How do you bind multiple packages into a single Java AAR file using gomobile?

Question

I'm getting the error message no exported names in the package when trying to run the command gomobile bind -target=android github.com/nknorg/nkn-sdk-go github.com/nknorg/ncp-go.

The goal is to generate a .aar file from the Go libraries nkn-sdk-go and ncp-go so that the .aar file can be imported into an Android project. I was able to generate the .aar files for each library individually by downloading the repos, moving into their root directories, and running the command gomobile bind -target=android .. However, when trying to run the command for multiple packages (locally or externally) or from outside of the downloaded library's directory (e.g. gomobile bind -target=android nkn-sdk-go), I get the above error message.

I'm running Go version 1.15.5 with NDK version 21.3.6528147 on Windows 10. Any ideas on what the issue could be?

Answer 1

The issue was caused by not running the command within a directory that had been initialised as a go module. I solved the problem by performing the following steps:

1. Create a directory anywhere outside of the $GOPATH/src directory.

mkdir <my-module>

2. Move into the newly created directory.

cd <my-module>

3. Initialise the directory as a go module.

go mod init <my.module.identifier>

4. Bind the packages to generate the .aar file.

gomobile bind -target=android <github.com/package1> <github.com/package2> ...