p69 / dartea Goto Github PK

With the following dependency setting in pubspec.yaml, Dart complains DarteaMessageBus isn't defined. I tried modifying the yaml file to reference the github repo (git:), and also tried putting a copy of the repo in the root folder (path: ../dartea) of my project to no avail.

dartea: "^0.6.1"

What could I be missing?

Hello, i have no idea how to catch Scaffold from context in this situation:

Widget _view(
    BuildContext ctx, Dispatch<CaseEdMsg> dispatch, CaseEdModel model) {
  return Scaffold(
    appBar: AppBar(
      title: Text('Editor'),
    ),
    body: Container(
      padding: EdgeInsets.all(8),
      child: SomeButton(
          onPressed: () {
               Scaffold.of(ctx).showSnackBar(); /// Here
          },
);

Where can i intercept Scaffold?

To reproduce:

Program(
  view: (c,d,m) => TextField(key: GlobalKey())
  init: () => Upd(null),
  update: (msg, m) => Upd(null),
);

Each time you try to focus TextField it rebuilds and thus unfocuses. Without GlobalKey specified that is not a problem.

We have

    return ProgramWidget(
      init: _init,
      update: (msg, model) => _update(msg, model),
      view: _view,
      withMessagesBus: true,
    );

where init has signature without any custom parameters.
What if one need pass some?

Am loving this approach.
The fractal self similar aspect is create.

One concern I have is about performance. When a data change occurs is it updating all of the widgets , even though only one widget is affected by the data change ? I am not sure.

Hi, I'm getting the above error as I try to introduce 'effects' to one of my messages for http calls. (The program before this change worked fine just dealing with Model changes.)

The stack trace doesn't refer directly to my codes, so I'm a bit lost what to fix, so your help will be much appreciated.

FYI. Someone on the internet thought the following lines in Dartea's widget.dart might be the issue, because "our onError handler is passed Errors and Exceptions, but you strictly restrict it to Exceptions, that's the problem." but I'm not sure if it's right or not.

    _appLoopSub = updStream
        .handleError((e, st) => program.onError(st, e))

E/flutter ( 541): [ERROR:flutter/shell/common/shell.cc(186)] Dart Error: Unhandled exception:
E/flutter ( 541): type 'NoSuchMethodError' is not a subtype of type 'Exception'
E/flutter ( 541): #0 _DrateaProgramState.initState.
../…/src/widget.dart:68
E/flutter ( 541): #1 _invokeErrorHandler (dart:async/async_error.dart:14:37)
E/flutter ( 541): #2 _HandleErrorStream._handleError (dart:async/stream_pipe.dart:286:9)
E/flutter ( 541): #3 _ForwardingStreamSubscription._handleError (dart:async/stream_pipe.dart:168:13)
E/flutter ( 541): #4 _RootZone.runBinaryGuarded (dart:async/zone.dart:1326:10)
E/flutter ( 541): #5 _BufferingStreamSubscription._sendError.sendError (dart:async/stream_impl.dart:355:15)
E/flutter ( 541): #6 _BufferingStreamSubscription._sendError (dart:async/stream_impl.dart:373:16)
E/flutter ( 541): #7 _BufferingStreamSubscription._addError (dart:async/stream_impl.dart:272:7)
E/flutter ( 541): #8 _SyncStreamController._sendError (dart:async/stream_controller.dart:768:19)
E/flutter ( 541): #9 _StreamController._addError (dart:async/stream_controller.dart:648:7)
E/flutter ( 541): #10 _StreamController.addError (dart:async/stream_controller.dart:600:5)
E/flutter ( 541): #11 _RootZone.runBinaryGuarded (dart:async/zone.dart:1326:10)
E/flutter ( 541): #12 _BufferingStreamSubscription._sendError.sendError (dart:async/stream_impl.dart:355:15)
E/flutter ( 541): #13 _BufferingStreamSubscription._sendError (dart:async/stream_impl.dart:373:16)
E/flutter ( 541): #14 _BufferingStreamSubscription._addError (dart:async/stream_impl.dart:272:7)
E/flutter ( 541): #15 _ForwardingStreamSubscription._addError (dart:async/stream_pipe.dart:137:11)
E/flutter ( 541): #16 _ForwardingStream._handleError (dart:async/stream_pipe.dart:102:10)
E/flutter ( 541): #17 _ForwardingStreamSubscription._handleError (dart:async/stream_pipe.dart:168:13)
E/flutter ( 541): #18 _RootZone.runBinaryGuarded (dart:async/zone.dart:1326:10)
E/flutter ( 541): #19 _BufferingStreamSubscription._sendError.sendError (dart:async/stream_impl.dart:355:15)
E/flutter ( 541): #20 _BufferingStreamSubscription._sendError (dart:async/stream_impl.dart:373:16)
E/flutter ( 541): #21 _BufferingStreamSubscription._addError (dart:async/stream_impl.dart:272:7)
E/flutter ( 541): #22 _ForwardingStreamSubscription._addError (dart:async/stream_pipe.dart:137:11)
E/flutter ( 541): #23 _addErrorWithReplacement (dart:async/stream_pipe.dart:188:8)
E/flutter ( 541): #24 _MapStream._handleData (dart:async/stream_pipe.dart:229:7)
E/flutter ( 541): #25 _ForwardingStreamSubscription._handleData (dart:async/stream_pipe.dart:164:13)
E/flutter ( 541): #26 _RootZone.runUnaryGuarded (dart:async/zone.dart:1314:10)
E/flutter ( 541): #27 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:336:11)
E/flutter ( 541): #28 _DelayedData.perform (dart:async/stream_impl.dart:591:14)
E/flutter ( 541): #29 _StreamImplEvents.handleNext (dart:async/stream_impl.dart:707:11)
E/flutter ( 541): #30 _PendingEvents.schedule. (dart:async/stream_impl.dart:667:7)
E/flutter ( 541): #31 _microtaskLoop (dart:async/schedule_microtask.dart:41:21)
E/flutter ( 541): #32 _startMicrotaskLoop (dart:async/schedule_microtask.dart:50:5)

