如何将 NFT 转移到另一个智能合约？

我正在尝试建立一个托管合同，该合同将存款作为 NFT 存入合同。我正在努力将 NFT 存入合约。

我从一个简单的 NFT 开始，该 NFT 被铸造到带有 id 的地址。

contract MyEpicNFT is ERC721URIStorage {
  // Magic given to us by OpenZeppelin to help us keep track of tokenIds.
  using Counters for Counters.Counter;
  Counters.Counter private _tokenIds;

  // We need to pass the name of our NFTs token and its symbol.
  constructor() ERC721 ("SquareNFT", "SQUARE") {
    console.log("This is my NFT contract. Woah!");
    console.log(address(this));
  }

  // A function our user will hit to get their NFT.
  function makeNft() public {
    uint256 newItemId = _tokenIds.current();

    _safeMint(msg.sender, newItemId);

    _setTokenURI(newItemId, "https://jsonkeeper.com/b/1LHH");
    console.log("An NFT w/ ID %s has been minted to %s", newItemId, msg.sender);


    _tokenIds.increment();
  }
}

在这种情况下，已将 ID 为 0 的 NFT 铸造到合约的 msg.sender：0xdD870fA1b7C4700F2BD7f44238821C26f7392148

我现在知道我需要批准 Escrow 合约才能被允许“使用”这个代币。为了在 MyEpicNft 合约上执行此操作，我使用 MyEpicNft 的合约地址和铸造的 NFT 的 ID 调用批准函数。

console.log:
 This is my NFT contract. Woah!
 0x5fc7Dc95b4Bb48dbC9894fCaE417482cb8A6A45a

在我的情况下，我使用 (0x5fc7Dc95b4Bb48dbC9894fCaE417482cb8A6A45a, 0) 调用批准 - 这似乎有效。现在我需要在 NftEscrow 合约中做的是存入 NFT。

我正在使用的批准功能来自 ERC721 库

approve(address to, uint256 tokenId)

有一个 depositNFT 函数接受 NFT 地址 - 在我们的例子中是 0x5fc7Dc95b4Bb48dbC9894fCaE417482cb8A6A45a 和 0。但是当我这样做时，我收到错误消息：

The transaction has been reverted to the initial state.
Reason provided by the contract: "ERC721: transfer caller is not owner nor approved".
Debug the transaction to get more information.


contract NftEscrow is IERC721Receiver {
    
    enum ProjectState {newEscrow, nftDeposited, cancelNFT, ethDeposited, canceledBeforeDelivery, deliveryInitiated, delivered}
    
    address payable public sellerAddress;
    address payable public buyerAddress;
    address public nftAddress;
    uint256 tokenID;
    bool buyerCancel = false;
    bool sellerCancel = false;
    ProjectState public projectState;

    receive() external payable {
    
     }

    constructor(){
        sellerAddress = payable(msg.sender);
        projectState = ProjectState.newEscrow;
    }
    
    function onERC721Received( address , address , uint256 , bytes calldata  ) public pure override returns (bytes4) {
        return this.onERC721Received.selector;
    }
    
    function depositNFT(address _NFTAddress, uint256 _TokenID) public onlySeller {
        nftAddress = _NFTAddress;
        tokenID = _TokenID;
        ERC721(nftAddress).safeTransferFrom(msg.sender, address(this), tokenID);
        projectState = ProjectState.nftDeposited;
    }

    function depositEth() public payable {
        buyerAddress = payable(msg.sender);
        projectState = ProjectState.ethDeposited;
    }

    function confirmDelivery()public payable  {
        ERC721(nftAddress).safeTransferFrom(address(this), buyerAddress, tokenID);
        sellerAddress.transfer(address(this).balance);
    }
    

    modifier onlySeller() {
        require(msg.sender == sellerAddress);
        _;
    }

} 
 

不知道我做错了什么并且被困了一天。为什么我不能将 NFT 存入智能合约？