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Let's say I have a class like `class Event(val actionId:Int, arg1:String, arg2: Int, arg3:MyClass, ...
# android
a
Let's say I have a class like 
class Event(val actionId:Int, arg1:String, arg2: Int, arg3:MyClass, arg4:String)
but when I use the class, most likely I'll need 
Event(actionID, oneOfTheArgs)
l
imo they should be all separate classes with a common interface maybe a generic class? 
class Event<T> (val actionId:Int, val arg:T)
for more arguments 
class Event<T1, T2> (val actionId:Int, val arg1:T1, val arg2:T2)
etc...
a
Very interesting, thank you very much
I also wonder if it wouldn't be simpler to have 
class Event(actionId, bundle)
and put in bundle whatever I may need
l
bundles are annoying because you need to keep keys, checking if values exist, etc.
a
yeah, definitely a good point
what about moving all args into another class, so have 
class Event(val actionId:Int, val args:ActionArgs)
l
that works too, though you'd need more boilerplate code when compared to a generic class. Up to you 😉
👍 1
a
I am pretty new to Kotlin. Is this the right syntax 
open class Event<out T>(val action:Int, val arg:T)
?
c
Oh will each event only ever have 1 argument?
a
no, it can have more than one, usually one
c
And do the receivers know which event they expect? Would something like this be acceptable?
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data class User(val userId: Int)
sealed class Event(actionId: Int) {
    data class EventA(val name: String): Event(1)
    data class EventB(val user: User, val someString: String): Event(2)
}
a
Very interesting, learning someting new every day.
In code I'll have someting
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when(actionId){
               id1-> read params and do something
               id2 -> read params and do something
}
c
Yup! Or
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val event:Event = Event.EventA("fas")
when(event) {
    is Event.EventA -> {
        event.name
    }
    is Event.EventB -> {
        event.user.userId
    }
}
a
coming from java, to me it looks like 
Bundle
is the simplest way as it can have any number of params, but as mentioned above by Lukasz, there are keys that I need to remember
c
Yup but it's good to learn other patterns so that you can use plain-old-java or Kotlin without relying on the Android framework for bundles
👍 1
a
Very, very interesting with sealed class, no need to rely on Bundle and also no need to remember keys. Let me give this a shoot
c
Good luck!
a
Thank you very much for your time and valuable info!
Thank you both 👍
❤️ 1
c
Happy to help 🙏
a
@Can Orhan if I have the Event used into another class 
open class Interaction<out T>(...
which is used like 
private val interactions= MutableLiveData<Interaction<Event>>()
then, I can't pass 
Event.EventA
to Interaction as it expects 
Event
type
c
Just created a scratch and the following works for me
Copy code
data class User(val userId: Int)
sealed class Event(actionId: Int) {
    data class EventA(val name: String): Event(1)
    data class EventB(val user: User, val someString: String): Event(2)
}
class Interaction<out T>(val thing: T)

val event:Event = Event.EventA("fas")
val interaction = Interaction<Event>(Event.EventA("Test"))
Are you use your events are extending the base event?
Specifically the colon here: 
data class EventA(val name: String): Event(1)
a
You are right, I did not extend the base event. In case if I don't have any params, I have 
data class EventC():Event(3)
? Isn't this more resource intensive as it uses a empty class?
l
Why wouldn't you use simple 
Event
instead (if actionId is always required)
c
Sealed Class's init is private @Lucas Ł
😢 1
I know 😞
a
yeah, just saw the error
this adds a lot of boilerplate code right? If I have 10 events without args, I need to make 10 classes, while for the other 2-3 events with more params, I have another 3 classes, ending in 13 vs 
class Event(actionId, bundle)
c
I think if it improves the readability of your code, create the parameterless child. Especially if you're going to have multiple zero argument subclasses
a
Am I missing something?
c
10 Events without args are arguably (no pun intended) more readable in code than 
Event(actionId, null)
I'd rather see 
CtaClickEvent()
and 
CloseClickEvent()
instead of 
Event(747)
and 
Event(2112)
👆 2
a
@Can Orhan sorry I had to step out. I agree, however if actionids are in a Enum, we could have 
Event(Actions.TAKE_PICTURE)
so it's more readable. However, I agree, 
Event(actionId, null)
does not look that well. I'll go on this path since it does indeed become very readable and does not depend on bundle.
and really, there should be rarely events without args
Today I learned something because of you. Thank you!
c
No problem. Happy to help 🙂 
Event(Actions.TAKE_PICTURE)
Is certainly readable when creating the event but let's take the scenario where you want act on a list of different events. Suddenly, your simple 
when
statement is going to have a case for Event(Int)` with an if statement over the different `actionId`s
a
I don't understand what you mean with the when
but I like how it turned out
c
Sorry for the delay - What I was saying is that when you're acting on a list of event, you could end up with something like this:
Copy code
data class User(val userId: Int)
sealed class Event(val actionId: Int) {
    data class EventA(val name: String): Event(1)
    data class EventB(val user: User, val someString: String): Event(2)
    class GenericEvent: Event(3)
}
val user = User(3)
val eventsList = listOf(Event.EventA("Foo"), Event.EventB(user, "Bar"))

fun actOnEventUsingWith(event: Event) {
    when(event){
        is Event.EventA -> {
            //Do something
        }
        is Event.EventB -> {
            //Do something else
        }
        is Event.GenericEvent -> {
            if (event.actionId == 4) {
                //Hmmm
            } else if (event.actionId == 5) {
                //Hmmmmmmmm
            }
        }
    }
}
instead of
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fun actOnEventUsingWith(event: Event) {
    when(event){
        is Event.EventA -> {
            //Do something
        }
        is Event.EventB -> {
            //Do something else
        }
        is Event.BoringEvent -> {
            
        }
        is Event.AnotherEvent -> {

        }
    }
}
👍 1
a
Yes, I get it. Thanks
👍 1
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