我有片段，我有recyclerview，它在第一次启动时工作正常（当片段第一次启动时）。我可以发送和接收消息。但是当我从通知中转到聊天片段时，它会停止更新recyclerview。我必须从最近的应用程序清除应用程序，然后当我从通知聊天片段时，它工作正常。
每当我在点击通知后收到消息作为通知时，它会打开相同的聊天屏幕（先加载所有先前的消息），当我点击发送按钮发送消息时，它会发送给其他用户，但不会更新我的recyclerview。
正常加载聊天片段
getFragmentManager().beginTransaction().add(R.id.Navigation_Drawer, chatFragment).commit();
通过Asynctask从通知中加载片段
((Navigation_Drawer)context).getFragmentManager().beginTransaction().replace(R.id.Navigation_Drawer, chatFragment).commit();
ChatScreenFragment
public class Chat_Screen_Fragment extends Fragment implements View.OnClickListener, ChildEventListener{
public static final String TAG = "###CHAT SCREEN###";
List<Chat_Wrapper> 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()) {
// NOW GET ALL DATA FROM FIREBASE DATABASE AND SAVE IT INTO STRINGS THEN CHECK EACH BY ITS MESSAGE TYPE
Chat_Msg = (String) ((DataSnapshot) iterator.next()).getValue();
Chat_FROM = (String) ((DataSnapshot) iterator.next()).getValue();
Chat_FCM_TO= (String) ((DataSnapshot) iterator.next()).getValue();
Chat_Database tempChatDatabase = new Chat_Database(getActivity());
boolean hasValue=tempChatDatabase.CheckValueExist(_ID);
if (!hasValue) {
Log.d(TAG,"Chat 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 ");
return;
}
Chat_Wrapper chat_wrapper = new Chat_Wrapper(Chat_Msg, null, null, null, null, null, null, Chat_TimeStamp, User_Intent, UserImage_Intent, Chat_FROM, null,null,id);
message.add(chat_wrapper);
adapter.notifyDataSetChanged();
Log.d(TAG, "FIREBASE STORAGE PHOTO-3-MESSAGE ARRAY SIZE " + message.size());
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());
tempChatDatabase.isDatabaseClose();
}
adapter.notifyDataSetChanged();
recyclerView.post(new Runnable() {
@Override
public void run() {
Log.d(TAG, "Moving to Bottom");
recyclerView.smoothScrollToPosition(message.size()-1);
//recyclerView.smoothScrollToPosition(adapter.getItemCount());
}
});
}
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);
}
}
}
我还注意到，当我发表评论chatDatabase（）函数时，从本地数据库获取早期消息的方法工作正常。但仍无法解决问题。
完美无瑕。
chatDatabase()功能答案 0 :(得分：0)
当Fragment实例本身被保留时，它会在分离/替换时破坏并重新创建它的视图。
将您的firebase和适配器初始化逻辑移至onCreate，仅在RecyclerView中保留onCreateView初始化。
您还应该覆盖onDestroyView并清除对layoutManager和recyclerView的引用。
请注意，在这种情况下，您必须分离firebase回调或处理getView()（如果在recyclerView中清除引用的onDestroyView）为空并且然后跳过更新UI的情况。