不能用openzeppelin提取令牌

Question

我没有问题地部署令牌和众包，众包合同是基于openzeppelin PostDeliveryCrowdsale的。

克劳德赛：

contract PorrolhoTokenCrowdsale is PostDeliveryCrowdsale {

    constructor(uint256 _openingTime, uint256 _closingTime, uint256 _rate, address _wallet, uint256 _goal, ERC20 _token) public
    Crowdsale(_rate, _wallet, _token)
    TimedCrowdsale(_openingTime, _closingTime)
    {

    }

}

PostDeliveryCrowdsale：

contract PostDeliveryCrowdsale is TimedCrowdsale {
  using SafeMath for uint256;

  mapping(address => uint256) public balances;

  /**
   * @dev Withdraw tokens only after crowdsale ends.
   */
  function withdrawTokens() public {
    require(hasClosed());
    uint256 amount = balances[msg.sender];
    require(amount > 0);
    balances[msg.sender] = 0;
    _deliverTokens(msg.sender, amount);
  }

  /**
   * @dev Overrides parent by storing balances instead of issuing tokens right away.
   * @param _beneficiary Token purchaser
   * @param _tokenAmount Amount of tokens purchased
   */
  function _processPurchase(
    address _beneficiary,
    uint256 _tokenAmount
  )
    internal
  {
    balances[_beneficiary] = balances[_beneficiary].add(_tokenAmount);
  }

}

我可以购买令牌，但是当我调用withdrawTokens()函数时，它会抛出一个错误。众销售合同的余额映射返回我已经购买的令牌金额。

任何想法都会感激的！

Answer 1

我发现问题了！我必须将令牌合同的余额(令牌)转移到众包合同中。好吧，我认错了。