Module android 

Available on Android only.

Android: hand the crate the host’s JavaVM and a Context.

Every read goes through the Java framework, so the crate needs the process’s JavaVM and a Context. A host built on android-activity registers both with ndk-context, which the crate reads without further setup, and so does tao from 0.36 (Tauri 2.12): it registers the application Context in the Activity’s onCreate, before any app code runs. tao before 0.36 registers neither; such a host calls init once, before the first read or ProxyWatcher. Before then, in a host that registered nothing, a read returns Error::Io after the panic hook reports ndk-context’s panic, and a build with panic = "abort" aborts the process there.

tao keeps both for each Activity it creates, and main_android_context hands them out, so a Tauri app makes the call in setup, with no Kotlin of its own. On tao 0.36 and later the call is redundant and harmless; init wins, and it keeps the same application Context:

tauri::Builder::default().setup(|_app| {
    #[cfg(target_os = "android")]
    if let Some(ctx) = tauri::tao::platform::android::prelude::main_android_context() {
        // SAFETY: tao holds a global reference to the Activity while it exists.
        unsafe { proxy_watch::android::init(ctx.java_vm, ctx.context_jobject) }?;
    }
    Ok(())
})

Elsewhere, JNI_OnLoad receives the JavaVM but no Context, so the call usually sits in a JNI function the app’s Kotlin or Java side calls with one, which reaches the JavaVM through its JNIEnv.

Functions

init^⚠

Hands the crate the process’s JavaVM and a Context, from which it keeps the application Context for the life of the process.