我正在尝试使用 Metamask 将彩票合约连接到 React 应用程序，但是当我在合约上调用 manager() 方法时，我得到一个空数组

Question

Account 数组的记录非常好，Metamask 运行正常，Ethereum 使用正常，但每次调用 manager() 时，我都会收到一个空数组，

我正在学习 Stephen Grider 的 Udemy 课程

 // SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.5.0 <0.9.0;

contract Lottery {
    address public manager;
    address payable[] public players;

    constructor(){
       manager = msg.sender;
    }

    function enter() public payable{
        require(msg.value > 0.01 ether);
        players.push(payable(msg.sender));
    }

    function random() private view returns (uint){
        return uint256(
                keccak256(
                    abi.encodePacked(block.difficulty, block.number, players)
                )
            );
    }

    function pickWinner() public restricted {
        uint index = random() % players.length;
        address contractAddress = address(this);
        players[index].transfer(contractAddress.balance);
        players = new address payable[](0);
    }

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

    function getPlayers() public view returns(address payable[] memory){
        return players;
    }
 }

前端 React Web3 启动

import Web3 from "web3";

const web3 = new Web3(window.ethereum);

export default web3;

前端 React 合约创建

import web3 from "./web3";

const contractAddress = "0x0C04a9a1587524dA1F2c65561Ca157f582242FC8";

const abi = [
  {
    inputs: [],
    stateMutability: "nonpayable",
    type: "constructor",
    constant: undefined,
    payable: undefined,
    signature: "constructor",
  },
  {
    inputs: [],
    name: "enter",
    outputs: [],
    stateMutability: "payable",
    type: "function",
    constant: undefined,
    payable: true,
    signature: "0xe97dcb62",
  },
  {
    inputs: [],
    name: "getPlayers",
    outputs: [[Object]],
    stateMutability: "view",
    type: "function",
    constant: true,
    payable: undefined,
    signature: "0x8b5b9ccc",
  },
  {
    inputs: [],
    name: "manager",
    outputs: [[Object]],
    stateMutability: "view",
    type: "function",
    constant: true,
    payable: undefined,
    signature: "0x481c6a75",
  },
  {
    inputs: [],
    name: "pickWinner",
    outputs: [],
    stateMutability: "nonpayable",
    type: "function",
    constant: undefined,
    payable: undefined,
    signature: "0x5d495aea",
  },
  {
    inputs: [[Object]],
    name: "players",
    outputs: [[Object]],
    stateMutability: "view",
    type: "function",
    constant: true,
    payable: undefined,
    signature: "0xf71d96cb",
  },
];

const lottery = new web3.eth.Contract(abi, contractAddress);

export default lottery;

在 App.js 中调用合约方法：

import React, { useEffect, useRef, useState } from "react";
import web3 from "./web3";
import lottery from "./lottery";
const { ethereum } = window;

function App() {
  useEffect(() => {
    //Calling Manager
    async function getManager() {
      const account = await ethereum.request({ method: "eth_requestAccounts" });
      console.log(account);

      const manager = await lottery.methods.manager().call({
        from: account[0],
      });
      console.log(manager);
    }

    getManager();
  }, []);

  return (
    <div>
      <h2>Lottery Contract</h2>
      <p>This Contract is managed by</p>
    </div>
  );
}

export default App;

Answer 1

我运行您的代码并遇到了这个问题：

constructor(){
       manager = msg.sender;
    }

msg.sender 应付款。据我所知，你不需要明确声明它是应付的，但因为在enter 函数中你有这一行：

players.push(payable(msg.sender));

在类型严格的语言中，类型应该匹配。我运行你的solidity代码并得到这个错误：

如果您将构造函数更改为此：

 constructor (){
        manager = payable(msg.sender);
    }

现在可以了

Answer 2

我是刚接触 Solidity 并做出反应的新手，所以我不能 100% 确定。但似乎manager 是地址类型的变量而不是数组。既然你只是在反应中调用它，它不会是：

const manager = await lottery.methods.manager().call();

由于您只是调用/获取经理地址，我认为不需要设置/发送任何值。

Answer 3

从混音中复制 abi，​​而不是从控制台。