第154篇 Solidity 中众筹的实现

Posted 2023-02-20 wonderBlock

 1.众筹 ERC20

• 用户创建活动；
• 用户可以承诺，将他们的 ERC20 转移到活动中；
• 活动结束后，如果承诺的总金额超过活动目标，活动创建者可以申请提取 ERC20；
• 否则，活动并没有达到目标，用户可以撤回承诺。

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.13;

interface IERC20 
    function transfer(address, uint) external returns (bool);
    function transferFrom(address, address, uint) external returns (bool);


contract CrowdFund 
    event Launch(uint id, address indexed creator, uint goal, uint32 startAt, uint32 endAt);
    event Cancel(uint id);
    event Pledge(uint indexed id, address indexed caller, uint amount);
    event Unpledge(uint indexed id, address indexed caller, uint amount);
    event Claim(uint id);
    event Refund(uint id, address indexed caller, uint amount);

    struct Campaign 
        // Creator of campaign
        address creator;
        // Amount of tokens to raise
        uint goal;
        // Total amount pledged
        uin