pressing the back button, and then reopening causes hang

[tiby312]

Pressing the android "back" button, and then opening the app again either by icon, or process list, causes the app to hang, or say "app has stopped"

[tomaka]

That is unfortunately a consequence of the bad model of execution of winit.

[tiby312]

Hmm this also happens with the basic example even without using winit.

[tomaka]

Yes, this crate was more or less designed in order to be used directly by winit (or rather glutin at the time). Therefore the design decisions of winit/glutin impacted it in a negative way.

[mb64]

The main problem here is that Android is free to call onDestroy(), followed by onCreate(), without re-loading the library. This leads to main() being called twice, which rust really hates, complaining about e.g. trying to write to stdout after shutdown, along with other things.

I'm currently working on the EventLoop 2.0 Android implementation, and as part of that re-writing a lot of the glue. This includes changes such as a local version of android_native_app_glue, and potential modifications to it open up more possibilities for solving this issue. I have two proposed solutions:

Don't require the thread to die during onDestroy()

This would entail checking if it's alive in onCreate() and acting accordingly.

Pros: main() gets to keep running when possible
Cons: It feels wrong to not destroy things during onDestroy. Also, it can never send the Winit LoopDestroyed event (because it's impossible to know if it'll actually be destroyed)

dlopen() and dlclose() the Rust code during onCreate() and onDestroy()

Essentially resetting the static data between runs of main().

Pros: It seems more consistent to say that onCreate() always calls main(), rather than "it sometimes does, sometimes doesn't."
Cons: Weird dlopen() hackery because it's Android

I'm curious to know which of these people think is best, or if you have other suggestions.

[mb64]

This is fixed by #223, which calls fn main() directly instead of through Rust's startup glue.