mutableStateOf

@StateFactoryMarker
public fun <T> mutableStateOf(
    value: T,
    policy: SnapshotMutationPolicy<T> = structuralEqualityPolicy(),
): MutableState<T>

Return a new MutableState initialized with the passed in value

The MutableState class is a single value holder whose reads and writes are observed by Compose. Additionally, writes to it are transacted as part of the Snapshot system.

Parameters

Code Examples

DestructuredStateSample

@Composable
fun DestructuredStateSample() {
    val (count, setCount) = remember { mutableStateOf(0) }
    Text(text = "You clicked $count times")
    Button(onClick = { setCount(count + 1) }) { Text("Click me") }
}

SimpleStateSample

@Composable
fun SimpleStateSample() {
    val count = remember { mutableStateOf(0) }
    Text(text = "You clicked ${count.value} times")
    Button(onClick = { count.value++ }) { Text("Click me") }
}

observeUserSample

@Suppress("unused")
fun observeUserSample() {
    @Composable
    fun observeUser(userId: Int): User? {
        val user = remember(userId) { mutableStateOf<User?>(null) }
        DisposableEffect(userId) {
            val subscription = UserAPI.subscribeToUser(userId) { user.value = it }
            onDispose { subscription.unsubscribe() }
        }
        return user.value
    }
}

stateSample

fun stateSample() {
    @Composable
    fun LoginScreen() {
        var username by remember { mutableStateOf("user") }
        var password by remember { mutableStateOf("pass") }
        fun login() = Api.login(username, password)
        BasicTextField(value = username, onValueChange = { username = it })
        BasicTextField(value = password, onValueChange = { password = it })
        Button(onClick = { login() }) { Text("Login") }
    }
}