A modern programming language that makes developers happier.

kotlinlang

image.png

Hello, I have a global `Coroutines` (img1)to read something(?), when it's not null ,I want send this to a function`@Composable`  for update  variables(`mutableStateOf`) ,How can I achieve? thanks!

You cannot send anything to a composable function, but you can update some state which is used by this composable function, using mutableStateOf or Compose

but  it really depends how this receive() function is used, if it called from Composable function, it would be better to have some kind ViewModel/Repository for it and use it from you composable code

Thanks! I was thinking of something like broadcasting

Yes, usage of StateFlow or mutableStateOf would allow to recompose your UI with new data

Yes,I understand your suggestion,
before:   I think about move `mutableStateOf` var from fun scope to class scope(img1) , crash!;
Now : I tried let the `mutableStateOf` var pointing a other var which in common scope(img2), brilliant!

You shouldn’t wrap it to remember, you can just use state directly if it some shared state

remember is used to remember some object to keep it between compose recompositions

but if you declare mutableStateOf somewhere outside of composable function, no need to worry about missing it, it will just have the same lifecycle as class where it declared (or global if it top-level function)

Could you give a good example?Thanks!
when I remove `remember` ,it's crash:

No, you should always use remember inside of composable

but in this case you will not be able to update it from outside

what I mean is:
```val hardVersion = mutableStateOf("test")

@Composable
fun fragmentBox1() {
    TextField(value  = hardVersion.value)
}

fun receive() {
   GlobalScope.launch {
     hardVersion.value = "something"
   }
}```

<https://kotlinlang.slack.com/archives/C01D6HTPATV/p1645761035089459?thread_ts=1645754743.153129&amp;cid=C01D6HTPATV>

It’s not compiling because you use hardVersion without get()

Sorry,I can't find get() from `MutableState`

Thank you very much, you are very patient!:heart:

Haha, no problem, hope it helpful
Just remember it’s more an example, and for real code I would rather abstract all those state loading and updating to repository/view model

Mean this? Move any var to RuntimeContent such as hardVersion?

If they updated from outside of composable functions, yes, otherwise it's better to keep them internal

FYI, you need `.value` because you use `mutableStateOf` directly instead of as a delegate:

```var x = mutableStateOf("hello")
Text(text = x.value)
x.value = "world"```
vs.
```var x by mutableStateOf("hello")
Text(text = x)
x = "world"```