address.transfer(value)是在实体契约中抛出错误。

Question

我正在Remix建立一个批准合同，并且在这个问题上被困住了。

当我试图使用address.transfer(value)传输魏时，它会抛出一个错误。我已经在下面的代码中标记了它。

也许这个错误与构造函数中声明的struct Request有关，因为当.transfer()失败时，混合调试器就会在那里结束，但是我找不到解释。

pragma solidity ^0.4.17;

 contract Campaign {
     struct Request {
         string description;
         uint32 value;
         address recipient;
         bool complete;
         uint approvalCount;
         mapping(address => bool) approvals;
     }

     Request[] public requests;
     address public manager;
     uint32 public minimumContribution;
    //  tutorial uses 'approvers' not 'contributors'
     mapping(address => bool) public contributors;
     uint32 public contributorCount;

     modifier restricted {
         require(msg.sender == manager );
        _;
     }


     constructor(uint32 minimum) public {
         manager = msg.sender;
         minimumContribution = minimum;
     }

     function contribute() public payable{
         require(msg.value > minimumContribution);

         contributors[msg.sender] = true; // because contributor is 
         contributorCount++;
     }

     function createRequest(string description, uint32 value, address recipient) 
        public restricted {
         Request memory newRequest = Request({
            description: description, 
            value: value, 
            recipient: recipient, 
            complete: false,
            approvalCount: 0
         });

         requests.push(newRequest);
     }

     function approveRequest(uint16 index) public {
         Request storage r = requests[index];

         // make sure the address has contributed, but has not approved this one yet
         require(contributors[msg.sender]); 
         require(!r.approvals[msg.sender]);

         r.approvals[msg.sender] = true;
         r.approvalCount++;
     }

     function finalizeRequest(uint16 index) public restricted {
         Request storage r = requests[index];

         // make sure more than 50% of contributors approved this request
         require(r.approvalCount > (contributorCount / 2));
         //make sure that this request has not been completed before
         require(!r.complete);

         // FAILS ON THIS LINE. Remix debugger goes through this line then ends on line 3 of the contract, in the constructor function. 
         r.recipient.transfer(r.value);


         // mark this request as completed
         r.complete = true;
     }

 }

注意，在.transfer()上失败后，调试器跳转到构造函数，其中创建了struct Request {...}。(这就是问题所在吗？)

我认为它可能是调用.transfer()的函数，所以我试图通过在一个单独的函数中调用它来隔离传输，但是它仍然失败了。

不确定是否有用，但我输入的地址(address.transfer()中的地址)是从javascriptVM中混合创建的备用地址中复制的。

Answer 1

r.value规定的魏氏金额超过了合同中规定的数额。我在合同中增加了一行，以确保合同中有足够的钱：

require(address(this).balance > r.value);