Hi ! As a experiment and in order to understand wh...

# compose

[loloof64]

Hi ! As a experiment and in order to understand why a part of my project does not work, I've created this ColorSquare experiment.

1. It is a simple `@Composable`which outputs a Surface with solid background color, and a Button.
2. When the user clicks on the button, the expected behaviour is that the square changes its color.
3. In this experiment, things are a bit more complicated : I'm using a ColorSquareState class, with a method chooseNextColor, and I'm storing a `mutableState`on an instance of this class.
But when the `chooseNextColor`is called, it does not force recomposition. Why ? Is there a simple workaround keeping the use of `ColorSquareState`as long as method chooseNextColor?

ColorSquare_Composable.cpp

[Oleksandr Balan]

The field you update should be backed by State. In your snippet the whole ColorSquareState is wrapped in the State and Compose are subscribed to it’s changes, but you are mutating the property inside ColorSquareState , which is not a State .

So try the following:
1. Declare the property as State :

var bgColor by mutableStateOf(blue)

2. Remove unnecessary mutableStateOf for the whole state:

val color by remember { ColorSquareState() }

[loloof64]

Thank you I'm gonna try now 🙂

[loloof64]

Yes, it works. Thank you very much 🙂