Here are the relevant parts of my code.

class FetchHttp implements Message {}
...

else if (msg is FetchHttp) {
    final fetchCmd = Cmd.ofAsyncFunc(() => httpFunc("query"),
        onSuccess: (res) => HandleHttpResponse(res),
        onError: (_) => HandleHttpResponse(null));

    return Upd(model.copyWith(todo: model.todo), effects: fetchCmd);
  }

....

Future<String> httpFunc(String query) async {
  final response = await _client.post(_searchUrl(query));
  if (response.statusCode == 200) {
    return response.body;
  }
  throw Exception('failed to load todos');
}

....

Have you figured out a way to generate copyWith so it does not have to be created manually by hand? built_value offer this solution but it's pretty ugly to use.

just like this repo:
https://github.com/felangel/Bloc

It separates to three packages: bloc, flutter_bloc and angular_bloc,

Hopefully there would also be examples for AnguarDart usage with dartea !

We have DarteaStorageKey for storing state.
But periodically one need to force to update widgets upon some circumstances.
Are there recipes or how-to for this cases?

Not an issue but a question.

What do you recommend for routing for SPA's using Dartea?
Something like Elm's Navigation module for Dart?

Could a ProgramWidget bind two or more models?
My view may corresponds to many models, for example, teacher's model, student's model,

If only one model could be bound to a ProgramWidget, although we can send msg(by msgsToBus) to each other, but how can we access other model's fields?

I saw in the examples models and views are one-to-one, if we want to share business code with web code(for example AngularDart), and web client's view is different from mobile client's view(for example search view and detail view are merged into one page), reuse model code will be somehow cumbersome(although possible).

So, IMHO, another way to go would be using only one big model, and bind that model to a root widget(MaterialApp ? ), so that we could access model's fields and dispatch messages from everywhere.

Another question please. Is there a Dartea equivalent for Web? If not, do you have a plan to create one?

There's no constant named 'suspending' in 'AppLifecycleState'.
Try correcting the name to the name of an existing constant, or defining a constant named 'suspending'.

counter example main.dart
line 116

///Handle app lifecycle events, almost the same as [update] function
Upd<Model, Message> lifeCycleUpdate(AppLifecycleState appState, Model model) {
  switch (appState) {
    case AppLifecycleState.inactive:
    case AppLifecycleState.paused:
    case AppLifecycleState.suspending:
    //case AppLifecycleState.detached:
      return Upd(model.copyWith(autoIncrement: false));
    case AppLifecycleState.resumed:
    default:
      return Upd(model);
  }
}

I'm going to try replacing suspending with detached but please let me know what you think.

Please see here: https://www.reddit.com/r/flutterhelp/comments/qoxekt/tried_to_migrate_to_androidx_but_get_no_usages/

setState() is called on the root widget and it means that every widget in the tree should be rebuilt. Flutter is smart enough to make just incremental changes, but in general this is not so good.

This isn't true.
First of all, a setState on the root widget doesn't rebuild the whole widget tree.
Secondly, flutter doesn't do any sort of incremental change.

In flutter things are based around the class instance. If you reuse the same class instance as the old build call, flutter will stop any further build.

Which is why the following:

class _State extends State<Foo> {
  @override
  Widget build(BuildContext context) {
    Future.microtask( () => setState(() {}) );

    return widget.child
  }
}

will actually never force its child to rebuild even if it updates every frames.

Wolud you be so kind to give me receipt how can i do next:
When DataModel finishes some work i'd like to instantiate and send Message from another one, i.e. HistoryCreateMsg from HistoryModel.

So which the right approach?

DataModel
-> DataCreateMsg
–> HistoryCreateMsg 

HistoryModel
* HistoryCreateMsg