send" and "transfer" are only available for objects of type "address payable", not "address".

Hello,

I am working on an NFT contract and can’t figure how to withdraw the ETH from the contract when all my NFT will be minted.

I used the version 4.4 of the project openzeppelin-contracts

pragma solidity >=0.4.22 <0.9.0;

import "/app/openzeppelin-contracts/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
import "/app/openzeppelin-contracts/contracts/utils/Counters.sol";
import "/app/openzeppelin-contracts/contracts/access/Ownable.sol";
import "/app/openzeppelin-contracts/contracts/utils/math/SafeMath.sol";

contract SimpleContract is Ownable, ERC721Enumerable {

  function withdraw() public onlyOwner {
          uint balance = address(this).balance;
          msg.sender.transfer(balance);
      }
}

Here is the error message:

Error: "send" and "transfer" are only available for objects of type "address payable", not "address".
   --> <stdin>:102:9:
    |
102 |         msg.sender.transfer(balance);
    |    

I got the example from BAYC contract: https://etherscan.io/address/0xbc4ca0eda7647a8ab7c2061c2e118a18a936f13d#code

Do you know a way to implement this ? The only thing I see different is the code separation from ERC721 and ERC721Enumerable.

Thanks,

[Amxx]

Hello @robinportigliatti

Address payable was introduced by solidity 0.6.0, about 2 years ago. This is documented in their changelog (which also include a section “how to update your code”).

I would also point out that using msg.sender.transfer(balance) is also not recommended since 2019: Check out this article to know more.

I would encourage you use Address.sendValue instead (provided by utils/Address.sol)

[Keyur5123]

Hello,guys this is my structure and function defintion am getting same error in my machine please help me out to solve this…

struct Image { uint id; string hash; string description; uint tipAmount; address payable author; }

images[1] = Image(imageCount, _imgHash, _description, 0, msg.sender);

am not able to use msg.sender