Dfyjkt

I have this app that has a start tutorial and I am saving in room database if the user already saw the tutorial. For that I save the data when the user finishes the tutorial and do a query in the onCreateMethod of the TutorialActivity to see if I skip to other activity. My DAO as two methods, one to insert and another to load. My load method(what I want to ask) has the following code:

@Query("SELECT * FROM tutorial LIMIT 1")
 fun load(): Single<TutorialEntity>

@Insert(onConflict = OnConflictStrategy.REPLACE)
fun insert(userEntity: TutorialEntity): Single<Long>

My entity:

@Entity(tableName = "tutorial")
class TutorialEntity (

 @PrimaryKey
 @ColumnInfo(name = "as_seen_tutorial")
 val asSeenTutorial: Long

)

This is my tutorial activity:

Note: I use dagger to inject the tutorialDao(not important here)

//here is where I check if the value is already 1 to skip
 onCreate()
 val load = tutorialDao.load()
 if(load.? contains 1) -> This is my doubt 
 //OBJECTIVE: does not show and skips to other activity 
 
 

//here is where I insert the flag into the database
fun showTutorial()
 val entity = TutorialEntity(1)
 tutorialDao.insert(entity)

I wanted to know how can I check if the value that cames from the select query is one

Well. I don't know if i understand you well but i had some questions before respond your doubt.

Why are you using a Single? (You are going to receive a NPE) (https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/single.html)

I recommend you to use just the class as nullable, so just check your variable for

if (load?.asSeenTutorial == 1) 
 // Do your stuff

And also remember that you need to do the insert operation under an AsyncTask.

While you can do this using Room, it is suggested that you better not use Room for such operations. These kinds of single value checks are done using SharedPreference.
Quoted by Google Documentation

If you have a relatively small collection of key-values that you'd like to save, you should use the SharedPreferences APIs.

With Room you have to consider creating @Entity, @Dao, call them in background thread. which are so much work

Here is how you do it with SharedPreference

val sharedPref = activity?.getSharedPreferences("AppPreference", Context.MODE_PRIVATE)

And you check it as below

if (sharedPref.getBoolean("as_seen_tutorial", false))
 // show tutorial. 
 // false is a default value

else
 // start another activity

And after showing your tutorial, you save "as_seen_tutorial" as true like below

with (sharedPref.edit()) 
 putBoolean("as_seen_tutorial", true)
 commit()