New solidity learner here. I have created a solidity code to mint NFTs. But I am struggling to create a function that would help me set a fixed price in ether for all listed tokens. Any help or guidance is much appreciated. Attaching the sample code below that I used to deploy NFTS in testnet.opensea.io via IPFS.
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
contract NFT_TOKEN is ERC721Enumerable, Ownable {
using Strings for uint256;
string public baseURI;
string public baseExtension = ".json";
uint256 public cost = 0.01 ether;
uint256 public maxSupply = 10000;
uint256 public maxMintAmount = 20;
bool public paused = false;
constructor(
string memory _name,
string memory _symbol,
string memory _initBaseURI
) ERC721(_name, _symbol) {
setBaseURI(_initBaseURI);
mint(msg.sender, 1);
}
// internal
function _baseURI() internal view virtual override returns (string memory) {
return baseURI;
}
// public
function mint(address _to, uint256 _mintAmount) public payable {
uint256 supply = totalSupply();
require(!paused);
require(_mintAmount > 0);
require(_mintAmount <= maxMintAmount);
require(supply + _mintAmount <= maxSupply);
if(msg.sender != owner()) {
require(msg.value >= cost * _mintAmount);
}
for (uint256 i = 1; i <= _mintAmount; i++) {
_safeMint(_to, supply + i);
}
}
function walletOfOwner(address _owner)
public
view
returns (uint256[] memory)
{
uint256 ownerTokenCount = balanceOf(_owner);
uint256[] memory tokenIds = new uint256[](ownerTokenCount);
for (uint256 i; i < ownerTokenCount; i++) {
tokenIds[i] = tokenOfOwnerByIndex(_owner, i);
}
return tokenIds;
}
function tokenURI(uint256 tokenId)
public
view
virtual
override
returns (string memory)
{
require(
_exists(tokenId),
"ERC721Metadata: URI query for nonexistent token"
);
string memory currentBaseURI = _baseURI();
return
bytes(currentBaseURI).length > 0
? string(abi.encodePacked(baseURI, tokenId.toString(), baseExtension))
: "";
}
// only owner
function setCost(uint256 _newCost) public onlyOwner() {
cost = _newCost;
}
function setmaxMintAmount(uint256 _newmaxMintAmount) public onlyOwner() {
maxMintAmount = _newmaxMintAmount;
}
function setBaseURI(string memory _newBaseURI) public onlyOwner() {
baseURI = _newBaseURI;
}
function setBaseExtension(string memory _newBaseExtension) public onlyOwner() {
baseExtension = _newBaseExtension;
}
function pause(bool _state) public onlyOwner() {
paused = _state;
}
function withdraw() public payable onlyOwner() {
require(payable(msg.sender).send(address(this).balance));
}
}
Best Answer
With this
mint
function you are already set up to receive payments for your NFTs. To enforce payments when someone calls your mint function, add a requirement for transaction value to equal cost per NFT x number of NFTs being minted.Since there is no way to update your
cost
this is a fixed payment.