5 Kotlin Coroutine Secrets I Wish I Knew Earlier

In this video you'll learn about 5 common mistakes about coroutines that I haven't shared before like that.

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00:00 - Introduction
00:29 - Secret 1
04:01 - Secret 2
08:27 - Secret 3
14:11 - Secret 4
19:15 - Secret 5

[laurent.treguier]

For secret #3, I think another option if you really need to catch general exceptions could be to catch CancellationException in its own, dedicated catch block to rethrow it. Not much different, but I like the clarity of using separate catch blocks for each type of exception that can be caught

[yurowitz]

Ive 7 years of experience in Android app dev, But I never paid any attention to these! Thank you so much!

[jakosss]

Please never ever ever ever copy anything byte by byte. You made the function as inefficient as possible. Copy single byte then do ensureActive and your file is copying like 1000 times slower? Always use buffers so such operations start with 4 kb buffer and measure, experiment. But please, never do byte by byte...

[erTurbo]

For #4, in case of Dagger, you could use qualifier, and inject Dispatcher directly. Or without DI, simply set it to some default value.

[AbdulelahAGR]

I have to go check my app for 2 & 3.
Thank you. I love learning about Coroutines

[DenisKor]

note about 5 example, if you read/write data byte-by-byte it could be very slow...

[olgaderyabina]

When I see hardcoded dispatchers in the code, it's usually a sign that people don't care about testing functionality with coroutines in general 🙂

[RbJ]

Hi Philipp. I would like to tell you how much your videos like this one helped me in the recent past and I'm very grateful to you because of it. Also I'd like to give you something back: for Secret 1 there is actually a Service implementation that has a built in lifecycle and lifecycleScope just like a viewModel has and it's called LifecycleService.

[mr.suryansh]

Hey Philipp,

Thanks for the video! Could you please make a new video on "How to use Room with KMP"? Previously, your video covered only Android and iOS, but I would like to see how this can be done for desktop as well.

Also, it would be great if you could create a full 3-4 hour production ready project based on KMP that runs on Android, iOS, and desktop.

Thanks!

[govindyadav]

You can use isActive in your while loop that will solve the problem isn't it ? 14:44

[FilipAdam-vu]

I agree with everything you've read, colleague

[TheAndreArtus]

On tip 3, you can have the exception handling outside the loop (if you want the behaviour of cancelling the loop) i.e. try { while {} }catch {}. This advice may not be pertinent to every exception, but swallowing general exceptions in a loop is rarely advisable.

[atlas]

I knew about supervisor, it is used also in viewmodelScope

[Alchemist]

I think I've made one mistake relating to secret number 2 (Supervisor Job) in my last project. I have a bug (not a crasher) in the app but it happens rarely.

[Radiokot]

What if in #3 we do not re-throw, but replace while (true) with while (isActive)?

[TechCocoon]

Fifth solution is not a solution,
But new problem

[bijithbiju]

Hi please help me i want to do work in kotlin not jetpack. I want to do data transfer using local only hotspot is that possible

[smallbig]

Facts about Kotlin that annoy me:
- They added null safety. But removed exceptions safety.
- They could have built a cancellation mechanism into the generated code. But they invented CancellationException.

[PhpXp]

Secret 5 is going to destroy the performance though ...

[meshoraouf]

Wow can I use it in multiplatform kmp or not?