Web3.0的测试题

任务：在前端开发一个查询UI，查询当前用户账户的ETH余额和指定ERC20合约中的余额

目标：

UI框架指定使用 MUI (https://mui.com)
需要查询到当前账户的ETH余额并展示在UI界面上
需要输入ERC20合约地址后，查询到到当前账户在此ERC20合约中的余额，并展示在UI界面上

提示：

需要安装 Metamask 插件
链接到 Sepolia 网络
ERC20 合约地址 0x7939C9b7cE8BFFc6cb791eCB129f4c385e05727a

时间要求：24小时内给出相应网页，可以部署到github或其他托管平台，也可以通过腾讯会议运行demo代码演示

参考资料

https://web3camp.us/
https://github.com/web3camp-labs

实现：

首先，确保安装了MUI库和Web3.js库：

npm install @mui/material @emotion/react @emotion/styled web3

你可以创建一个JavaScript文件，并编写如下代码：

import React, { useState } from "react";
import Web3 from "web3";
import { Container, TextField, Button, Typography } from "@mui/material";// 创建Web3实例连接到以太坊网络
const web3 = new Web3(window.ethereum);// 定义要查询的ERC20合约地址
// const erc20ContractAddress = "0x7939C9b7cE8BFFc6cb791eCB129f4c385e05727a";export default function Web3View() {const [ethBalance, setEthBalance] = useState(null);const [erc20Balance, setERC20Balance] = useState(null);const [erc20Address, setERC20Address] = useState("");// 检查是否有提供者可用if (typeof window.ethereum !== "undefined") {// 使用以太坊提供者进行初始化web3.setProvider(window.ethereum);} else {console.error("无可用的以太坊提供者");}// 查询当前用户账户的ETH余额async function handleGetEthBalance() {try {// 获取当前用户的账户地址const accounts = await web3.eth.requestAccounts();const account = accounts[0];// 使用web3.eth.getBalance方法查询ETH余额const balanceWei = await web3.eth.getBalance(account);// 将余额从Wei转换为ETH单位const balanceEth = web3.utils.fromWei(balanceWei, "ether");setEthBalance(balanceEth);} catch (error) {console.error("获取ETH余额失败:", error);}}// 查询指定ERC20合约中的余额async function handleGetERC20Balance() {try {// 获取当前用户的账户地址const accounts = await web3.eth.requestAccounts();const account = accounts[0];// 加载ERC20合约的ABI（应用二进制接口）const erc20ABI = [// 方法1：获取代币总供应量{constant: true,inputs: [],name: "totalSupply",outputs: [{name: "",type: "uint256",},],payable: false,stateMutability: "view",type: "function",},// 方法2：获取指定地址的代币余额{constant: true,inputs: [{name: "_owner",type: "address",},],name: "balanceOf",outputs: [{name: "balance",type: "uint256",},],payable: false,stateMutability: "view",type: "function",},// 方法3：转账代币到指定地址{constant: false,inputs: [{name: "_to",type: "address",},{name: "_value",type: "uint256",},],name: "transfer",outputs: [{name: "",type: "bool",},],payable: false,stateMutability: "nonpayable",type: "function",},]; // ERC20合约的ABI定义// 创建ERC20合约实例const erc20Contract = new web3.eth.Contract(erc20ABI, erc20Address);// 使用合约实例的balanceOf方法查询余额const balance = await erc20Contract.methods.balanceOf(account).call();setERC20Balance(balance.toString());} catch (error) {console.error("获取ERC20合约余额失败:", error);}}return (<Container maxWidth="sm"><Typography variant="h4" align="center" gutterBottom>查询账户余额</Typography><Button variant="contained" onClick={handleGetEthBalance}>查询ETH余额</Button>{ethBalance && (<Typography variant="body1" gutterBottom>当前ETH余额：{ethBalance} ETH</Typography>)}<TextFieldlabel="ERC20合约地址"value={erc20Address}onChange={(e) => setERC20Address(e.target.value)}fullWidthmargin="normal"/><Button variant="contained" onClick={handleGetERC20Balance}>查询ERC20余额</Button>{erc20Balance !== null && (<Typography variant="body1" gutterBottom>当前ERC20余额：{erc20Balance}</Typography>)}</Container>);
}