how do i make a compose desktop (JVM) app only eve...

# compose-desktop

[Zoff]

how do i make a compose desktop (JVM) app only ever start 1 instance? is there a proper way of doing this?

[S.]

you can bind your instances to a single port or lock via files to check if another instance is already running

[אליהו הדס]

@Zoff You can use my lib https://github.com/kdroidFilter/ComposeNativeTray/?tab=readme-ov-file#-single-instance-management

[אליהו הדס]

@S. Opening a port will trigger the Windows firewall, so you need to use a lockfile. That’s what I do in my library.

[Zoff]

nice. but its seems sadly compose can not do it out of the box? without native compiled code

[Zoff]

can i rip out the parts with a lockfile in your code? would you point me to it?

[S.]

it's here https://github.com/kdroidFilter/ComposeNativeTray/blob/master/src/commonMain/kotlin/com/kdroid/composetray/utils/SingleInstanceManager.kt
you don't need native code for that, it's all jvm

[Zoff]

cool thanks

[Zoff]

just tried your lib, sadly on vanilla debian there is no tray at all in the OS. so any apps with tray just dont work like expected. oh well debian ...

[S.]

@אליהו הדס yeah that's right, locking via files is a bit cleaner. it was easier to implement to handle deep links and only asks for permissions once, so that's fine for now. my ideal solution would still be a native launcher to get rid of the jvm delay for deep links

[אליהו הדס]

@S. You can also display a splash screen.

[S.]

yeah but the problem is that the jvm splash screen shows for every new deep link

[Zoff]

still awesome lib

[אליהו הדס]

@S. Yes, I know, it's problematic. I haven't found a solution for it, and I don't have time to create a native launcher.

[אליהו הדס]

Actually, I think that under Windows, it would be possible to prevent the splash screen image from being read via JNA, and therefore the second instance wouldn't display it because it wouldn't be able to read it.

[אליהו הדס]

That seems much simpler to me, but I think it would only work under Windows.

[אליהו הדס]

@Zoff Does your system support trays? Because vanilla GNOME requires an extension.

[S.]

oh interesting.
macos doesn't have this problem (and I don't publish for linux), it's only windows for me

[אליהו הדס]

Yes, macOS by default only allows one instance

[אליהו הדס]

@S. It's a bit hacky, but I think it will work.

[S.]

there also seems to be a provided solution in the WinRT sdk https://learn.microsoft.com/en-us/windows/windows-app-sdk/api/winrt/microsoft.windows.[…]e.appinstance.findorregisterforkey?view=windows-app-sdk-1.8
but I don't know if and how it's possible to use that

[אליהו הדס]

It also requires a native launcher.

[Zoff]

no my system does not support trays. but your SingleInstanceManager.kt worked like a charm. thanks so much for that

[Zoff]

https://github.com/zoff99/undereat_material/commit/82afb09d129d17bbfdcbd15f7bb8876eab93e0b6

[Zoff]

just used a random UUID as app identifier