A new Flutter FFI plugin project.
This project is a starting point for a Flutter FFI plugin, a specialized package that includes native code directly invoked with Dart FFI.
This template uses the following structure:
src: Contains the native source code, and a CmakeFile.txt file for building that source code into a dynamic library.
lib: Contains the Dart code that defines the API of the plugin, and which calls into the native code using
platform folders (
windows, etc.): Contains the build files for building and bundling the native code library with the platform application.
Buidling and bundling native code
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
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
Longer-running functions should be invoked on a helper isolate to avoid
dropping frames in Flutter applications.
For example, see
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