Currency Rates

A sample Flutter app illustrating Sealed Classes usage.

The application displays currency rates from the National Bank of Poland via REST api. It uses Bloc library for the state management.

Events

• CurrencyRatesLoadEvent - informs the BLoC that it needs to load the currency rates,
• CurrencyRatesRefreshEvent - informs the BLoC that it needs to refresh the currency rates.

States

The UI can be in one of the following states:

• CurrencyRatesLoading - when currency rates are being loaded,
• CurrencyRatesLoaded - after the currency rates have been loaded successfully,
• CurrencyRatesRefreshing - when currency rates are being refreshed,
• CurrencyRatesError - when the currency rates haven't been loaded, because of an error.

Bloc

CurrencyRatesBloc in a response to the CurrencyRatesEvent retrieves currency rates from the repository and displays them on the UI.

Implementations

• Sealed Unions
• Sealed BLoC
• Sum Types
• Sealed Annotations
• Freezed