndex("DOWNLOADED_AT"));             database_PhoneFrom=chatCursor.getString(chatCursor.getColumnIndex("MY_PHONE"));             database_PhoneTo=chatCursor.getString(chatCursor.getColumnIndex("OTHER_PHONE"));             Log.d(TAG,"Value Of Database Message String = " database_Message);             Log.d(TAG,"Row ID of Database " database_rowID);       Check Message Type                   Log.d(TAG,"Message Type Is Text");                   Chat_Wrapper text = new Chat_Wrapper(database_Message,null,null,null,null,null,null,database_TimeStamp,database_PhoneTo,UserImage_Intent,database_MsgFrom,null,null,database_rowID);                   message.add(text);                                  while(chatCursor.moveToNext()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；Room_Name_Intent = database_RoomName;          layoutManager = new LinearLayoutManager(getActivity()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；recyclerView.setLayoutManager(layoutManager);          adapter.notifyDataSetChanged()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；chatCursor.close()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；boolean value = chat_database.isDatabaseClose()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；recyclerView.post(new Runnable()(){             @Override             public void run()(){                Log.d(TAG,"Moving to Bottom");                   recyclerView.smoothScrollToPosition(message.size()-1)；                )；                Log.d(TAG,"Value Of Database Close or Not " value);
解决方案:

Recyclerview适配器的notifyDataSetChanged不更新RecyclerView

顾南 LV1