presenter fun just takes some number of channels from the vi

Question

presenter fun just takes some number of channels from the view and returns a view model that holds some number of channels the view needs to listen on

dave08 · Answer

You use android architectural components or just a simple presenter How do you manage lifecycle

withoutclass · Answer

so far not using architecture components My view is my activity fragment it handles itself When it pauses I null out my channel references When it resumes it get s a new set of channel s from the presenter fun

dave08 · Answer

Do you have a sample out or maybe a gist I was also thinking along those lines and would be interested in getting more details about your setup

withoutclass · Answer

Sadly no all my code I ve written for it so far has been client code

withoutclass · Answer

withoutclass · Answer

This is the blog that inspired me to give it a go with channels

withoutclass · Answer

I pretty much follow that blog just instead of using RX I use channels

withoutclass · Answer

I am pretty excited about it No dealing with view interfaces no dealing with presenter interfaces Testing the presenters is brain dead easy because the presenter fun takes some number of channels and returns others so you can test fire events down your input channel and verify you get the correct event out of your output channel

withoutclass · Answer

One key difference I did was to use `sealed class` for my events

dave08 · Answer

Very interesting thanks If you have a chance to post a gist of the differences between rx and channel implementation just the idea and main pitfalls it would be great

withoutclass · Answer

yea I am sick today I should write something up xD

dave08 · Answer

Why `sealed class` A click is simply `Unit` etc like RxBinding lib

withoutclass · Answer

What I did was create `sealed class` like OnClick It has sub objects like `object PositiveButton OnClick ` etc So I have a handful of generic events that are easy and readable to pass in a channel and clearly define what type of action occurred

withoutclass · Answer

I think this makes it very clear what s happening in the UI as well as clear for testing When presenter fun receives a `PositiveButton` click event expect presenter channel to return some expected event

dave08 · Answer

I tend to avoid locking presenter logic w platform implementation details I d rather have a `val onSubmitRequest ReceiveChannel lt RegistrationRequest gt `

dave08 · Answer

But I know there s more technical problems I didn t yet figure out like handling closed channels and lifecycle

withoutclass · Answer

Well that s why the events into the presenter are generic Positive button negative button DialogPositiveButton etc The events out of the presenter are more specific to what actually needs to occur which I think is fine considering that s the role of the presenter anyways at least in my view

withoutclass · Answer

One way I could see decoupling more would be to also provide the presenter with an activityReference then the presenter could actually send down code to be executed in the activity fragment or execute it itself I kind of see that as tying the activity to the presenter fun as well just in a different way