Engine

Extensions

Extensions are Java or Kotlin code compiled to one DEX file and injected into the target app by a patch. Use them when the patched app needs new code at runtime: Activities, Services, settings UIs, or logic too large to splice inline.

Project layout

Each extension is a Gradle subproject under apps/<app>/extensions/<name>/, or shared/<name>/ for code reused across apps. Its build.gradle.kts:

extra["dexOutputName"] = "<app>-<name>.dex"
apply(from = rootDir.resolve("android-extension-module.gradle.kts"))

dependencies {
    add("compileOnly", project(":shared-<name>"))
}

dexOutputName: the filename of the produced DEX. Keep it stable; patches reference it by name.
dexExcludeClasses: optional comma-separated list of .class files to exclude from the DEX (for build stubs that must not ship).
Dependencies on shared modules are compileOnly. Each extension is emitted as its own DEX, so a non-compileOnly dependency would duplicate classes into multiple DEX files.

Referencing from a patch

A patch declares which DEX files to inject from inside its body:

extendWith("example-downloader.dex")

Multiple calls or multiple arguments are allowed. Filenames must match the dexOutputName from the extension modules.

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