Hi guys, What is the recommended way to use Kotlin interface delegation in Android classes? I use a...

# android-architecture

[BMG]

Hi guys,

What is the recommended way to use Kotlin interface delegation in Android classes?
I use a Fragment and want to "delegate" some portion of logic in that fragment to separate class. This way, I can use Kotlin interface delegation to reduce code in main fragment. Basically,

class SomeFragment(viewManager: SomeViewManager) : SomeViewInterface by viewManager {

}

Now I want to pass a View to SomeViewManager class. What is the best way to do it? Should I have a setter in SomeViewManger?

[Ianmedeiros]

It’s not possible to do that with classes that are managed by the framework: i.e. fragments / dialogfragments / activities / etc.

[Ianmedeiros]

What you can do is to remove the fragment logic to another class and compose it instead.

[Ianmedeiros]

And the fragment is the one that build this class. Fragments / Activities are composition roots to your classes

[ghedeon]

maybe with a FragmentFactory tho..

[Ianmedeiros]

Only API 28+

[ghedeon]

aren't you talking about AppComponentFactory ? FragmentFactory is from androidx and I can't see any restrictions.

[BMG]

@ghedeon @Ianmedeiros
Thanks for the points! I didn't know about FragmentFactory! With that, can I inject SomeViewManager and have a setter to set the view once onViewCreated is called?

[ahulyk]

with FragmentFactory you can inject SomeViewManager

[Ianmedeiros]

FragmentFactory only works on devices with API28+

[Ianmedeiros]

are you willing to set your minimum target as api 28 and have no user base?

[Ianmedeiros]

hehe