Other than ViewModel, the mean that is used to communicate information back from ViewModel to Activity, the data in another word, also have the ability to be aware of the Activity's lifecycle. That's the reason is is call LiveData, data that is aware of the LiveCycle of the interested observer (e.g. Activity).Considering this, when should you not use LiveData?
When NOT to Use LiveData
- You need to use a lot of operators on data.
- You don't have UI interactions with data.
- You have one-shot asynchronous operations.
- You don't need to persist cached data into UI.
Beside above, what is the use of LiveData in Android? LiveData is a part of the architecture patterns. It's basically a data holder that contains primitive/collection types. It's used for observing changes in the view and updating the view when it is ACTIVE. Thus, LiveData is lifecycle aware.
Keeping this in view, how do you observe LiveData?
Attach the Observer object to the LiveData object using the observe() method. The observe() method takes a LifecycleOwner object. This subscribes the Observer object to the LiveData object so that it is notified of changes. You usually attach the Observer object in a UI controller, such as an activity or fragment.
What is the difference between LiveData and MutableLiveData?
MutableLiveData is a subclass of LiveData which is used for some of it's properties (setValue/postValue) and using these properties we can easily notify the ui when onChange() is called. Only using LiveData object we can't do this.
Is LiveData thread safe?
So, LiveData is immutable. MutableLiveData is LiveData which is mutable & thread-safe. So yes, the difference comes only by making postValue and setValue public.What is observer in Android?
The Observer Pattern is a software design pattern that establishes a one-to-many dependency between objects. Anytime the state of one of the objects (the "subject" or "observable") changes, all of the other objects ("observers") that depend on it are notified.What is Android architecture?
Android architecture is a software stack of components to support a mobile device needs. Android software stack contains a Linux Kernel, collection of c/c++ libraries which is exposed through an application framework services, runtime and application.What is Mvvm Android?
Model-View-ViewModel (ie MVVM) is a template of a client application architecture, proposed by John Gossman as an alternative to MVC and MVP patterns when using Data Binding technology. Its concept is to separate data presentation logic from business logic by moving it into particular class for a clear distinction.What is mutable LiveData?
LiveData is part of Android Architecture Components released by Google. It is an Observable(it follows observer pattern) class that holds data of type that you specify. LiveData takes in an observer and notifies it about data changes only when it is in STARTED or RESUMED state.What is view model in ASP NET MVC?
ViewModel serves this purpose. View Model is a model class that can hold only those properties that is required for a view. It can also contains properties from more than one entities (tables) of the database. As the name suggests, this model is created specific to the View requirements.Is ViewModel Life Cycle Aware?
LifecycleOwner is an interface that is used by any class that has an Android lifecycle. Practically, it means that the class has a Lifecycle object that represents its lifecycle. Both ViewModel and LiveData can bind to a Lifecycle .How does ViewModel survive change configuration?
The ViewModel class is designed to store and manage UI-related data in a lifecycle conscious way. The ViewModel class allows data to survive configuration changes such as screen rotations. Architecture Components provides ViewModel helper class for the UI controller that is responsible for preparing data for the UI.How do I get ViewModel in fragment?
Use activity's scope to create an instance of the ViewModel in fragment so that all the fragments and activity now has a common ViewModel and have access to the same ViewModelStore . If the activity is re-created, it and all its fragments receive the same ViewModel instance that was created by the associated activity.What is RxJava used for?
Why should we use RxJava on Android. Reactive Extensions (Rx) are a set of interfaces and methods which provide a way to developers solve problems rapidly , simply to maintain, and easy to understand. RxJava provides just that, a set of tools to help you write clean and simpler code.What is MediatorLiveData?
android.arch.lifecycle.MediatorLiveData<T> LiveData subclass which may observe other LiveData objects and react on OnChanged events from them. This class correctly propagates its active/inactive states down to source LiveData objects.What is data binding in Android?
Data Binding Library Part of Android Jetpack. The Data Binding Library is a support library that allows you to bind UI components in your layouts to data sources in your app using a declarative format rather than programmatically. Layouts are often defined in activities with code that calls UI framework methods. 
