How to use delegate property in MutableStateFlow in jetpack compose-CodePudding

I am using MutableStateFlow in my jetpack compose. Like below

val isBluetoothEnabled = MutableStateFlow(false)

whenever I tried to use the value of variable like this .value i.e. isBluetoothEnabled.value. So I am trying to use delegate property to avoid using .value

val isBluetoothEnabled by MutableStateFlow(false)

but I am getting weird error

Type 'MutableStateFlow<TypeVariable(T)>' has no method 'getValue(PairViewModel, KProperty<*>)' and thus it cannot serve as a delegate

CodePudding user response：

You should use this method

import androidx.compose.runtime.Composable
import androidx.compose.runtime.collectAsState
import androidx.lifecycle.ViewModel
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.asStateFlow


class TestViewModel constructor(
    
) : ViewModel() {
    private val _isBluetoothEnabled = MutableStateFlow(false)
    val isBluetoothEnabled = _isBluetoothEnabled.asStateFlow()

}
@Composable
fun Sample1(
    viewModel: TestViewModel 
) {
    val isBluetoothEnabled = viewModel.isBluetoothEnabled.collectAsState()
    
}

CodePudding user response：

If you want to use it as a delegate in your Composable, you'll have to add .collectAsState() to StateFlow, otherwise Compose cannot detect state changes and therefore cannot update the value when necessary :)

Also if you only handle/update this value within the UI (and not a ViewModel for example), simply use mutableStateOf(false)