Client and backend. This class is shared: the same code is compiled into your app and into your server, so everything on this page works in both.

public final class Erc20

Object
Erc20

Call data for ERC-20 tokens (USDC, USDT, DAI…). A token transfer is a transaction to the token contract with value 0 and this call data; the recipient is inside it.

EvmAddress recipient = EvmAddress.parse("0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed");
EvmAddress usdc = EvmAddress.parse("0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48");
long nonce = 0;
UInt256 tip = UInt256.parseUnits("1", 9);
UInt256 maxFee = UInt256.parseUnits("30", 9);
byte[] data = Erc20.transfer(recipient, UInt256.parseUnits("25", 6));  // 25 USDC
EvmTransaction tx = EvmTransaction.eip1559(1, nonce, tip, maxFee, 65000, usdc, UInt256.ZERO, data);

Nested types

class Erc20.Transfer A decoded Transfer event.

Fields

public static final String TRANSFER_TOPIC = "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef" Topic 0 of Transfer(address,address,uint256).

Methods

`public static byte[] transfer(EvmAddress to, UInt256 amount)`	`transfer(to, amount)`.
`public static byte[] approve(EvmAddress spender, UInt256 amount)`	`approve(spender, amount)`.
`public static byte[] transferFrom(EvmAddress from, EvmAddress to, UInt256 amount)`	`transferFrom(from, to, amount)`.
`public static byte[] balanceOf(EvmAddress owner)`	`balanceOf(owner)`, for `eth_call`.
`public static byte[] allowance(EvmAddress owner, EvmAddress spender)`	`allowance(owner, spender)`, for `eth_call`.
`public static byte[] decimals()`	`decimals()`, for `eth_call`.
`public static byte[] symbol()`	`symbol()`, for `eth_call`.
`public static byte[] name()`	`name()`, for `eth_call`.
`public static byte[] totalSupply()`	`totalSupply()`, for `eth_call`.
`public static` `UInt256 decodeUint(byte[] returned)`	Reads a `uint256` returned by `balanceOf`, `allowance`, `decimals` or `totalSupply`.
`public static` `String decodeString(byte[] returned)`	Reads a `string` returned by `name` or `symbol`.
`public static` `Erc20.Transfer decodeTransfer(List<String> topics, byte[] data)`	Decodes a `Transfer` log from its topics and data, or answers `null` for any other log.

Inherited methods

From Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait, clone, finalize

Field details

TRANSFER_TOPIC

public static final String TRANSFER_TOPIC = "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"

Topic 0 of Transfer(address,address,uint256).

Method details

transfer

public static byte[] transfer(EvmAddress to, UInt256 amount)

transfer(to, amount).

approve

public static byte[] approve(EvmAddress spender, UInt256 amount)

approve(spender, amount).

transferFrom

public static byte[] transferFrom(EvmAddress from, EvmAddress to, UInt256 amount)

transferFrom(from, to, amount).

balanceOf

public static byte[] balanceOf(EvmAddress owner)

balanceOf(owner), for eth_call.

allowance

public static byte[] allowance(EvmAddress owner, EvmAddress spender)

allowance(owner, spender), for eth_call.

decimals

public static byte[] decimals()

decimals(), for eth_call.

symbol

public static byte[] symbol()

symbol(), for eth_call.

name

public static byte[] name()

name(), for eth_call.

totalSupply

public static byte[] totalSupply()

totalSupply(), for eth_call.

decodeUint

public static UInt256 decodeUint(byte[] returned)

Reads a uint256 returned by balanceOf, allowance, decimals or totalSupply.

decodeString

public static String decodeString(byte[] returned)

Reads a string returned by name or symbol.

decodeTransfer

public static Erc20.Transfer decodeTransfer(List<String> topics, byte[] data)

Decodes a Transfer log from its topics and data, or answers null for any other log.

Parameters

topics List<String>: the log’s topics as 0x hex, as eth_getLogs returns them
data byte[]: the log’s data