vmiso 1.0.0

VMISO State Management (View Model, Inherited Store, Observer)

vmiso

VMISO State Management (View Model, Inherited Store, Observer)

Getting Started

VMISO provides super simple state management at the potential expense of some performance.

Currently being used in a number of small to mid scale production apps with no issues.

It works on the principle of maintaining a ViewModel class. Each time that should trigger an update call notify() and all Observers will update.

Under the hood it keeps to sound flutter principles - Observer is just a wrapper around StreamBuilder. Calling notify() passes the current class into a stream to an Observer. It probably sounds more complex than it is, check out the example below:

Simple ViewModel usage

///
/// make a change, call `notify()`
///
class ExampleViewModel extends ViewModel {
  String name;
  DateTime dateOfBirth;

  updateDateOfBirth(DateTime value) {
    dateOfBirth = value;
    notify();
  }
}

Using a getter and setter

///
/// You can also enable the view model to update all observers using a getter and setter.
///
/// Be careful doing this as it will trigger a redraw every time the variable is set.
///
class AutomaticNotification extends ViewModel {
  String _name;

  String get name => _name;

  set name(String name) {
    _name = name;
    notify();
  }
}

Observer Example usage

class ObserverExample extends StatelessWidget {
  final ExampleViewModel exampleViewModel;

  const ObserverExample({Key key, this.exampleViewModel}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Observer(
      viewModel: exampleViewModel,
      builder: (BuildContext context, AsyncSnapshot snapshot) {
        return Text(exampleViewModel.name); //You can just call the instance of the viewmodel or the snapshot.
      },
    );
  }
}

What about inherited store?

The initial goal was to create a wrapper around an inherited widget that streamlined the store, but because of Dart's lack of reflection I haven't been able to product the results I was hoping for.

Instead I have created and use a live template in Android Studio to quickly generate my "AppState" widget