Android - Type mismatch with LiveData variable

Question

I have the following in my viewmodel :

// hold the list of comments of a Post
private val _commentsOfPost = MutableLiveData<PagedList<Comment>>()

val commentsOfPost : LiveData<PagedList<Comment>> = _commentsOfPost

fun getCommentsOfPost(postId: Long){
     _commentsOfPost.value = commentRepository.getCommentsOfPost(postId)   // <--- TYPE MISMATCH
}

So, what happens is that whenever the getCommentsOfPost() is called by the Fragment, it retrieves a PagedList of Comment instances belonging to a Post specified by its ID.

But Android tells me about a Type mismatch ( see the arrow in the codesnippet above):

Required: PagedList<Comment>?
Found: LiveData<PagedList<Comment>>

For the sake of completeness, this is the getCommentsOfPost() interface:

fun getCommentsOfPost(postId: Long) : LiveData<PagedList<Comment>>

How can I change it so that this error disappears ?

Answer 1

You should return to PagedList, sample:

fun getCommentsOfPost(postId: Long) : PagedList<Comment> {
   // your code
   // return PagedList<Comment>
}