leehack/flutter_golang_ffi_example

Example for Flutter and Golang binding

native_add

Golang FFI plugin project for Flutter

Getting Started

This project is a starting point for a Flutter FFI plugin, a specialized package that includes native code directly invoked with Dart FFI.

Project structure

This template uses the following structure:

• src: Contains the golang source code with Makefile that compiles the native code library for the various target platforms.

• lib: Contains the Dart code that defines the API of the plugin, and which calls into the native code using dart:ffi.

• platform folders (android, ios, windows, etc.): Contains the build files for building and bundling the native code library with the platform application.

Building and bundling native code

The pubspec.yaml specifies FFI plugins as follows:

  plugin:
    platforms:
      some_platform:
        ffiPlugin: true

This configuration invokes the native build for the various target platforms and bundles the binaries in Flutter applications using these FFI plugins.

This can be combined with dartPluginClass, such as when FFI is used for the implementation of one platform in a federated plugin:

  plugin:
    implements: some_other_plugin
    platforms:
      some_platform:
        dartPluginClass: SomeClass
        ffiPlugin: true

A plugin can have both FFI and method channels:

  plugin:
    platforms:
      some_platform:
        pluginClass: SomeName
        ffiPlugin: true

The native build systems that are invoked by FFI (and method channel) plugins are:

• For Android: Gradle, which invokes the Android NDK for native builds.
  • See the documentation in android/build.gradle.
• For iOS and MacOS: Xcode, via CocoaPods.
  • See the documentation in ios/native_add.podspec.
  • See the documentation in macos/native_add.podspec.
• For Linux and Windows: CMake.
  • See the documentation in linux/CMakeLists.txt.
  • See the documentation in windows/CMakeLists.txt.

Binding to native code

To use the native code, bindings in Dart are needed. To avoid writing these by hand, they are generated from the header file (src/libsum.h) by package:ffigen. Regenerate the bindings by running flutter pub run ffigen --config ffigen.yaml.

Invoking native code

Very short-running native functions can be directly invoked from any isolate. For example, see sum in lib/native_add.dart.

Flutter help

For help getting started with Flutter, view our online documentation, which offers tutorials, samples, guidance on mobile development, and a full API reference.

flutter_golang_ffi_example's Issues

Compilation on macos m1

First of all, thank you very much for the wonderful article.

I downloaded the repository and ran the example on macos and it worked!
The problem was when I tried to rebuild the dylib and from then on the lib was no longer found nor its reference.
Did you compile it in any different way?
I'm trying to cross over from macos with Apple Silicom M1

CC="clang -arch x86_64"
CGO_ENABLED=1
GOARCH=amd64
GOOS=darwin
go build -trimpath -buildmode=c-shared -o libsum.dylib ../src/sum.go

Thank you!