Struggling with coroutines, but is there a better way to use/get the value for a long running call out here before passing it onto another network coroutine with the callback? I've seen others but than i can't seem to use the value with the latest droid coroutine release, like I can't seem make this work Kotlin Coroutines with returning value
private suspend fun launchGeneratePayload(): String? {
return withContext (Dispatchers.Default) {
try {
val payloadString = slowStringGeneration()//Slow
return@withContext payloadString
} catch (e: java.lang.Exception) {
return@withContext null
}
}
}
Where the value is ultimately used
public someFunction(callback: CallBack) {
val params: JSONObject = JSONObject()
params.put("param1", "param1Value")
runBlocking{ //probably should be launch or similar
val payload = launchGeneratePayload()
params.put("param2", payload)
//call network function with params & callback
//networkCall (
}
}
Thanks for any help
edit: I think was actually looking for was just a bit different with
suspend fun launchGeneratePayload(): String? =
withContext(Dispatchers.Default) {
try {
slowStringGeneration() //slow
} catch (e: java.lang.Exception) {
null
}
}
}
Will add as an answer later incase i'm still off on this/else.
You can use launch coroutine builder to start the coroutine:
private var job: Job = Job()
private var scope = CoroutineScope(Dispatchers.Main + job)
fun someFunction(callback: CallBack) {
val params: JSONObject = JSONObject()
params.put("param1", "param1Value")
scope.launch { // launch the coroutine
val payload = generatePayload() // generate String without blocking the main thread
params.put("param2", payload)
//call network function with params & callback
//networkCall (params, callback)
}
}
suspend fun generatePayload(): String? = withContext(Dispatchers.Default) {
try {
slowStringGeneration() //slow
} catch (e: java.lang.Exception) {
null
}
}
Note: you can also make networkCall() as suspend, then you won't need to use callback.
To use Dispatchers.Main in Android add dependency to the app's build.gradle file
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.0.1'