External methods

:::info Third-party packages can be converted automatically; only use the feature in this page when the automation is unwanted. :::

For methods that are not defined in the rust_input folders in the current crate, the #[frb(external)] syntax (see example below) is needed to make flutter_rust_bridge aware of the methods.

Example

Suppose we have these in external crates:

pub struct MyExternalStruct {
    ...
}

impl MyExternalStruct {
    pub fn simple_external_method(&self) -> String {
        // ... some long implementations ...
    }
}

Then, we only need to repeat the function signatures in our main crate as follows:

#[frb(external)]
impl MyExternalStruct {
    pub fn simple_external_method(&self) -> String {}
}

Remark: Just leave the function body empty (i.e. {}), no need to put anything there.

This feature is compatible with the mirroring feature as well.