Can I Add Custom Kotlin Code to src-tauri/gen/android and Call it from Rust?

[AbassHammed]

Can i add custom kotlin code to the generated src-tauri/gen/android folder ? if yes, is there an example of how this is done and how the code can be called rust side ?

[FabianLars]

the cleaner approach would be to create a plugin for this as the communication apis are designed for that.

i do remember that someone said they did what you're asking for but i don't know how and can't seem to find it.

[AbassHammed]

Thanks for the fast reply.

the cleaner approach would be to create a plugin for this as the communication apis are designed for that.

That was my thought as well.

i do remember that someone said they did what you're asking for but i don't know how and can't seem to find it.

I’ve searched through the discussions and issues too, but couldn’t find anything.

What I’m trying to achieve is a method (on the Kotlin side) that takes a URI and returns a fd for that content, similar to what the open function in the fs plugin does. However, I need this functionality on the Rust side, since the contents of the file are processed there.

So I’m not sure if it’s possible to call the underlying logic of the open function from the fs plugin directly from Rust, or if I should just proceed with implementing a custom plugin.

[FabianLars]

(just in case) if you need exactly the fs plugin's behavior then you can use https://docs.rs/tauri-plugin-fs/latest/tauri_plugin_fs/struct.Fs.html#method.open

if you don't want the plugin's rust logic but the plain kotlin response then we're already at a tricky situation that we also talked about on discord the last few weeks with other community members. in theory we're so close already with this https://github.com/tauri-apps/plugins-workspace/blob/v2/plugins/fs/src/mobile.rs#L79-L85 but there currently isn't a way to get a PluginHandle for some existing plugin.

[AbassHammed]

(just in case) if you need exactly the fs plugin's behavior then you can use https://docs.rs/tauri-plugin-fs/latest/tauri_plugin_fs/struct.Fs.html#method.open

Yes, the behaviour of the fs plugin maybe exactly what i need, particularly how it handles Android content uri's correctly.

I started implementing it, but i hit a bit of a wall ( definitely a skill issue on my part ). The tauri_plugin_fs::Fs struct doesn't seem to implement Default or expose a new method, and the open function is an instance method, so i'm not sure how to actually get an instance of Fs to call it from.

[FabianLars]

you have to get the Fs instance from Tauri. Minimal example:

use tauri_plugin_fs::FsExt;

#[cfg_attr(mobile, tauri::mobile_entry_point)]
pub fn run() {
  tauri::Builder::default()
      .plugin(tauri_plugin_fs::init())
      .setup(|app| {
          let fs = app.fs();
          let file = fs.open(...);

          Ok(())
       })
       .run(tauri::generate_context!())
       .expect("error while running tauri application");
}