Nonetheless, it’s always showing the form, so a single class is enough to model this. Sometimes it shows the form with a loading indicator sometimes it shows the form with a snackbar sometimes it shows the form with one or two invalid fields. The screen contains only one type of state: It’s always showing the form. Now, for the sign-in screen, this will be very different - and a bit simpler: QuoteDetailsState Abstract base class QuoteDetailsInProgress QuoteDetailsFailure QuoteDetailsSuccess +quote: Quote Concrete implementation You used a class hierarchy to model this in an enum-like way: The screen was loading, showing an error or showing the quote - but never more than one at a time. Quick recap of the previous chapter: You create the state class to pack all the information your Cubit has to emit to your widgets, so they can rebuild themselves and reflect the new user state.įor example, the details screen you worked on in the last chapter had a few mutually exclusive types of state: While going through this chapter, you’ll work on the starter project from this chapter’s assets folder. Create a form that responds to different types of user interaction.Create reusable abstractions for your form fields.During that process, you’ll learn how to: They’re pretty much the same as far as their code goes, but since sign-in screens are the ones users see most, this is the one you’ll focus on for this chapter. WonderWords has a few different forms: the sign-in page, the sign-up page, the forgot password dialog and the update profile page. Avoiding unnecessary calls to the server if the data isn’t valid, which would cause delays and unnecessary data consumption.Making sure the user doesn’t flood the database with invalid data.Validating what the user types before sending it to the server serves at least two purposes: In fact, that’s where the bulk of the struggle comes from for screens: You have to keep track of what the user types, occasionally run some logic to make sure it’s in the expected format - a step known as validation - and meanwhile keep the user posted on the latest validation status of each field on the screen. Well, not quite whatever the user types: What if they enter an email in an invalid format? For example, this time, you won’t need to fetch data like you did for the details screen your job is now to send whatever the user types to the server. Managing the state of forms puts you in front of a whole different set of challenges. This chapter is level two, where you tackle forms. The next chapter, aka level three, handles the third type: the master screen. The previous chapter taught you how to use Cubits to manage the state of the first type: the details screen. When developing mobile apps, you’ll notice your screen types usually fall under one of these three buckets: Automating Test Executions & Build Distributionsġ5.3 Automating iOS Builds and Deployment Running Live Experiments With A/B Testing & Feature Flagsġ3.2 Logic Behind Remote Config and Feature Flagsġ3.4 Creating New Parameters in Firebase Remote Config Consoleġ3.5 Implementing UI Changes Based on Your Remote Config Supporting the Development Lifecycle With Firebase Creating Your Own Widget Catalogġ1.1 Why Do You Need a Component Library? Internationalizing & Localizingĩ.2 Generating Internationalization Filesĩ.4 Pluging Localization Classes Into MaterialApp Managing Complex State With Blocsĥ.1 Differentiating Between Cubits and BlocsĦ.4 Differentiating Between Ephemeral State and App StateĦ.5 Managing App State With BehaviorSubjectħ.3 Supporting Bottom Tabs With Nested RoutesĨ.4 Opening a Dynamic Link When Your App Is ClosedĨ.5 Opening a Dynamic Link When Your App Is Already Open Managing State With Cubits & the Bloc Libraryģ.9 Challenge 1: Downvoting, Unvoting, Favoriting and Unfavoriting Real-World Flutter by Tutorials Section 1: 16 chapters Show chapters Hide chaptersġ.5 Propagating the Configurations to the Following Chapters
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