The only difference is in the syntax of emitting state. You can swap “cubit” in the picture above and nothing will change. This approach is literally the same as State Notifier from a developer’s perspective. As illustrated by Bloc authors, the workflow of Cubit looks the following way: The reason being is that Cubit while being a bit simplified version of Bloc, looks and feels exactly the same way as State Notifier for a developer. Bloc/Cubit and State Notifierįirst of all, we are going to throw out Cubit from this comparison. Let’s start by comparing the state management packages. Riverpod on the other hand is literally Provider 2.0 for DI and has a State Notifier package bundled with it for state management (and the name Riverpod is an anagram of the Provider for the reason that it’s next generation Provider). Both of these packages can be virtually split into two parts: dependency injection and state management.īloc uses its own extensions of the Provider package for DI and Bloc or Cubit classes for storing state. Riverpod and Bloc are the most prominent packages which promote an immutable state (meaning that you cannot change the state of the app from the UI, so you eliminate the possibility of a rogue code behaving unpredictably).Ĭomparing Riverpod and Bloc is not strictly a correct approach. There are countless threads on Twitter and Reddit posts that pitch one solution against another or preach a pure solution of only using Flutter-provided classes like ChangeNotifier, but when it comes to real-life products, you have to decide on a stack of third parties and approaches that would be most beneficial to your team and your app. The reason is that in order to combine the two input streams, we need to read the entire userFavourites collection.įirestore top tip: collection listeners are updated when we write any of the documents inside them.Īs a result, the entire list of movies is rebuilt when we favourite a single movie.One of the most actively asked questions from Flutter beginners is “What is the best state management library?”. In fact, the combineLatest approach leads to more widget rebuilds than when using nested StreamBuilders. The solution using combineLatest has some benefits, because we can easily combine data and lift some logic out of the UI layer.Īnd this means that our widgets become simpler.īut the devil is in the details. finally the StreamBuilder gets a new snapshots and rebuild the UIĬomparison: Nested StreamBuilders vs combineLatest.combineLatest2 combines this with the movies data to produce a new output.this in turn pushes a new stream value into our data flow.the users/$uid/userFavourites collection is updated. When the favourite data is written in Firestore: To show the data, we can use a StreamBuilder to get the stream and rebuild a ListView every time the data changes:Ĭlass MovieListItem extends StatelessWidget Īs a reminder, here's the complete system diagram for our simple app:Īs we can see, there is a read-and-write loop in our data flow, which causes our UI to rebuild when the user toggles the favourite flag on a movie. To show this data in a Flutter app, can parse all these documents into a list of Movie objects, and make them accessible with a Stream>. Each document is a movie, and it contains the title, a description, and possibly some other metadata. This is represented as a top-level collection in Firestore. Let's suppose that we want to show a list of movies. This tutorial will include the most relevant code snippets, but you can find the full source code on GitHub, and see how everything fits together. We will explore two ways of doing this, and discuss the pros and cons at the end.
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