AIDL Client

Finally, we can create a Rust client for our new service.


use com_example_birthdayservice::aidl::com::example::birthdayservice::IBirthdayService::IBirthdayService;
use com_example_birthdayservice::binder;

const SERVICE_IDENTIFIER: &str = "birthdayservice";

/// Call the birthday service.
fn main() -> Result<(), Box<dyn Error>> {
    let name = std::env::args().nth(1).unwrap_or_else(|| String::from("Bob"));
    let years = std::env::args()
        .and_then(|arg| arg.parse::<i32>().ok())

    let service = binder::get_interface::<dyn IBirthdayService>(SERVICE_IDENTIFIER)
        .map_err(|_| "Failed to connect to BirthdayService")?;

    // Call the service.
    let msg = service.wishHappyBirthday(&name, years)?;


rust_binary {
    name: "birthday_client",
    crate_name: "birthday_client",
    srcs: ["src/"],
    rustlibs: [
    prefer_rlib: true, // To avoid dynamic link error.

Notice that the client does not depend on libbirthdayservice.

Build, push, and run the client on your device:

m birthday_client
adb push "$ANDROID_PRODUCT_OUT/system/bin/birthday_client" /data/local/tmp
adb shell /data/local/tmp/birthday_client Charlie 60
Happy Birthday Charlie, congratulations with the 60 years!
  • Strong<dyn IBirthdayService> is the trait object representing the service that the client has connected to.
    • Strong is a custom smart pointer type for Binder. It handles both an in-process ref count for the service trait object, and the global Binder ref count that tracks how many processes have a reference to the object.
    • Note that the trait object that the client uses to talk to the service uses the exact same trait that the server implements. For a given Binder interface, there is a single Rust trait generated that both client and server use.
  • Use the same service identifier used when registering the service. This should ideally be defined in a common crate that both the client and server can depend on.