jnigen 0.1.0 example | Dart package

jnigen examples #

This directory contains examples on how to use jnigen.

Directory	Description
in_app_java	Demonstrates how to include custom Java code in Flutter application and call that using jnigen
pdfbox_plugin	Example of a flutter plugin which provides bindings to Apache PDFBox library. Currently works on Flutter desktop and Dart standalone on linux.
notification_plugin	Example of a reusable Flutter plugin with custom Java code which uses Android libraries.

We intend to cover few more use cases in future.

Currently supported platforms are Linux (Standalone, Flutter), and Android (Flutter).

Create dart package, add jni as dependency and jnigen as dev dependency.
Write the jnigen config similar to the one in pdfbox_plugin.
Generate JNI bindings by running dart run jnigen --config jnigen.yaml.
In the CLI project which uses this package, add this package, and jni as a dependency.
Run dart run jni:setup && dart run jni:setup -p <generated_package_name> to build native libraries for JNI base library and your package respectively.
Import the package. See pdf_info.dart for how to use the JNI from dart standalone.

Flutter FFI plugin has the advantage of bundling the required native libraries along with Android / Linux Desktop app.

To create an FFI plugin with JNI bindings:

Create a plugin using plugin_ffi template.
Remove ffigen-specific files.
Follow the above steps to generate JNI bindings. The plugin can be used from a flutter project.
To use the plugin from Dart projects as well, comment-out or remove flutter SDK requirements from the pubspec.

Create an FFI plugin with Android as the only platform.
Build the example/ Android project using command flutter build apk. After a release build is done, jnigen can use a gradle stub to collect compile classpaths.
Write your custom Java code in android/src/main/java hierarchy of the plugin.
Generate JNI bindings as described above. See notification_plugin/jnigen.yaml for example configuration.