Solidity

Question

代码看起来正确，在转移前批准令牌，但失败并出现错误：“转移金额超过支出者津贴” 发件人帐户的令牌余额超过要求。

有什么想法吗？合约：https://rinkeby.etherscan.io/address/0x2a855c479b14443489963eef90ad449ecdf40cf5#writeContract

pragma solidity ^0.7.0;  


interface IERC20 {
   function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
   function approve(address spender, uint256 amount) external returns (bool); 
   function transfer(address recipient, uint256 amount) external returns (bool);
} 
 
contract FundTokenContract { 
    address public owner;   
     
    constructor(){ 
        owner = msg.sender;
    }   
    
    modifier OnlyOwner() {
        require(msg.sender == owner, "Only owner can call this function.");
        _;
    } 
    
     function fundToken(address tokenAddress, uint amount ) external {  
        require(amount > 0);  
        IERC20(tokenAddress).approve(address(this), amount); 
        IERC20(tokenAddress).transferFrom(msg.sender ,address(this), amount);  
    }  
      
      
    function withdrawToken(address _tokenAddress, address  _recipient, uint _amount) public  OnlyOwner returns (bool){  
        IERC20(_tokenAddress).transfer(_recipient, _amount);
        return true;
    }  
}

Answer 1

当你的合约执行tokenAddress函数approve()时，approve()函数中的msg.sender是你的合约（不是发起交易的用户）。

这有效地批准“您的合约”（第一个参数 address(this)）花费“您的合约”（msg.sender）资金。

然后它试图transferFrom()用户地址，但没有得到批准。

如果你想让你的合约花费属于另一个用户的代币，他们需要从他们的地址直接执行approve(<yourContract>, <amount>)（而不是通过合约）。

注意：请参阅中的 TLDR，它显示了此要求的用处。

Solidity - 转账金额超过消费者津贴

Solidity - transfer amount exceeds spender allowance

transactions

ethereum

metamask