ERC20
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Let's work with ERC20 tokens with Blueprint!
Back to the map, select the drop down menu of Blueprints > Open Level Blueprint and launch the Level Blueprint Editor
The following screenshot shows Query the name of ERC20 contract and print it on the screen. In this example, we use a Function - Spawn Actor from Class to create an Actor instance from BP_DefiWalletCore Class. The Transformation defines the location, rotation, and scale that will be used by the new Actor. A reference to the new instance is available in the Return Value which feeds as input Value of Function Erc20Name. Erc20Name also has an input Contract Address, for example, we set it as 0xf0307093f23311FE6776a7742dB619EB3df62969. Finally, print the token name with Function - Print String.
Click Compile > Play, USDC is printed in the game.
We can create a variable contract and set the default value as 0xf0307093f23311FE6776a7742dB619EB3df62969 for later easy access.
Similarly, we can call other ERC20 functions by dragging from the Return Value of the SpawnActor BP Defi Wallet Core and search to add Erc20Balance, Erc20Symbol, Erc20Decimals, and Erc20TotalSupply like below
PS: In above example, we use Account Address 0xf0307093f23311FE6776a7742dB619EB3df62969 to query its balance.
All ERC20 functions are members of DefiWalletCoreActor. The Target should be Defi Wallet Core Actor.
Get erc-20 balance
Contract Address: erc20 contract address
Account Address: account address to fetch balance
Balance: get balance of account address
Success: whether succeed or not
Output message: error message, "" if succeed
Get erc-20 name
Contract Address: erc20 contract address
Name: get name
Success: whether succeed or not
Output message: error message, "" if succeed
Get erc-20 symbol
Contract Address: erc20 contract address
Symbol:: get symbol
Success: whether succeed or not
Output message: error message, "" if succeed
Get erc-20 decimals
Contract Address: erc20 contract address
Decimals: get decimals
Success: whether succeed or not
Output message: error message, "" if succeed
Get erc-20 total supply
Contract Address: erc20 contract address
Total Supply: get total supply
Success: whether succeed or not
Output message: error message, "" if succeed
erc20 Moves amount tokens from the caller’s account to to_address.
Contract Address: erc20 contract
Walletindex: wallet index which starts from 0
To Address: to address
Amount: amount
Out: Erc20Transfer callback
erc20 Moves amount tokens from from_address to to_address using the allowance mechanism.
Contract Address: erc20 contract
Walletindex: wallet index which starts from 0
From Address: from address to move
To Address: to address
Amount: amount
Out: Erc20TransferFrom callback
erc20 Allows approved_address to withdraw from your account multiple times, up to the amount amount.
Contract Address: erc20 contract
Walletindex: wallet index which starts from 0
Approved Address: address to approve
Amount: amount
Out: Erc20Approve callback
Returns the amount of tokens in existence
Contract Address: erc20 contract
Erc 20owner: erc20 owner
Erc 20spender: erc20 spender
Result: allowance
Success: whether succeed or not
Output message: error message, "" if succeed
