Saving Data on Android

Loading State
: Displayed when the list of questions are being loaded from your 
database and it is represented by a progress bar:
•
Data State
: Displayed when you are ready to display a question to your user. This 
state is represented by a text and a group of radio buttons for the options:
Saving Data on Android Chapter 9: Using Room with Google's Architecture Components
raywenderlich.com
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•
Empty State
: Displayed when there are no questions in your database. This state 
is represented by an image and a text saying that there are no questions:
•
Finish State
: A special state, sent from the 
ViewModel
 when there are no more 
questions to be displayed. This state is only used by the 
QuestionActivity
 to 
know when to navigate to the 
ResultActivity
.
To represent the above states you are going to create a sealed class that your 
ViewModel
 will update and the 
QuestionActivity
 will observe using 
LiveData
. In 
the end, you will have an architecture like this:
Your 
View
s will only be in charge of communicating the actions from the user to 
your 
ViewModel
 and rendering the data received. The ViewModel will be in charge of 
communicating with the repository, handling the logic and sending UI ready data to 
your 
View
. Interesting huh? :]
Create a new Kotlin class under the