hello, Jan!

how can I help you today?

Hi, Mark, Do you know anything about Network Service Discovery? About 90% of the time I get no discovery at all using it. I'm not trying to do any registration of service - just discovery and resolution.

I happen to be using it for a project for my primary client right now

it is fairly frustrating, though I have a higher success rate than 10%

are you using NsdManager?

Yes I use NsdManager.

one problem with NSD is that it relies on multicast, and so you may run into problems purely based on the network

some home WiFi routers refuse to route multicast packets, for example

onDiscoveryStarted gets started but then nothing else every gets called. No onServiceFound. I tried it on Apple phone and discovery worked great. I tried to break it and couldn't. So I don't think it's global to my router/network.

I agree, that sounds more specific to Android

Sometimes it'll work but no pattern to that. So it worked twice in about 50 attempts today. One thing I noticed is that sometimes it thinks the discovery listener is still active when the app crashed. But I was using a single in Koin for it and changing that to factory hopefully won't have that problem any more.

yeah, NsdManager is very fussy when it comes to having multiple discovery passes going at once

Is there any third party I could try? I downloaded several from github and from play store. They didn't work either. So maybe it is my phone specifically.

we used to use a third-party library, and I eventually tossed it out and wrote something direct to NsdManager

Okay. That's my only topic for today. Thanks.

sorry I didn't have a better answer for you!

hello, Ivano!

Jan: if you come up with another question, let me know!

hello Mark

Ivano: your turn! how can I help you today?

well i do not get if foreground services should be used instead od working manager.the official guide say kinda not

(Jan: BTW, https://play.google.com/store/apps/details?id=c... finds the NSD advertised items on my network)

Ivano: WorkManager is good for short one-off jobs or periodic work

a foreground service is for continuous background operation

yes deferred

so, for example, a music player would use a foreground service, not WorkManager

but you do not run in issues with android modern numbers?

with a foreground service? not really, though there are some limitations on starting one from the background in Android 12 IIRC

ok

i am gonna study more and will come back to you

but I have not seen issues with a foreground service launched from the foreground, such as from user interaction with an activity

thanks i go to sleep will come back. sorry for all the questions in the last period.changing job and

want to learn a lot

I am happy to try to help!

well jan left

would like to ask you what happen if somebody does a call while i am getting a retrofit call or something similar,

"does a call" meaning a voice call?

coroutines and rxjava are not going to help

yes

should i use services for all the use cases then?

if you are worried about losing your network connection, that is not a problem on GSM networks

oh, are you worried about your app moving to the background while the call is in progress?

yesss

ah

really worried

the big variable is how long you are trying to do network I/O while in the background

in theory i should put everything i do under a service?

probably not, but it would depend a lot on your app and what you are trying to do

ok

and last thing

please

i saw a tutorial using lifecycleservice

and i saw that also workmanagers can be combined with lifecycle

via live data

so my question is if i use flow and get ridd of livedata, to be sure are bbound to the cycle, should i take care of coroutine scope?

for activities and fragments, usually you should use a CoroutineScope tied to a lifecycle, or tied to the ViewModel (viewModelScope)

yess

great

was expecting this

ah one other small nouance, i am mastering coroutines but really do not get why the scope can be declared with a plus sign in an instance variable. cannot find sounding explanations Mark

there is a plus() function available for CoroutineScope

plus() is an operator function

inmean +

when you see 1 + 2, the compiler converts that to 1.plus(2)

i mean +

so, anything that has a plus() function implementation can be used with the + operator

no i do not mean that

do you have an example?

please let me tempt your patience finding an example

looking for

i have it but have to log

this plus

it's the same thing, in the end

Dispatchers.Main is a CoroutineContext

CoroutineContext has a plus() function

so, what you have is equivalent to: private val coroutineScope = CoroutineScope(Dispatchers.Main.plus(parentJob))

and why i need to add this parentjob

really do not get

what is wrong with withContext(Main)

it is simply a convenience syntax for combining two CoroutineContext objects

nothing

mmh

it does not specify the parent job, for structured concurrency, but you do not always need that

i have an idea tomorrow will try to run without parent job

and I think withContext() looks up the parent job automatically, but my memory is fuzzy on the details

ok is kind of boiler plate i guess, in modern code i do not see, only in tutorials

thank you

yes, I rarely see that syntax

thank you

really helpful

have a nice evening

you too!

get some sleep! :-)

thanks yes really need, i am dreaming code unfortunately in this period

bye