Flutter Gomobile test

This is a sample project to test running golang code in a Flutter app, using gomobile.

gomobile builds golang project into native library for mobile platforms. This sample project imports that library and runs it in .dart code.

Project structure

This project mainly consists of the following parts:

• go_sample: Contains go code with simple functions defined.

• ios/Runner: contains Swift code that runs on iOS and communicates with the Dart code.

• lib: Contains the Dart code for mobile app

How to Build for iOS

1. Prepare Go Project

• Prepare your own project, or use the sample code in this sample project.
• In this sample project, the go project is go_sample.

2. Build with gomobile

• In your Go project, run the command below to build the library for iOS:

  gomobile bind -target=ios

3. Copy Generated .xcframework

• Copy the generated .xcframework to the iOS folder in your project.
  • In this sample project, copy it is ios/Samplefunc.xcframework.

4. Write Swift Bridge Code

• Write Swift code to create a bridge for calling the native library.
  • This is typically done by specifying the types for each function argument.
  • In this sample project, the file is located at ios/Runner/SamplefuncBridge.swift.

5. Edit AppDelegate.swift

• Edit ios/Runner/AppDelegate.swift. I add a single line to register the plugin for the Go library.

6. Configure Xcode Project

• Open ios/Runner.xcworkspace with Xcode.
  • Add the Swift bridge code and the .xcframework to your project in Xcode, like the picture below.
  • Once you add them to Xcode, replacing an existing framework with a new version should work fine, as long as the files are not renamed.
  • If the filename has changed, run Xcode again and repeat the steps below.

7. Write Flutter Code

• Write the flutter app you intended
• Use MethodChannel to communicate with Swift from Dart.
  • Refer to the comments in main.dart for more details.
  • It is recommended to keep the code for the MethodChannel in a separate file

8. Run flutter app to test

• After setting up the project in Xcode, you can run the app by simply executing:

   flutter run

• Note: You can run it in the terminal, but the terminal doesn't print information like log.info in the go code. If you used log in the go code, run the flutter app via Xcode

How to build for Android

I got an app build error and stopped working on it for now.

References

• Go wiki: Mobile
• Flutter docs for MethodChannel