I m showing a list of named gadgets They have a simple Mutab

Question

I m showing a list of named gadgets They have a simple MutableState lt String gt name property I fetch the list of a gadgets from a Repository The names are update able that s why I made them observable So if the name changes my row automagically updates Isn t compose just beautiful Where it s a bit complicated for me is that I want to sort the list by that name If my app was the only one that could change the name then it wouldn t be too bad As a side effect of changing the name I could some trigger a recomposition at the Column level But it s a multi user system So the update to the name field could come asynchronously I don t want the repository to keep track of sorting the gadgets because it s just a keyed map basically Is there an idiomatic way to solve this sort of problem

Pablichjenkov · Answer

Not sure if I properly understand but basically what you need is to consume a hot flow Expose a StateFlow from your State and consume it from the composable

Travis Griggs · Answer

Why do I need to consume a hot flow I don t even know what that is really slightly smiling face I m a little confused honestly and humbly how you can know that s what I need to do if you re stating up front not sure I properly understand But I m trying to have an open mind here

Pablichjenkov · Answer

Look for hot stream vs cold stream or hot flow vs cold flow Is basically the way you work with the pipeline A pipeline is made out of Chain multiple flows Now a cold pipeline is started or start processing once the collector consumer endpoint pull down the events However a hot pipeline is always sending messages down It doesn t care if a consumer is connected or not it starts sending events down as soon as the server or sender endpoint gets started

Pablichjenkov · Answer

That s speaking in a general stream way Down to kotlin coroutine the cold flow processing starts when flow collect is called in a coroutine scope Usually the cold stream is only process by one scope In the case of the hot one there is 2 scopes involved the sender and the listener Even if you cancel the listener scope the producer scope keeps alive sending events

Pablichjenkov · Answer

If you want to learn more look for reactive streams theory or message driven system design or reactive manifesto rules or reactive system design rules There is a whole world around that

Travis Griggs · Answer

This all sounds good and I appreciate you taking the time to explain it in these broad strokes That you re an advocate is pretty clear I think my question can be abstracted as Given an sized Set of observable things with 1 1 ties observable things and consumers There can be a need to additionally observe consume the set of all changes of that type at a single consumer level rather than the individual changes themselves Does the flow stuff help me with that I was rather enjoying the flexibility of just simple MutableStates confused

Pablichjenkov · Answer

I thought that you were listening for message events coming from a socket or some sort of hot source lol And then you wanted that event to reach the composable column with some processing in between That s why I talked about the flow stuff But now I see basically what you talk about is structuring state In such a case I would say it is up to you the way you design it and expose it to the consumer Flows help with event processing because it has an army of operators Compose State is not so you have to do whatever event processing on your own Which sometimes turns out to be simpler