Room + ViewModel + LiveData + RecyclerView (MVVM) Part 4 - REPOSITORY - Android Studio Tutorial

author Coding in Flow   4 мес. назад

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Room + ViewModel + LiveData + RecyclerView (MVVM) Part 5 - VIEWMODEL - Android Studio Tutorial

In part 5 of the Architecture Components tutorial, we will create our Viewmodel class. The ViewModel works as a gateway between the UI controller and the repository. It stores and processes data for the activity/fragment and it doesn't get destoyed on configuration changes, so it doesn't lose it's variable state for example when the device is rotated. By extending AndroidViewModel, we get a handle to the application context, which we then use to instantiate our RoomDatabase. In our activity we let the system provide us the correct ViewModel instance by calling ViewModelProviders.of, where we pass the Activity or Fragment this ViewModel's lifecycle should be scoped to. When our Activity/Fragment is then destroyed, the ViewModel will go through it's onCleared method and get removed from the memory. In our activitie's onCreate method, we retrieve the LiveData that is stored in our ViewModel and call observe on it, where we pass a LifecycleOwner and an Observer. In the onChange callback we get an update on our data whenever something in the corresponding database table changes. The LiveData will automatically start and stop sending updates to our activity at the right time in it's lifecycle and clean up any unused references. Watch the whole playlist: Example code, dependencies & instructions: ____________________ Subscribe to my channel: Want more Android tutorials? Check my playlist section: Follow me on social media: Facebook: Instagram: Twitter: Blog:

Desain Peta 3D dengan CorelDRAW - Tutorial Coreldraw

Tutorial CorelDraw Cara Desain Peta 3D dengan CorelDRAW, 3D Map, Denah Lokasi, desain peta undangan. Disampaikan secara detail dan mudah dipahami. Subscribe (Berlangganan) GRATIS : Download File Master CDR dan Elemen Pendukung : ---------------------------------- Playlist Tutorial : CorelDraw Basic : CorelDraw Tutorial : Photoshop Basic : Photoshop Tutorial : Tips & Trik : ----------------------------------- Medsos : Facebook : Instagram : Twitter : Semoga Bermanfaat

droidcon NYC 2017 - Reactive, Clean Architecture and Android Architecture Components..

Reactive, Clean Architecture and Android Architecture Components, a solid formula for a MVVM based architecture. Lucia Payo, N26 Reactive development that links long-lived objects with pure functions is hot for good reason. Clean architecture helps with the separation of concerns making our code unit testable and separated from the framework. The recently released Android Architecture Components, and more specifically, the LiveData and ViewModel, make it easy to connect to the framework. If we mix this three and add some sparks of Dagger on top we get a solid formula for a Model-View-ViewModel based architecture. The talk starts with a reminder of the characteristics any good architecture should have. This characteristics include: testability, separation of concerns, modularity, among some other good practices. The next step is to cover the three layers from clean architecture: - Data: This is the layer that keeps the entities. We’ll show how to create a fully reactive data layer that serves the entities in streams. - Domain: This is a connection layer that holds the business logic to create use cases. We’ll show how to make it stateless and 100% free of framework code. - Presentation: This is the layer where the new LiveData and ViewModel classes come into play. We will show how to transform the use cases from the domain layer into view specific models using the new android architecture components. The goal of the talk is to provide insights and guidelines on how to build a solid MVVM based reactive architecture. There will be links to meaningful resources that will cover the topics of the talk, like a GitHub example project and blog posts. droidcon NYC - ********************************************* droidcon NYC has become an event where the American and International Android development and design community come together to share what’s new and what they’ve been working on. Our goal is to serve the community and move the Android platform forward. Organized by droidcon - ********************************************* droidcon is the largest global network of developer conferences which bring together the industry's foremost experts dedicated to advancing the Android platform. droidcon engages a global network of over 25,000 developers attending our events in 26 countries. Content by touchlab - ********************************************* droidcon NYC content organized by Kevin Galligan, President of touchlab Android and iOS Mobile App Development / Doppl Open Source Code Sharing Platform / Mobile Innovation Advisory / UIUX Design. Our goal is to keep growing our company by serving the community. Stop by our next meetup: Big thanks to our video sponsors: American Express - mParticle -

Android Kotlin: Forecast App 05 - Repository & Kodein Dependency Injection - MVVM Tutorial Course

📗 Get the code from this tutorial 👇👇 Repository is a class which puts the network and local data operations into a centralized place. Repository is also a place for orchestrating the data caching. We don't need to fetch data from the network every time the user launches our app. If the local data is relatively up-to-date, we can use it instead. In this part the series you are going to learn how to create such a repository. You're also going to learn how to finally set up the dependency injection so that we are prepared for the next part. Go to my website for more information, code examples and articles: ● Follow me on social media: ● ● ● ●

In part 4 of the Architecture Components tutorial, we will create our Repository. The Repository ist a simple Java class that abstracts the data layer from the rest of the app and mediates between different data sources, like a web service and a local cache. It hides the different database operations (like SQLite queries) and provides a clean API to the ViewModel.
Since Room doesn't allow database queries on the main thread, we use AsyncTasks to execute them asynchronously.
LiveData is fetched on a worker thread automatically, so we don't have to take care of this.
Also, we will add a RoomDatabase.Callback to our database builder where we populate our database in the onCreate method so we don't start with an empty table. We can also override onOpen if we want to execute code every time our Room database is opened.

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