Error while calling sendTransaction method -> String' is not a subtype of type 'List<dynamic>' of 'data'

[rahulrmishra]

This is my abi json file

[
  {
    "inputs": [
      {
        "components": [
          {
            "internalType": "address",
            "name": "nftSigner",
            "type": "address"
          }
        ],
        "internalType": "struct TradeLib.FinalizePurchase",
        "name": "data",
        "type": "tuple"
      }
    ],
    "name": "purchase",
    "outputs": [],
    "stateMutability": "nonpayable",
    "type": "function"
  }
  ]

I'm calling a smart contraction method

      Transaction transaction = Transaction.callContract(
        contract: contract,
        function: contract.function('purchase'),
        parameters: [purchaseModel.nftSigner],
        from: EthereumAddress.fromHex(wallet.session.accounts[0]),

      );

 web3client.sendTransaction(
        WalletConnectEthereumCredentials(provider: provider),
        transaction,
        chainId: chainId,
      );

I'm getting error ->

Error type 'String' is not a subtype of type 'List<dynamic>' of 'data'
I/flutter (13485): #0      TupleType.encode (package:web3dart/src/contracts/abi/tuple.dart)
I/flutter (13485): #1      TupleType.encode (package:web3dart/src/contracts/abi/tuple.dart:68:14)
I/flutter (13485): #2      ContractFunction.encodeCall (package:web3dart/src/contracts/abi/abi.dart:255:10)
I/flutter (13485): #3      new Transaction.callContract (package:web3dart/src/core/transaction.dart:29:25)

[MahmoudKEA]

I see you are sending one parameter, while on ABI it asking for two parameters! Check your parameters and make sure your data type is right

[reasje]

@MahmoudKEA Are you sure? Because the ABI is defining only one input and that is of type struct TradeLib.FinalizePurchase which has only one property, I think that is what is causing the problem, Can you guide on how we can encode solidity structs in Flutter side?

[reasje]

@rahulrmishra Try to put the purchaseModel.nftSigner inside another braces : parameters: [[purchaseModel.nftSigner]], First list for parameters, second list for Solidity struct, Looks like Solidity structs are passed as list for encoding, And their properties are the items in this list (Priority should be important).