Is it possible to automatically port over a GUI application from Linux/Windows to Android that was written in Rust?

[Raj2032]

Hey guys,

So I am wondering I am thinking of using conrod GUI library, however I don't think it supports Android.

Is it possible to some how use winit to make it work on Android?

If this is the case, say my GUI application worked successfully on Linux, would it work on winit or am I expecting to have breakages?

Also I wanted to know do I have to keep fiddling around with winit every time I make a change with my conrod application?

[madsmtm]

conrod_winit exist, so that could maybe be used to make it work on Android, though you'll have to ask the conrod developers about that - depends on how whether they use the system rendering primitives, or roll their own.

[rib]

Currently one of the difficulties with writing winit applications that need to run on Android is that it's the only platform that requires you to hook into Resumed and Suspended events to know when you have a valid native window which can be used for rendering, and where you have to re-create a surface for rendering each time the application resumes.

The backend will actually panic if you try to access the native_window while the application is paused which may seem brutal but the OS actually destroys the underlying native window and creates a new one when the app resumes which needs to be handled by applications at a higher level.

This shouldn't necessarily be a big problem to handle but as it is currently then most winit integrations are following some common patterns that tend to just assume that a window can be created at the same time as an event loop and all graphics state can also be immediately initialized, and this will basically lead to a panic on Android.

I've recently been experimenting with an alternative Android glue layer (https://github.com/rib/agdk-rust/tree/main/game-activity) and updated winit backend (https://github.com/rib/winit/tree/agdk-game-activity) where I've then also been making a few test applications that demonstrate running on both Android and desktop here: https://github.com/rib/agdk-rust/tree/main/examples.

This stuff is still work-in-progress though.

Hopefully though it's possible to iterate on some of the integration layers and on winit itself to make it easier to write applications that Just Work across mobile/Android and desktop. E.g. I sent this initial PR for egui today to try and improve Android support there: emilk/egui#1634 and maybe similar changes can be made for conrod_winit too.