Changing the jetpack compose remember variable from within another function

Question

I am developing an application for android devices, using the jetpack compose library.

Example I created inside a compose function

var taskVeriable = remember {mutableStateOf("Hello World")}

I need to update the value of variable from another compose function. Is there any way to achieve this?

@Composable
fun TestComposeA(){

var taskVeriable = remember {mutableStateOf("Hello World")}

TestComposeB(taskVeriable)

}

@Composable
fun TestComposeB(taskVeriable : String){
taskVeriable = "New Value"
}

I want to know if there is a way to do this.

Roman Y · Accepted Answer · 2022-10-30 16:56:15Z

10

You can pass mutable state and change it value later:

@Composable
fun TestComposeA(){

val taskVeriable = remember {mutableStateOf("Hello World")}

TestComposeB(taskVeriable)

}

@Composable
fun TestComposeB(taskVeriable : MutableState<String>){
taskVeriable.value = "New Value"
}

answered Oct 30, 2022 at 16:56

Roman Y

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Comments

F.G. · Accepted Answer · 2022-10-29 21:40:30Z

8

You can pass a function that changes your state. This might help you:

@Composable
fun CompA() {
    var text by remember { mutableStateOf("") }

    CompB(
        text = text,
        onChange = { newText ->
            text = newText
        }
    )
}

@Composable
fun CompB(
    text: String,
    onChange: (String) -> Unit
) {
    TextField(value = text, onValueChange = { onChange(it) })
}

edited Oct 29, 2022 at 21:40

answered Oct 29, 2022 at 20:08

F.G.

3262 silver badges7 bronze badges

1 Comment

BenjyTec Over a year ago

This is the recommended way of doing this in Jetpack Compose as it follows the unidirectional data flow pattern.

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