StellarKit Android

StellarKit is a lightweight and modular client for interacting with the Stellar blockchain, written in Kotlin for Android applications. It's implemented and used by Unstoppable Wallet, a multi-currency crypto wallet.

Features

• Supports sending and receiving XLM and Stellar-based assets
• Handles account creation
• Support for mainnet/testnet networks
• Transaction building and signing
• Account balance and transaction history retrieval

Requirements

• Android 8.0 (API level 26) or higher
• Kotlin 2.0.0+
• Java 8+

Installation

Add the JitPack to module build.gradle

repositories {
    maven { url 'https://jitpack.io' }
}

Add the following to your build.gradle:

dependencies {
    implementation 'com.github.horizontalsystems:stellar-kit-android:<version>'
}

<version> - is the first 7 symbols of a commit hash

Usage

Create an instance of StellarKit using the static method getInstance. It requires the following parameters:

• stellarWallet: an instance of StellarWallet, which can be one of:
  • WatchOnly(addressStr: String) — watch-only wallet with account address
  • Seed(seed: ByteArray) — wallet created from a seed byte array
  • SecretKey(secretSeed: String) — wallet created from a secret seed string
  • Hardware(publicKey: ByteArray) — hardware wallet with public key only (requires external signer)
• network: specify the network with the enum Network which supports:
  • MainNet
  • TestNet
• context: Android Context object
• walletId: a unique string identifier for the wallet instance, useful to distinguish multiple StellarKit instances for different accounts

val stellarWallet = StellarWallet.Seed(bip39Seed)
// val stellarWallet = StellarWallet.SecretKey(secretSeed)
// val stellarWallet = StellarWallet.WatchOnly(accountAddress)
// For hardware/external wallet, use the new getInstance:
// val signer = MyHardwareSigner()
// val stellarKit = StellarKit.getInstance(hardwarePublicKey, signer, Network.MainNet, context, "walletId")

// Example of a custom Signer implementation for hardware wallet
class MyHardwareSigner : Signer {
    override suspend fun sign(data: ByteArray): ByteArray {
        // Call your hardware device here
        return myHardwareSignFunction(data)
    }
}

// val signer = MyHardwareSigner()

val stellarKit = StellarKit.getInstance(stellarWallet, Network.MainNet, context, "walletId")
// For hardware wallet:
// val stellarKit = StellarKit.getInstance(stellarWallet, Network.MainNet, context, "walletId", signer = signer)

You can generate a BIP39 seed using a library like hd-wallet-kit-android

val bip39Seed = Mnemonic().toSeed(words, passphrase)

Synchronization

The instance should be started to sync balances and operations. It also listens for updates. To do so you need to use the following methods:

// to start syncing process and to listen for updates
stellarKit.start()

// Observe syncing state
stellarKit.syncStateFlow.collect { syncState ->
    println("Sync State: $syncStateFlow")
}

// Observe syncing state of operations
stellarKit.operationsSyncStateFlow.collect { syncState ->
    println("Operations Sync State: $syncStateFlow")
}

// Refresh manually
stellarKit.refresh()

// You can stop the syncing process and updates listener by method stop
stellarKit.stop()

Receive Address

// Get receive address
stellarKit.receiveAddress

Sending Payments

// Send native asset
stellarKit.sendNative("recipient_account_id", BigDecimal("10.0"), "optional memo")

// If the recipient account does not exist you can create it
stellarKit.createAccount("new_account_id", BigDecimal("1.0"), "Welcome!")

// Send custom asset
stellarKit.sendAsset("ASSET_CODE:ISSUER_ACCOUNT_ID", "recipient_account_id", BigDecimal("5.0"), "optional memo")

Asset Management

// Enable a custom asset
stellarKit.enableAsset("ASSET_CODE:ISSUER_ACCOUNT_ID", "optional memo")

// Check if asset is enabled
val isEnabled = stellarKit.isAssetEnabled(StellarAsset.Asset("ASSET_CODE", "ISSUER_ACCOUNT_ID"))

Observing Balances and Updates

// Observe balance changes for native asset
stellarKit.getBalanceFlow(StellarAsset.Native).collect { balance ->
    println("Native balance updated: $balance")
}

Example Project

All features of the library are used in the example project located in the app folder. It can be referred to as a starting point for using the library.

License

The StellarKit is open source and available under the terms of the MIT License