Category "smartcontracts"

How to transfer a NFT from one account to another using ERC721?

I'm writing an NFT smart contract using the OpenZeppelin ERC721Full contract. I'm able to mint NFTs, but I want to have a button that enables them to be bought.

Truffle compile

I get this Truffle error when I compile. I have tried adding payable to the addresses but it won't work. This is the error: TypeError: Member "transfer" not fo

not found utils/context.sol when i import from openzepplin

i have copied a contract from openzappline. but when i compile it on remix it gives me the error....that utils/context.sol is not found. here is the import prag

Hardhat – What are the strange calls to my smart contract?

I am using Hardhat hackathon boilerplate and calling my smart contract's (address 1c0, addresses shortened for clarity) function MyContract#addProduct from the

How to test smart contract with cross-contract invoke using truffle?

I have two contract, I write in in one file, named Sum.sol. The sum contract invoke Add contract. I just want to test cross-contract invoking. If I didn't put t

Why do openSea fetching data from IPFS all of a sudden?

This the validation json I got for my nft toke 34 HTTP 200 OK Allow: GET, OPTIONS Content-Type: application/json Vary: Accept { "valid": true, "token_u

How to identify Who holds an NFT for how long?

I am developing an NFT collection using ERC721 token. But I would like to know how a particular nft is held by a particular customer? I am sensing there are two

create two nft collections from one smart contract (erc1155) in OpenSea

I want to list two collections on Opensea but instead of creating two smart contracts for that, I want to create only one (to save gas fees of uploading a contr

Why my ERC721 contract in Opensea can't work normally (Without any code of openzeppelin github)

I want to know how OpenSea system read contract and call functions. So, I try to write a ERC721 contract without import any other code. // SPDX-License-Identifi

How to add royalty fee to NFT collection

I am currently learning about NFTs and I reached the point where I deployed the contract and I can mint and everything going well. The only missing part is roya

PHP web3 ERC20 token function call

I have a Smart Contract that represent ERC20 token. I already deployed the smart contract on Binance Testnet using HardHat. I have a deployed Smart Contract add

'clarinet integrate' quickly fails and nothing is logged to console?

Following https://docs.hiro.so/smart-contracts/devnet I can't get the command clarinet integrate to work. I have installed Docker on my mac and am running versi

Deploying a Smart Contract

If I were to deploy a smart contract for NFT's that I would want to sell which is the best way to do this. And is utilising Injected Web3 on Remix.ethereum.org

Hey Can someone explain something about this Smart contract to me - LP Staking Contract

hey so i was looking through github for a LP staking smart contract and i came across this // SPDX-License-Identifier: MIT pragma solidity 0.7.6; import "@open

Elrond mandos test elrond_wasm_debug::mandos_rs pass however erdpy contract test fail

I'm writing test cases for my NFT smart contract (SC). When I check the state of the SC after creating my NFT I'm expecting to see a variable (next_index_to_min

Uniswap v3 nonfungiblePositionManager.mint revert after createAndInitializePoolIfNecessary

I use the official deploy tool "successfully" to deploy Uniswap v3 to a EVM comparable testnet. After NonfungiblePositionManager.createAndInitializePoolIfNecess

Solidity Error: member balance not found or not visible after argument-dependent lookup in contract

I'm getting this error in Solidity for the following code snippet: member balance not found or not visible after argument-dependent lookup in contract functio

Web3 Cannot get value of a public variable from contract

Solidity code: pragma solidity ^0.5.8; contract remainNew{ address public owner = msg.sender; uint public cubeCount = 0; modifier onlyBy(addr

UseDapp - useCall - How to get return value from Solidity function?

I am still quite new with react and solidity and don't know where to start. I can update a String and want to print it out after I changed it. But I want the St