Hello all, I'm stumped trying to get a `Text` object's contents in a `@Composable` to update when a ...

# compose-desktop

[Kebbin]

Hello all,
I'm stumped trying to get a Text object's contents in a @Composable to update when a global String variable changes.
I have a global String var dataIn = "" that regularly fills with characters like data += char in one function, but I can't get its value change to recompose the displayed Text in the other function!
I thought it should be doable using var dataDisplay: String = remember { mutableStateOf(dataIn) } and Text(text = dataDisplay) but it won't update the text display every time a new char is added to the dataIn variable.
Thanks again!

[Michael Paus]

Why should it change? By definition it is only read the first time when dataDisplay is initialised. That’s what remember is made for.

[Kebbin]

This is what I need to get my head around.
I might need to use another command?

[Michael Paus]

You’ll have to explicitly update dataDisplay if you want to change it.

[Michael Paus]

It might be better to introduce some StateFlow in your model which you can then observe in your Composable.

[Kebbin]

Hmm. So once dataIn has been updated by appending a Char, I need to then update the dataDisplay variable somehow?

[Kebbin]

OK! So I need to learn about StateFlow then?

[Kebbin]

Observing external values sounds like what I'm after! If I can control the UI updates within the screen function that holds the Text object, that would be good?

[Zach Klippenstein (he/him) [MOD]]

Why can't you just make your global var a MutableState?

[Zach Klippenstein (he/him) [MOD]]

Better yet, avoid using a global in the first place

[Zach Klippenstein (he/him) [MOD]]

Ah, it looks like you figured out the mutable state thing in another thread.

[Kebbin]

Hey @Zach Klippenstein (he/him) [MOD]!
Thanks very much for your onto and attention mate.
Yes I did eventually twig, and found that I could indeed use that method! 😆
What more can you tell me about avoiding global vars now? Thanks!