Use local SDK if the file exist

docs/_developer_onboarding.md

@@ -117,6 +117,10 @@ You can also have access to the aars through the [release](https://github.com/ma
 
 #### Build the SDK locally
 
+Easiest way: run the script [./tools/sdk/build_rust_sdk.sh](./tools/sdk/build_rust_sdk.sh) and just answer the questions.
+
+Legacy way:
+
 If you need to locally build the sdk-android you can use
 the [build](https://github.com/matrix-org/matrix-rust-components-kotlin/blob/main/scripts/build.sh) script.
 
@@ -147,15 +151,6 @@ Troubleshooting:
  - If you get the error `thread 'main' panicked at 'called `Option::unwrap()` on a `None` value', .cargo/registry/src/index.crates.io-6f17d22bba15001f/cargo-ndk-2.11.0/src/cli.rs:345:18` try updating your Cargo NDK version. In this case, 2.11.0 is too old so `cargo install cargo-ndk` to install a newer version.
  - If you get the error `Unsupported class file major version 64` try changing your JVM version. In this case, Java 20 is not supported in Gradle yet, so downgrade to an earlier version (Java 17 worked in this case).
 
-Finally let the `matrix/impl` module use this aar by changing the dependencies from `libs.matrix.sdk` to `projects.libraries.rustsdk`:
-
-```groovy
-dependencies {
-    api(projects.libraries.rustsdk)    // <- use the local version of the sdk. Uncomment this line.
-    //implementation(libs.matrix.sdk)  // <- use the released version. Comment this line.
-}
-```
-
 You are good to test your local rust development now!
 
 ### The Android project

libraries/matrix/impl/build.gradle.kts

@@ -29,8 +29,12 @@ anvil {
 }
 
 dependencies {
-    // implementation(projects.libraries.rustsdk)
-    implementation(libs.matrix.sdk)
+    if (file("${rootDir.path}/libraries/rustsdk/matrix-rust-sdk.aar").exists()) {
+        println("\nNote: Using local binary of the Rust SDK.\n")
+        implementation(projects.libraries.rustsdk)
+    } else {
+        implementation(libs.matrix.sdk)
+    }
     implementation(projects.libraries.di)
     implementation(projects.libraries.androidutils)
     implementation(projects.libraries.network)