在網頁上列出使用者擁有的 ERC721 代幣

假設我有一個代表一組撲克牌的 ERC721 (NFT) 合約。

是否有範常式式碼顯示列出了使用者在網頁上擁有的 ERC721 合約的所有令牌，以便使用者可以選擇一個？

你可以在你的智能合約中添加一個函式來模仿 CryptoKitties 合約在 function 中所做的事情tokensOfOwner，這

返回分配給地址的所有 Kitty ID 的列表

/// @title The facet of the CryptoKitties core contract that manages ownership, ERC-721 (draft) compliant.
/// @author Axiom Zen (https://www.axiomzen.co)
/// @dev Ref: https://github.com/ethereum/EIPs/issues/721
///  See the KittyCore contract documentation to understand how the various contract facets are arranged.
contract KittyOwnership is KittyBase, ERC721 {

[...]

/// @notice Returns a list of all Kitty IDs assigned to an address.
   /// @param _owner The owner whose Kitties we are interested in.
   /// @dev This method MUST NEVER be called by smart contract code. First, it's fairly
   ///  expensive (it walks the entire Kitty array looking for cats belonging to owner),
   ///  but it also returns a dynamic array, which is only supported for web3 calls, and
   ///  not contract-to-contract calls.
   function tokensOfOwner(address _owner) external view returns(uint256[] ownerTokens) {
       uint256 tokenCount = balanceOf(_owner);

       if (tokenCount == 0) {
           // Return an empty array
           return new uint256[](0);
       } else {
           uint256[] memory result = new uint256[](tokenCount);
           uint256 totalCats = totalSupply();
           uint256 resultIndex = 0;

           // We count on the fact that all cats have IDs starting at 1 and increasing
           // sequentially up to the totalCat count.
           uint256 catId;

           for (catId = 1; catId <= totalCats; catId++) {
               if (kittyIndexToOwner[catId] == _owner) {
                   result[resultIndex] = catId;
                   resultIndex++;
               }
           }

           return result;
       }
   }

ERC721 標準的目前草案要求遵守該標準的合約具有totalSupply屬性以及balanceOf(address _owner)功能ownerOf(uint256 _tokenId)。

要查找給定地址擁有的所有項目，前端 DApp 需要查詢totalSupply（例如，52 張撲克牌），然後從零循環到該數字並呼叫該ownerOfID 上的方法，尋找匹配的結果正在搜尋的目標地址。找到匹配項後，可以將該項目添加到該帳戶的已知資產列表中，如果該列表的長度現在等於balanceOf該使用者的呼叫結果，則循環可以停止，因為所有資產都已成立。

ERC721 標準可選地呼叫tokenOfOwnerByIndex(address _owner, uint256 _index)可以使循環更短的呼叫，但這是為 ERC721 令牌實現的可選函式。如果您創建的令牌具有這樣的功能，那麼您可以使用它更有效地循環結果。

引用自：https://ethereum.stackexchange.com/questions/54959