简介：

这是一个轻量级的eth库，支持eth的私钥，公钥，地址的生成，和eth及其智能合约的转账离线签名操作

项目地址：https://github.com/wypeng2012/ETHForAndroid

欢迎star

support Android sdk >= 14

- 如何使用

  1. 先添加bip44forandroidlibrary的依赖

implementation ‘party.loveit:bip44forandroidlibrary:1.0.7’

  1. 生成 ETH相关的公钥私钥等

code:

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List<String> words = Bip44Utils.generateMnemonicWords(MainActivity.this);
Log.e("TAG", "words: " + words.toString());

//m / purpose’ / coin_type’ / account’ / change / address_index
BigInteger priKey = Bip44Utils.getPathPrivateKey(words, "m/44'/60'/0'/0/0");

ECKeyPair ecKeyPair = ECKeyPair.create(priKey);

String publicKey = ecKeyPair.getPublicKeyToString();
Log.e("TAG", "publicKey: " + publicKey);

String privateKey = ecKeyPair.getPrivateKeyToString();
Log.e("TAG", "privateKey: " + privateKey);

String address = "0x" + Keys.getAddress(ecKeyPair);
Log.e("TAG", "address: " + address);

result:

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2018-12-06 14:04:54.053 6857-7056/party.loveit.ethforandroid E/TAG: words: [kite, portion, actress, prize, multiply, odor, mobile, social, refuse, fruit, tunnel, smart]
2018-12-06 14:04:54.648 6857-7056/party.loveit.ethforandroid E/TAG: publicKey: 0x7eac8e97e93d250630ff507c4339a4950f9b194d0951ac7b4b260c61521613f77b13dc8621cd0691f711c134ba5693a7460dc5231c98636ce6f727d4e725596a
2018-12-06 14:04:54.648 6857-7056/party.loveit.ethforandroid E/TAG: privateKey: 0xc3f0b16731bc42ae07ff0304ba1172e6414dcd8de7a612e1ec281c109181f3d9
2018-12-06 14:04:54.653 6857-7056/party.loveit.ethforandroid E/TAG: address: 0x4a7484c7c9ed536ef428e48240ad5707b21dc6e8
  1. eth转账离线签名
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/**
 * 离线签名eth
 *
 * @param to//转账的钱包地址
 * @param nonce//获取到的交易次数
 * @param gasPrice
 * @param gasLimit
 * @param value           //转账的值
 * @return
 */
public static String signedEthTransactionData(String privateKey, String to, BigInteger nonce, BigInteger gasPrice, BigInteger gasLimit, String value) throws Exception {
    if (words == null || words.size() != 12) {
        throw new RuntimeException("please generateMnemonic first");
    }
    //把十进制的转换成ETH的Wei, 1ETH = 10^18 Wei
    BigDecimal realValue = Convert.toWei(value, Convert.Unit.ETHER);
    RawTransaction rawTransaction = RawTransaction.createEtherTransaction(nonce, gasPrice, gasLimit, to, realValue.toBigIntegerExact());
    //手续费= (gasPrice * gasLimit ) / 10^18 ether

    Credentials credentials = Credentials.create(privateKey);
    //使用TransactionEncoder对RawTransaction进行签名操作
    byte[] signedMessage = TransactionEncoder.signMessage(rawTransaction, credentials);
    //        //转换成0x开头的字符串
    return Numeric.toHexString(signedMessage);
}
  1. eth智能合约转账离线签名
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/**
     * 离线签名eth
     *
     * @param contractAddress//合约地址
     * @param to//转账的钱包地址
     * @param nonce//获取到的交易次数
     * @param gasPrice
     * @param gasLimit
     * @param value                 //转账的值
     * @return
     */
    public static String signedEthContractTransactionData(String privateKey, String contractAddress, String to, BigInteger nonce, BigInteger gasPrice, BigInteger gasLimit, Double value, Double decimal) throws Exception {
        if (words == null || words.size() != 12) {
            throw new RuntimeException("please generateMnemonic first");
        }
        //因为每个代币可以规定自己的小数位, 所以实际的转账值=数值 * 10^小数位
        BigDecimal realValue = BigDecimal.valueOf(value * Math.pow(10.0, decimal));

        //0xa9059cbb代表某个代币的转账方法hex(transfer) + 对方的转账地址hex + 转账的值的hex
        String data = "0xa9059cbb" + Numeric.toHexStringNoPrefixZeroPadded(Numeric.toBigInt(to), 64) + Numeric.toHexStringNoPrefixZeroPadded(realValue.toBigInteger(), 64);
        RawTransaction rawTransaction = RawTransaction.createTransaction(nonce, gasPrice, gasLimit, contractAddress, data);
        //手续费= (gasPrice * gasLimit ) / 10^18 ether

        Credentials credentials = Credentials.create(privateKey);
        //使用TransactionEncoder对RawTransaction进行签名操作
        byte[] signedMessage = TransactionEncoder.signMessage(rawTransaction, credentials);
        //转换成0x开头的字符串
        return Numeric.toHexString(signedMessage);
    }

- How to dependencies

  1. Maven
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<dependency>
  <groupId>party.loveit</groupId>
  <artifactId>ethforandroidlibrary</artifactId>
  <version>1.0.1</version>
  <type>pom</type>
</dependency>
  1. Gradle
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compile 'party.loveit:ethforandroidlibrary:1.0.1'

or

implementation 'party.loveit:ethforandroidlibrary:1.0.1'
  1. Ivy
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<dependency org='party.loveit' name='ethforandroidlibrary' rev='1.0.1'>
  <artifact name='ethforandroidlibrary' ext='pom' ></artifact>
</dependency>