如何在 Flutter 中使用 dart:ffi？

如何解决如何在 Flutter 中使用 dart:ffi？

我一直在思考如何在 Flutter 中实现 dart::ffi，特别是 hello_world example。

从基本的 flutter create 项目（以及一个已经编译的 hello_world.dll）开始尝试：

void main() {
  final dylib = ffi.DynamicLibrary.open('hello_world.dll');
  final HelloWorld hello = dylib
      .lookup<ffi.NativeFunction<hello_world_func>>('hello_world')
      .asFunction();
  hello();
  runApp(MyApp());
}

导致：

Launching lib\main.dart on sdk gphone x86 arm in debug mode...
package:testing_flutter/main.dart:1
√ Built build\app\outputs\flutter-apk\app-debug.apk.
Connecting to VM Service at ws://127.0.0.1:61913/wRTGFN76kik=/ws
E/flutter (11980): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: Invalid argument(s): Failed to load dynamic library (dlopen failed: library "hello_world.dll" not found)
E/flutter (11980): #0      _open (dart:ffi-patch/ffi_dynamic_library_patch.dart:11:55)
E/flutter (11980): #1      new DynamicLibrary.open (dart:ffi-patch/ffi_dynamic_library_patch.dart:20:12)
E/flutter (11980): #2      main
package:testing_flutter/main.dart:8
E/flutter (11980): #3      _runMainZoned.<anonymous closure>.<anonymous closure> (dart:ui/hooks.dart:140:25)
E/flutter (11980): #4      _rootRun (dart:async/zone.dart:1354:13)
E/flutter (11980): #5      _CustomZone.run (dart:async/zone.dart:1258:19)
E/flutter (11980): #6      _runZoned (dart:async/zone.dart:1788:10)
E/flutter (11980): #7      runZonedGuarded (dart:async/zone.dart:1776:12)
E/flutter (11980): #8      _runMainZoned.<anonymous closure> (dart:ui/hooks.dart:133:5)
E/flutter (11980): #9      _delayEntrypointInvocation.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:283:19)
E/flutter (11980): #10     _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:184:12)
E/flutter (11980):

我是否还需要一个 .dylib 版本，例如 in the example？

  var libraryPath =
      path.join(Directory.current.path,'hello_library','libhello.so');
  if (Platform.isMacOS)
    libraryPath =
        path.join(Directory.current.path,'libhello.dylib');
  if (Platform.isWindows)
    libraryPath = path.join(
        Directory.current.path,'Debug','hello.dll');