Which way of rendering sealed class hierarchy do you prefer

Question

Edgars · Answer

I prefer the first style but I would extract them into separate methods e g ```when state is Loading gt showLoadingState is Success gt showSuccessState state is Error gt showErrorState state ```

ursus · Answer

I also for some reason like the 1 even thought its more dangerous Any reason why its like that for you arent you biased because its only 3 states Imagine 5 youd need to put same GONE code in 4 and the VISIBLE in 1

Edgars · Answer

I don t see a problem with that in and of itself If two of the states have some similarities e g they both hide some of the same views I d extract that showing or hiding to a separate function and call it from both of the states

Edgars · Answer

I like one because that way whatever needs to happen for a state is written in that function two can have a bug where you override some properties after checking the n th state ``` assume state is Success if state is Success whatever some view isVisible = true else some view isVisible = false if state is Error state is not Error whatever else some view isVisible = false ``` As a result `some view` will be hidden even though we re in the `Success` state and want to show that view

ursus · Answer

Hmm for that example I agree with you but imagine this

ursus · Answer

```fun View renderState1 state when state is Loading gt progressBar visibility = View VISIBLE errorView visibility = View GONE contentView visibility = View GONE whateEverView visibility = View GONE somethingView visibility = View GONE is Success gt progressBar visibility = View GONE errorView visibility = View GONE contentView visibility = View VISIBLE contentView setData state data whateEverView visibility = View GONE somethingView visibility = View GONE is Error gt progressBar visibility = View GONE errorView visibility = View VISIBLE errorView setErrorMessage state errorMessage contentView visibility = View GONE whateEverView visibility = View GONE somethingView visibility = View GONE is Whatever gt progressBar visibility = View GONE errorView visibility = View VISIBLE errorView setErrorMessage state errorMessage contentView visibility = View GONE whateEverView visibility = View VISIBILE somethingView visibility = View GONE is Something gt progressBar visibility = View GONE errorView visibility = View VISIBLE errorView setErrorMessage state errorMessage contentView visibility = View GONE whateEverView visibility = View GONE somethingView visibility = View VISIBLE ```

ursus · Answer

it doesnt scale

ursus · Answer

I might have messed up the values but basically one thing is turned on for one case

Edgars · Answer

First of all I d extract each `when` case to its own function as in the snippet I posted Then if all of the cases work with the same bunch of views you could have something like ```fun showViews content Boolean = false error Boolean = false something Boolean = false content isVisible = content error isVisible = error ``` that you would call like `showViews error = true `

ursus · Answer

that would not be so handy since you will need payloads there as well not only booleans

Edgars · Answer

You would need to mix and match that Use that for showing hiding views and then work with your payloads in each state function ```when state is Success gt showViews content = true update UI content here ``` Personally I wouldn t be too worried about having `someView isVisible = false` in each of the `showFooState ` functions but that s just me

Rodrigo Fonseca · Answer

a good option to complement would be using `viewflipper`

Steve · Answer

I think having a method `showLoadingState ` where you just list off all the views and explicitly set their visibility state among other things isn t bad

Steve · Answer

as long as the visibility state of the views isn t manipulated outside of those functions