Question

使用智能合同时,

DeclarationError: Undeclared identifier. --> @openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol:35:9: | 35 | _requireOwned(tokenId); | ^^^^^^^^^^^^^

智能合同代码:

//SPDX-License-Identifier: Unlicense
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/utils/Counters.sol";
import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";

contract RealEstate is ERC721URIStorage {
    using Counters for Counters.Counter;
    Counters.Counter private _tokenIds;

    constructor() ERC721("Real Estate", "REAL") {}

    function mint(string memory tokenURI) public returns (uint256) {
        _tokenIds.increment();

        uint256 newItemId = _tokenIds.current();
        _mint(msg.sender, newItemId);
        _setTokenURI(newItemId, tokenURI);

        return newItemId;
    }

    function totalSupply() public view returns (uint256) {
        return _tokenIds.current();
    }
}

我试图删除 ERC 721 URIStorage. sol 的自备文件( tokenId), 但仍有错误。

任何帮助都将不胜感激。

我试图删除 ERC 721 URIStorage. sol 的自备文件( tokenId), 但仍有错误。

并试图在我的智能合同中添加自备( etkenId), 但它也犯了同样的错误。

Answer 1

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import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC721/extensions/ERC721URIStorage.sol";

友情链接