Hi guys, can someone explain what is behind of the `delay`? I want to know because when a launch a ...

# coroutines

[SrSouza]

Hi guys, can someone explain what is behind of the delay?

I want to know because when a launch a new job in Dispatchers.Main and use Thread.sleep, the codes blocks, and its okay, this make sense, but, how delay doesn't block when I use it in the Dispatchers.Main? He create a new single thread pool and waits three and use suspendCoroutine and resume after that?

[Dominaezzz]

iirc, Dispatchers.Main has support for delays without having to create a new thread pool. It basically depends on where you use delay.

[Dominaezzz]

So in the case of android, I'm guessing Handler.postDelayed is used.

[SrSouza]

Now I see, this is why when a use delay and the screen goes off (deep sleep) the code after "never" runs

[Dominaezzz]

Wake locks to the rescue.

[louiscad]

Or AlarmManager depending on your use case

[Adam Powell]

Or WorkManager. There are startlingly few reasons for using AlarmManager in 2019.

[louiscad]

Needing exact time is one good reason, right?

[Adam Powell]

The use cases for needing an exact time are very slim, basically if you are an alarm clock or related reminder app. The only AlarmManager APIs that actually grant exact time wakeup anymore are the ones that show pending alarm iconography in the status bar and system UI

[Adam Powell]

All others fuzz and coalesce alarms sent to apps because it scales badly for system and network health otherwise

[SrSouza]

Tkx everyone for the help, I pick AlarmManager because the application that I am working on is embeded.

But the AlarmManager is kinda hard to work and use it just for a throttling is kinda annoying.
I build a lib using suspendCoroutine that's delay using AlarmManager: https://github.com/DevSrSouza/coroutines-alarm-delay#coroutines-alarm-delay

[louiscad]

You could use suspendCancellableCoroutine and cancel the pending intent in the finally block.