Using return inside a lambda?

Question

In the code below, I want to show my empty views if trips is empty and then return and avoid running the below code, but the compiler says "return is not allowed here".

mainRepo.fetchUpcomingTrips { trips ->     if (trips.isEmpty()) {         showEmptyViews()         return     }      // run some code if it's not empty } 

Is there a way to return like that?

I know I can just put it in an if else block but I hate writing if else's, it's less understandable/readable in my opinion when there's a few more conditions.

Answer 1

Just use the qualified return syntax: return@fetchUpcomingTrips.

In Kotlin, return inside a lambda means return from the innermost nesting fun (ignoring lambdas), and it is not allowed in lambdas that are not inlined.

The return@label syntax is used to specify the scope to return from. You can use the name of the function the lambda is passed to (fetchUpcomingTrips) as the label:

mainRepo.fetchUpcomingTrips { trips ->     if (trips.isEmpty()) {         showEmptyViews()         return@fetchUpcomingTrips      }      // ... } 

Related:

• Return at labels in the language reference

• Whats does “return@” mean?