When using suspend functions inside composables a common error is the following:
Suspend function should be called only from a coroutine or another suspend function
You can reproduce this error with a code like this:
suspend fun getData(): String {
delay(1000L)
return "Data"
}
@Composable
fun Screen() {
val data = getData() // Suspend function 'getData' should be called...
Text(data)
}
So, you need to call getData() inside the launch function of a coroutine. You can use rememberCoroutineScope for this
@Composable
fun Screen() {
val scope = rememberCoroutineScope()
scope.launch { // Calls to launch should happen inside a LaunchedEffect and not composition
val data = getData()
}
Text(data)
}
Now you will get the error Calls to launch should happen inside a LaunchedEffect and not composition, so let use the LaunchedEffect function
@Composable
fun Screen() {
val scope = rememberCoroutineScope()
LaunchedEffect(scope) {
val data = getData()
}
Text(data)
}Finally, you can save the variable data as a State variable in order that the screen recompose when data changes its value
@Preview
@Composable
fun Screen() {
val scope = rememberCoroutineScope()
val data = remember { mutableStateOf("")}
LaunchedEffect(scope) {
data.value = getData()
}
Text(data.value)
}
