How model a updatable view for a dynamic form builder and listen to their changes - forms

Question

I'm building a server-driven UI (aka: a form builder) that get the form definition dynamically in JSON, then renders that form.
I need to update the values and send back the results. Some fields also need to trigger validations, so I need to listen to them.
Doing this with JetPack is confusing (to me) because it is not clear how I architect the form builder.
The data for the form builder is:
#Serializable
enum class Action {
Create,
Update,
}
#Serializable
data class ErrorMsg(
val message: String,
val kind: ErrorKind
)
#Serializable
data class Form(
var main_action: Action?,
var title: String?,
var errors: ArrayList<ErrorMsg>
var sections: ArrayList<FormSection>,
)
// A form section is a group of fields
#Serializable
data class FormSection(
var id: UInt,
var fields: ArrayList<FormField>,
var title: String?
)
#Serializable
data class FormField(
val field: String,
val obligatory: Boolean,
val error: ErrorMsg?,
var value: String, //<-- This is what needs to trigger changes!
)
So, if I try to pass the form to a view:
#Composable
fun ComposablePreview() {
val f1 = UIData.FormField.txt("1", "Code", "001")
val f2 = UIData.FormField.pwd("2", "Pwd", "123")
val fields = arrayListOf(f1, f2)
val sections =
UIData.FormSection(
id = 0u, fields = fields, "Sample")
val form_base = UIData.Form(
main_action = null, sections= arrayListOf(sections))
val form by remember { mutableStateOf(form_base) }
FormView(form = form)
}
How get the changes propagated?
I build each form control alike
#Composable
fun TextCtrlView(
field: UIData.FormField,
) {
var value by remember { mutableStateOf(field.value) }
TextField(
label = { Text(field.label) },
value = value,
isError = field.error != null,
onValueChange = { value = it },
)
}