我正在获取DeclarationError :未声明的标识符函数setEndTime(uint _endTime)公共onlyOwner

Question

pragma solidity ^0.5.0;

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/dfbdb11605bab94df6a6b864afc1a068e94a67cc/contracts/crowdsale/Crowdsale.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/dfbdb11605bab94df6a6b864afc1a068e94a67cc/contracts/crowdsale/distribution/FinalizableCrowdsale.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/dfbdb11605bab94df6a6b864afc1a068e94a67cc/contracts/crowdsale/emission/AllowanceCrowdsale.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/dfbdb11605bab94df6a6b864afc1a068e94a67cc/contracts/crowdsale/price/IncreasingPriceCrowdsale.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/dfbdb11605bab94df6a6b864afc1a068e94a67cc/contracts/crowdsale/validation/CappedCrowdsale.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/dfbdb11605bab94df6a6b864afc1a068e94a67cc/contracts/crowdsale/validation/PausableCrowdsale.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/dfbdb11605bab94df6a6b864afc1a068e94a67cc/contracts/crowdsale/validation/TimedCrowdsale.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/dfbdb11605bab94df6a6b864afc1a068e94a67cc/contracts/token/ERC20/IERC20.sol";

/**
 * @title SampleCrowdsale
 * @dev This is an example of a fully fledged crowdsale.
 * The way to add new features to a base crowdsale is by multiple inheritance.
 * In this example we are providing following extensions:
 * CappedCrowdsale - sets a max boundary for raised funds
 * RefundableCrowdsale - set a min goal to be reached and returns funds if it's not met
 * MintedCrowdsale - assumes the token can be minted by the crowdsale, which does so
 * when receiving purchases.
 *
 * After adding multiple features it's good practice to run integration tests
 * to ensure that subcontracts works together as intended.
 */
contract CresstCrowdsale is CappedCrowdsale,TimedCrowdsale,Pausable,IncreasingPriceCrowdsale,AllowanceCrowdsale,FinalizableCrowdsale {
    uint constant TOKEN_DECIMALS = 18;
    uint8 constant TOKEN_DECIMALS_UINT8 = 18;
    uint constant TOKEN_DECIMAL_MULTIPLIER = 10 ** TOKEN_DECIMALS;
    
    constructor (
        uint256 openingTime,   // opening time in unix epoch seconds
        uint256 closingTime,        // closing time in unix epoch seconds
        uint256 rate,               // rate, in TKNbits
        address payable wallet,     //the wallet address that will receive the donation
        address payable tokenWallet,  // the crowd sale wallet address
        uint256 initialRate,            //the rate it will start to increase its always greater
        uint256 finalRate,              //the rate it will end when crowd sale stops always  smaller
        uint256 cap,            // total amount for the Crowdsale, in wei
        IERC20 token            // the token contract address
    ) 
    Crowdsale(rate,wallet,token) 
    CappedCrowdsale(cap)
    TimedCrowdsale(openingTime, closingTime)
    IncreasingPriceCrowdsale(initialRate,finalRate)
    AllowanceCrowdsale(tokenWallet)
    FinalizableCrowdsale()
    
    public {
        
        
    }
    
    
    /**
     * @dev Admin can move end time.
     * @param _endTime New end time.
     */
     function setEndTime(uint _endTime) public onlyOwner notFinalized {
        require(_endTime > openingTime);
        closingTime = uint32(_endTime);
    }


     function setStartTime(uint _startTime) public onlyOwner notFinalized {
        require(_startTime < closingTime);
        openingTime = uint32(_startTime);
    }

    function setHardCap(uint _hardCapTokens) public onlyOwner notFinalized {
        require(_hardCapTokens * TOKEN_DECIMAL_MULTIPLIER > cap);
        cap = _hardCapTokens * TOKEN_DECIMAL_MULTIPLIER;
    }
    
     function setNewRate(uint _NewRate) public onlyOwner notFinalized {
        rate = _NewRate;
    }
    
       
}

在这里，我试图添加一些函数，这些函数可以用来修改startdate、enddate、cap和rate，但这给我带来了严重的错误。如果删除这四个函数，代码就可以了，但是我需要这四个函数(setEndTime、setStartTime、setHardCap、setNewRate)。拜托，我该怎么办？

Answer 1

为了使用onlyOwner修饰符，合同应继承Ownable。

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/release-v2.5.0/contracts/ownership/Ownable.sol";

contract CresstCrowdsale is ..., Ownable {

    function setEndTime(uint _endTime) public onlyOwner notFinalized {
        require(_endTime > openingTime);
        closingTime = uint32(_endTime);
    }
}