MessagesListController not able to clear items when enter chatPage again from another chatid

[luohao123]

Here is my code:

gLogger.i("init controller items: ${_controller.items.length}");
    _controller.items.clear();
    _controller.notifyChanges();
    _chatBloc.fetchLocalMsgsForSession(_chat.id);
    subscription = _chatBloc.crtChatMsgs.listen((event) {
      _controller.addAll(event);
      _controller.notifyChanges();
      gLogger.i("now controller items: ${_controller.items.length}");
    });

this is inside my initState function, so I want clear items every time enter a new chatPage. But it doesn't do this.

Normally, first log should be 0, and every time crtChatMsgs only fetechs 25 msgs from local. So everytime it enters chatPage, it should be 25 msgs.

However, first time:

this is normal, then I switch to another chatid (another chat page):

As u can see, second time the msg doesn't clear at all. It becomes 50, double of them. Normally, it should be fresh 25 msgs.

And the UI actually doesn't updated still contains data from previous chatid.

What could be the reason?

(I am new to flutter maybe I did something wrong but this lib is really useful, so I use it)

[jonasN5]

First off, I'm not sure I understand your flow. Usually to leave a ChatScreen, the user will go BACK and therefore pop the destination from the stack to return to ChatsScreen (the list of Chats), therefore also disposing the controller.

When you call _controller.items.clear();, it has nothing to do with the library. You're simply calling clear() on a dart list. The fact that you have 50 items instead of 25 after that indicates that you have a problem somewhere else, since clear() cannot fail. I suspect that it has something to do with the way you handle your controller. When accessing a new ChatScreen, you should create a new controller instance (which resets the items).

[luohao123]

vNot work even I add a clear at dispose!!!!!!
this is really bug!!

[luohao123]

@themadmrj I am currently found, even I re-enter same chatid page, the msg still increase, rather than first clear and then add only 25 msgs.

And my observation is that seems the stream call twice..... But I don't know why it called twice... I am gonna to cry about this.

Here is my code of navigate to detail:

final cp =
        ChatScreen(ChatScreenArgs(chat: chat, chatBloc: widget.chatBloc));
    var res = await Navigator.of(context)
        .push(CupertinoPageRoute(builder: (context) => cp));

[jonasN5]

Good old debugging process, just add print everywhere and eventually you'll find the problem!
Closing since solved/not related to library.

[luohao123]

I solved my problem, thanks!

[luohao123]

For future people might got this issue... I dont' plan to tell u guys..