Singleton NStack instance to expose business logic features

[johsoe]

Today NStack on Flutter is provided through the widget tree only on the BuildContext.

We want to expose a Singleton NStack object, that can:

• Change the language in the domain layer
• Send Feedback
• Send Rate Reminder actions, ask for Rate Reminder state
• Fetch Collections
• Fetch Version Control state (and expose that via the BuildContext)
• Fetch Terms state (and expose that via the BuildContext)

It would be cool to look at other SDK's for inspiration.

We could make a facade Singleton with a reference to the currently file private _nstack instance, but there might be better solutions out there.

[nivisi]

@johsoe

Refactoring

Localization

As we're expanding capabilities of the generated NStack object, I think we must rename the NStack class. Currently it only holds localization data, so it can be named NStackLocalization.

All other features will be named in a similar way: NstackFeedback, NStackRateReminder etc. Users of the package will work with a high level object that will store all the features. The object will be of a class called NStackSdk, and it will be available though a global variable called NStack.

In the generated code, it will be:

final _localization = NStackLocalization(
  /* Configuration that we have atm */
);

final _feedback = NStackFeedback(
  /* Configuration of feedback if needed */
);

/* other features */

Here's our global singleton:

final NStack = NStackSdk(
  localization: _localization,
  feedback: _feedack,
  // etc
);

This is how we can access it:

// In a bloc or whatever

import 'package:app/nstack/nstack.dart';

void accessNstack() {
  print(NStack.localization.defaultSection.helloWorld);
}

Accessing other features via a BuildContext

We can introduce an extension to access NStack from a BuildContext similar to what we have with localization.

// Can be like this (I'm for it)
context.nstack.feedback;
context.nstack.terms;

// Or like this:
context.feedback;
context.terms;

Accessing features in the domain layer

Changing locale

We already have the Language class in the NStack SDK. We can work with it in the domain layer.

void changeLocale() {
  NStack.localization.changeLanguage(language);
}

Optionally, we can generate the list of available languages as a class named AvailableLanguages so it can be accessed like this:

  NStack.localization.availableLanguages.english
  NStack.localization.availableLanguages.dutch
  NStack.localization.availableLanguages.values // will return a list of all the languages

And the NStackLocalization will use this Language object to map it to a Flutter's Locale object and notify the UI.

We could also do it from the UI layer like this:

final availableLanguages = context.localization.availableLanguages.values; // will watch for the list

return ListView.builder(
  itemsCount: availableLanguages.length,
  builder: (context, index) {
    final language = availableLanguages.elementAt(index);
    
    return TextButton(
      onTap: () {
        context.nstack.changeLanguage(language);
      },
      child: Text(language.getName(context)),
    );
  },
);

Asking for feedback

In a BLoC we could easily ask for feedback like this:

Future<void> saveRecord() async {
  /* Do save */

  NStack.feedback.askIfNeeded();

  // It can either do it automatically under the hood,
  // or we can provide a callback with a FeedbackData object
  // that will contain user's input.
  NStack.feedback.askIfNeeded(
    onSubmitted: (data) { /* Do sth with user feedback */ }
  );
}

askIfNeeded (or whatever) will make the NStackWidget to trigger the UI to show the feedback popup.

NStackWidget can provide ability to configure how the popup looks like:

NStackWidget(
  platformOverride: blabla,
  feedbackPopupBuilder: (context, onSubmit /* Other params? */) {
    return BrandFeedbackDialog(onSubmit: onSubmit);
  },
  onFeedbackSubmitted: (context) {
    ShowToast('Thank you for your feedback!');
  },
  child: child,
);

[johsoe]

NStackWidget can provide ability to configure how the popup looks like:

NStackWidget(
  platformOverride: blabla,
  feedbackPopupBuilder: (context, onSubmit /* Other params? */) {
    return BrandFeedbackDialog(onSubmit: onSubmit);
  },
  onFeedbackSubmitted: (context) {
    ShowToast('Thank you for your feedback!');
  },
  child: child,
);

It's important that we make the feedback functionality super flexible, so I think I prefer splitting out the FeedbackDialog thingie in its own widget with custom builder maybe if needed. What do you think?

[johsoe]

Otherwise good considerations and approach, lets try it out 👍

[nivisi]

It's important that we make the feedback functionality super flexible, so I think I prefer splitting out the FeedbackDialog thingie in its own widget with custom builder maybe if needed. What do you think?

Nvm, I mixed it up with rate reminder 😄 Totally agree about a separate widget for the feedback feature. Could be NStackFeedbackDialog to ensure the "context" is kept