参考 OpenZeppelin文档 并结合自己的理解

一种用来检测合约所继承接口的标准方法。EIP-165 中提出。

EIP-165 中的动机：

For some "standard interfaces" like the ERC-20 token interface, it is sometimes useful to query whether a contract supports the interface and if yes, which version of the interface, in order to adapt the way in which the contract is to be interacted with. Specifically for ERC-20, a version identifier has already been proposed. This proposal standardizes the concept of interfaces and standardizes the identification (naming) of interfaces.

继承了 ERC165 的合约方便他人快速检测其实现了哪些接口。

需实现以下函数：

function supportsInterface(interfaceId)

import "@openzeppelin/contracts/utils/introspection/IERC165.sol";

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

interface IERC165 {
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

如果合约实现了 interfaceId 定义的接口，则返回 true

import "@openzeppelin/contracts/utils/introspection/ERC165.sol";

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

import "./IERC165.sol";

abstract contract ERC165 is IERC165 {
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}

表达式 type(x) 可以检测参数 x 的类型信息。

接口类型的特别属性：

type(I).interfaceId :

• 返回接口 I 的 bytes4 类型的接口 ID，接口 ID 被定义为 XOR (异或) 接口内所有函数的函数选择器(function selector)。

ERC721合约中对ERC165的重写：

function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
    return
        interfaceId == type(IERC721).interfaceId ||
        interfaceId == type(IERC721Metadata).interfaceId ||
        super.supportsInterface(interfaceId);
}

参考 OpenZeppelin文档 并结合自己的理解

一种用来检测合约所继承接口的标准方法。EIP-165 中提出。

EIP-165 中的动机：

For some "standard interfaces" like the ERC-20 token interface, it is sometimes useful to query whether a contract supports the interface and if yes, which version of the interface, in order to adapt the way in which the contract is to be interacted with. Specifically for ERC-20, a version identifier has already been proposed. This proposal standardizes the concept of interfaces and standardizes the identification (naming) of interfaces.

继承了 ERC165 的合约方便他人快速检测其实现了哪些接口。

需实现以下函数：

function supportsInterface(interfaceId)

import "@openzeppelin/contracts/utils/introspection/IERC165.sol";

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

interface IERC165 {
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

如果合约实现了 interfaceId 定义的接口，则返回 true

import "@openzeppelin/contracts/utils/introspection/ERC165.sol";

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

import "./IERC165.sol";

abstract contract ERC165 is IERC165 {
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}

表达式 type(x) 可以检测参数 x 的类型信息。

接口类型的特别属性：

type(I).interfaceId :

• 返回接口 I 的 bytes4 类型的接口 ID，接口 ID 被定义为 XOR (异或) 接口内所有函数的函数选择器(function selector)。

ERC721合约中对ERC165的重写：

function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
    return
        interfaceId == type(IERC721).interfaceId ||
        interfaceId == type(IERC721Metadata).interfaceId ||
        super.supportsInterface(interfaceId);
}