前端Vue项目调用页面web3.js:连接metaMask钱包,

这里分享下相关文档

1.web3.js中文文档 https://learnblockchain.cn/docs/web3.js/getting-started.html
2.metamask官方文档：https://docs.metamask.io/

第一种方法:连接钱包

// 参考网址:https://blog.csdn.net/cjy_win/article/details/117248919?spm=1001.2101.3001.6650.1&utm_medium=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7ERate-1.pc_relevant_aa&depth_1-utm_source=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7ERate-1.pc_relevant_aa&utm_relevant_index=2

// 1.先确认自己的浏览器安装了metaMask插件,建议谷歌浏览器

// 2.Vue项目安装web3.js,使用npm安装web3js依赖

//在vue中安装web3
npm install web3 --save
//在main.js引入
import Web3 from 'web3'
Vue.prototype.Web3 = Web3

自己创建一个getWeb3.js文件把下面代码放入里面,需要用到的页面直接引入即可

import Web3 from "web3";
const getWeb3 = () =>
  new Promise((resolve, reject) => {
    // Wait for loading completion to avoid race conditions with web3 injection timing.
    window.addEventListener("load", async () => {
      // Modern dapp browsers...
      if (window.ethereum) {
        const web3 = new Web3(window.ethereum);
        try {
          // Request account access if needed
          await window.ethereum.enable();
          // Acccounts now exposed
          resolve(web3);
        } catch (error) {
          reject(error);
        }
      }
      // Legacy dapp browsers...
      else if (window.web3) {
        // Use Mist/MetaMask's provider.
        const web3 = window.web3;
        console.log("Injected web3 detected.");
        resolve(web3);
      }
      // Fallback to localhost; use dev console port by default...
      else {
        const provider = new Web3.providers.HttpProvider(
          "http://127.0.0.1:9545"
        );
        const web3 = new Web3(provider);
        console.log("No web3 instance injected, using Local web3.");
        resolve(web3);
      }
    });
  });
export default {
	getWeb3
};

3.上面是一个js方法,根据当前页面来初始化web3对象,在对应页面 通过  const Web3= require('../common/getWeb3') 引入,然后通过下面方法使用

注意:加web3前面必须有window : window.web3

 Web3.default.getWeb3().then((res) => {
      window.web3 = res;
      console.log("getWeb3", res);
    });

源码：

第二种方法: 连接钱包 安装依赖直接可以使用

参考网址:https://blog.csdn.net/qq_16137795/article/details/120239103?utm_medium=distribute.pc_aggpage_search_result.none-task-blog-2~aggregatepage~first_rank_ecpm_v1~rank_v31_ecpm-1-120239103.pc_agg_new_rank&utm_term=web3+%E8%B0%83%E7%94%A8MetaMask%E9%92%B1%E5%8C%85%E8%BD%AC%E8%B4%A6eth&spm=1000.2123.3001.4430

// 1.先确认自己的浏览器安装了metaMask插件,建议谷歌浏览器

// 2.Vue项目安装web3.js,使用npm安装web3js依赖

//在vue中安装web3
npm install web3 --save
//在main.js引入
import Web3 from 'web3'
Vue.prototype.Web3 = Web3


注意:ethereum 和 web3 前必须有window:  window.ethereum window.web3

 if (window.ethereum) {
        window.ethereum.enable().then((res) => {
          alert("当前钱包地址:" + res[0]);
        });
      } else {
        alert("请安装MetaMask钱包");
      }

源码：

其他功能:

1、在 mounted 中自动检测浏览器是否安装MetaMask钱包

 mounted () {
    if (window.ethereum) {
      window.ethereum.enable().then((res) => {
        //alert("当前钱包地址："+res[0])
      })
    }else{
      alert("请安装MetaMask钱包")
    }
  }

2、查询钱包ETH余额

let web3 = new Web3(window.web3.currentProvider)
let fromAddress = web3.eth.accounts[0];
web3.eth.getBalance(fromAddress,(err, res) => {
   if (!err) {
       console.log("ETH余额==",res.toNumber()/Math.pow(10,18));
   }
 })

3、查询代币余额

let web3 = new Web3(window.web3.currentProvider)
let fromAddress = web3.eth.accounts[0];
let ethContract = web3.eth.contract("代币合约Abi")
let functionInstance = ethContract.at("代币合约地址")
functionInstance.balanceOf(fromAddress,(err, res) => {
   if (!err) {
       //代币精度根据所发行的代币合约精度换算 
       console.log("代币余额==",res.toNumber()/Math.pow(10,18));
   }
})

4、ETH转账

let web3 = new Web3(window.web3.currentProvider)
let fromAddress = web3.eth.accounts[0];
//转账数量
let amount = 1*Math.pow(10,18);
//收款地址
let toAddress = "0x40141cF4756A72DF8D8f81c1E0c2ad403C127b9E";
web3.eth.sendTransaction({
    gas: 21000,
    gasPrice: 5000000000,
    from: fromAddress,
    to: toAddress,
    value: amount
 }, (err, result) => {
     console.log("转账Hash=",result)
 })

5、代币转账

let web3 = new Web3(window.web3.currentProvider)
let ethContract = web3.eth.contract("代币Abi")
let functionInstance = ethContract.at("代币地址")
//当前钱包地址
let fromAddress = web3.eth.accounts[0];
//转账数量
let amount = 100*Math.pow(10,18);
//接收地址
let toAddress = "0x40141cF4756A72DF8D8f81c1E0c2ad403C127b9E";
functionInstance.transfer(toAddress,amount,{
     gas: 21000,
     gasPrice: 5000000000,
     from: fromAddress
 }, (err, result) => {
       console.log("转账Hash:",result)
  })

6、代币授权

let web3 = new Web3(window.web3.currentProvider)
let abiContract = web3.eth.contract("代币合约Abi")
let contractInstance = abiContract.at("代币合约地址")
//当前钱包地址
var fromAddress = web3.eth.accounts[0];
//授权数量
var amount = 1000 * Math.pow(10,18);
contractInstance.approve("授权地址",amount,{
    gas: 80000,
    gasPrice: 1500000000,
    from: fromAddress
}, (err, result) => {
    console.log("交易Hash：",result)
})

7、查询授权数量

let web3 = new Web3(window.web3.currentProvider)
let abiContract = web3.eth.contract("代币合约Abi")
let contractInstance = abiContract.at("代币合约地址")
contractInstance.allowance("授权的用户钱包地址","授权的地址",(err, res) => {
    if (!err) {
        console.log("授权数量==",res.toNumber());
    }
})

8、查询去中心化交易所LP地址数量 计算价格

let web3 = new Web3(window.web3.currentProvider)
let ethContract = web3.eth.contract("LP合约Abi")
let functionInstance = ethContract.at("LP合约地址")
functionInstance.getReserves((err, res) => {
  if (!err) {
        // 代币数量1 res[0].toNumber()
        // 代币数量2 res[1].toNumber()
        //根据先后顺序 2个相除可以得到价格
    }
})