In what cases and from which parts of the system can a suspend function call be initiated?

Suspend functions in Android (Kotlin) are used to perform asynchronous operations without blocking the main thread. A suspend function can be invoked from:

• Another suspend function — as they can only be called from coroutines or other suspend functions.
• Within a coroutine launched via CoroutineScope, for example, in a ViewModel or Activity.

Example:

fun loadData() {
    CoroutineScope(Dispatchers.Main).launch {
        val data = fetchData() // fetchData is a suspend function
        updateUI(data)
    }
}

suspend fun fetchData(): String {
    delay(1000) // simulate a long operation
    return "Data"
}

Thus, the call to a suspend function is initiated from a coroutine, which can be launched from the component's lifecycle or another suspend function. This allows efficient management of asynchronous tasks and prevents blocking the UI.