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import "@openzeppelin/contracts/token/ERC721/ERC721.sol";

定义

非同质化代币（也称为契约）的标准接口。

每个符合 ERC-721 的合约都必须实现ERC721和ERC165接口

  • 它更大的想象空间在于将物理世界的资产映射到区块链上。

  • 谜恋猫是第一个实现了ERC721 标准的去中心化应用

  • ERC20代币是可置换的，且可细分为N份（1 = 10 * 0.1）, 而ERC721的Token最小的单位为1，无法再分割。

如果同一个集合的两个物品具有不同的特征，这两个物品是非同质的，而同质是某个部分或数量可以被另一个同等部分或数量所代替。

钱包接口

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/// @dev Note: the ERC-165 identifier for this interface is 0x150b7a02.
interface ERC721TokenReceiver {
    /// @notice Handle the receipt of an NFT
    /// @dev The ERC721 smart contract calls this function on the recipient
    ///  after a `transfer`. This function MAY throw to revert and reject the
    ///  transfer. Return of other than the magic value MUST result in the
    ///  transaction being reverted.
    ///  Note: the contract address is always the message sender.
    /// @param _operator The address which called `safeTransferFrom` function
    /// @param _from The address which previously owned the token
    /// @param _tokenId The NFT identifier which is being transferred
    /// @param _data Additional data with no specified format
    /// @return `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`
    ///  unless throwing
    function onERC721Received(address _operator, address _from, uint256 _tokenId, bytes _data) external returns(bytes4);

参考：https://learnblockchain.cn/article/33

实战

基于OpenZeppelin的ERC721智能合约MyERC721Token

参考https://learnblockchain.cn/article/14779