bee-lite-java

This repository wraps bee-lite functionality and provides its core functionalities to implement Android applications what are able to use Swarm network. Due to type restriction this implemenentation also acts as an adapter to convert bridge between go and java by using the supported types.

Development for Android platform

Please check the same section in this README.md it all applies here as well.

Type restrictions

Go-to-Android (gomobile) Type Mapping Reference

The following table outlines how Go types are mapped to Java/Kotlin when using gomobile bind.

Go Type	Java/Android Equivalent	Category
bool	boolean	Basic Type
string	String	Basic Type
int, int32	int	Numeric
int64	long	Numeric
float32	float	Numeric
float64	double	Numeric
uint8 (byte)	byte	Numeric
[]byte	byte[]	Buffer
error	java.lang.Exception	Error Handling
func	interface (Callback)	Functional
struct	class (with getters/setters)	Object
interface	interface	Object

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⚠️ Handling Unsupported Types

If your Go code uses types not listed above (like uint64 or []string), use the following workarounds:

1. Unsigned 64-bit Integers (uint64)

Java does not support unsigned 64-bit integers.

• Go Side: Cast to int64 before returning.
• Android Side: Use Long.toUnsignedString(value) to display or Long.compareUnsigned(...) to compare.

2. String Slices ([]string)

gomobile does not support slices.

• Workaround A (Wrapper): Create a struct with Get(i int) string and Length() int methods.
• Workaround B (JSON): Serialize the slice to a JSON string in Go and parse it in Android.
• Workaround C (Join): Use strings.Join(slice, "|") in Go and string.split("\\|") in Kotlin/Java.

3. Maps and Complex Structs

For nested data or maps, it is recommended to use JSON serialization to pass data across the bridge.

Compile with gomobile for Android

Target android api 21 is a nice sweet spot because it is Android Version: 5.0 (Lollipop) which is widely supported.

First you need gomobile and bind

make install

then

make build

OR if you want to do it your own

go install golang.org/x/mobile/cmd/gomobile@latest
go get golang.org/x/mobile/bind

In the root of this project run gomobile init

Run the following:

gomobile bind -target=android -androidapi=21 -o mobile.aar