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Android Integration Guide
Wallet Core is available on the Android platform, through Java/JNI bindings. In this guide we show how to use it.
A sample application is available at: https://github.com/trustwallet/wallet-core/tree/master/samples/android .
Prerequisites
- Android Studio
- Android NDK Support plugin
Adding Library Dependency
Android releases are hosted on GitHub packages, please checkout this installation guide, you need to add GitHub access token to install it.
Add this dependency to build.gradle:
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dependencies {
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implementation "com.trustwallet:wallet-core:<latest_tag>"
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}
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Add
maven and credentials (local properties or system environment variables)1
allprojects {
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repositories {
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maven {
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url = uri("https://maven.pkg.github.com/trustwallet/wallet-core")
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credentials {
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username = project.findProperty("gpr.user") as String?: System.getenv("GITHUB_USER")
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password = project.findProperty("gpr.key") as String?: System.getenv("GITHUB_TOKEN")
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}
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}
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}
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}
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Code Examples
In the following sections we show code examples for some common funcions. Please refer to the Wallet Usage Guide for detailed explanations.
Wallet Management
First thing we need is to load JNI library
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init {
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System.loadLibrary("TrustWalletCore")
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}
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Creating or Importing a Multi-Coin HD Wallet
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val wallet = HDWallet(128, "")
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val wallet = HDWallet("ripple scissors kick mammal hire column oak again sun offer wealth tomorrow wagon turn fatal", "")
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Account Address Derivation
Generating the Default Address for a Coin
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val addressBTC = wallet.getAddressForCoin(CoinType.BITCOIN)
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val addressETH = wallet.getAddressForCoin(CoinType.ETHEREUM)
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val addressBNB = wallet.getAddressForCoin(CoinType.BINANCE)
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Generating an Address Using a Custom Derivation Path (Expert)
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val key = wallet.getKey("m/44\'/60\'/1\'/0/0") // m/44'/60'/1'/0/0
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val address = CoinType.ETHEREUM.deriveAddress(key)
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Transaction Signing
In general, when creating a new blockchain transaction, a wallet has to:
- 1.Put together a transaction with relevant fields (source, target, amount, etc.)
- 2.Sign the transaction, using the account private key. This is done by Wallet Core.
- 3.Send to a node for broadcasting to the blockchain network.
Ethereum Transaction Signing
Code example to fill in signer input parameters, perform signing, and retrieve encoded result:
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val signerInput = Ethereum.SigningInput.newBuilder().apply {
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chainId = ByteString.copyFrom(BigInteger("01").toByteArray())
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gasPrice = BigInteger("d693a400", 16).toByteString() // decimal 3600000000
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gasLimit = BigInteger("5208", 16).toByteString() // decimal 21000
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toAddress = dummyReceiverAddress
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transaction = Ethereum.Transaction.newBuilder().apply {
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transfer = Ethereum.Transaction.Transfer.newBuilder().apply {
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amount = BigInteger("0348bca5a16000", 16).toByteString()
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}.build()
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}.build()
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privateKey = ByteString.copyFrom(secretPrivateKey.data())
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}.build()
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val output = AnySigner.sign(signerInput, CoinType.ETHEREUM, Ethereum.SigningOutput.parser())
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println("Signed transaction: \n${signerOutput.encoded.toByteArray().toHexString()}")
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Last modified 3mo ago