Class Erc20

java.lang.Object

com.codename1.crypto.evm.Erc20

public final class Erc20
extends Object

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 Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	Erc20.Transfer	A decoded Transfer event.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	TRANSFER_TOPIC	Topic 0 of Transfer(address,address,uint256).

Method Summary

Modifier and Type	Method	Description
static byte[]	allowance(EvmAddress owner, EvmAddress spender)	allowance(owner, spender), for eth_call.
static byte[]	approve(EvmAddress spender, UInt256 amount)	approve(spender, amount).
static byte[]	balanceOf(EvmAddress owner)	balanceOf(owner), for eth_call.
static byte[]	decimals()	decimals(), for eth_call.
static String	decodeString(byte[] returned)	Reads a string returned by name or symbol.
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.
static UInt256	decodeUint(byte[] returned)	Reads a uint256 returned by balanceOf, allowance, decimals or totalSupply.
static byte[]	name()	name(), for eth_call.
static byte[]	symbol()	symbol(), for eth_call.
static byte[]	totalSupply()	totalSupply(), for eth_call.
static byte[]	transfer(EvmAddress to, UInt256 amount)	transfer(to, amount).
static byte[]	transferFrom(EvmAddress from, EvmAddress to, UInt256 amount)	transferFrom(from, to, amount).

Methods inherited from class Object

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

Field Details

TRANSFER_TOPIC

public static final String TRANSFER_TOPIC

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

See Also:

• Constant Field Values

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: the log's topics as 0x hex, as eth_getLogs returns them

• data: the log's data