【Electron】用前端技术开发桌面应用（一）

由于最近工作需求，紧急学习electron相关的技术知识，关于node.js的相关问题，后续会继续更新。

【electron】简介及作用：

electron的基本组成：Chromium + Node.js + Native API
Chromium：Google 的Chrome浏览器背后的引擎，为electron提供了强大的UI能力，不用考虑兼容性的问题，比如可以不用写很多CSS兼容代码；
Node.js：可以使用npm的包快速开发，并且使electron有底层开发的能力，比如文件的读写等；
Native API：使electron有跨平台和桌面端原生的能力
使用场景：
1、公司没有专门的桌面应用开发者，需要前端做桌面应用，比如现在苦逼的我；
2、一个项目要开发桌面端和web端，比如根据不同的权限，客户使用的端不一样；
3、要做一个效率工具，提高开发效率
具体应用举例：
VSCode（前端常用工具），Atom（github文本编辑器），slack（国外应用，得翻墙用）

【安装electron】

先安装node.js 进入官网下载node.js，LST版本是长期稳定的版本，公司开发使用；最新版本可自己练习时使用 node.js安装官网
npm install electron --save-dev (开发环境安装)
查看是否安装成功：
npx electron -v （node版本5.0以上的版本才有npx）

创建一个hello world的electron

新建H5页面：index.html

<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Hello World</title>
</head>
<body>Hello World!
</body>
</html>

创建主进程文件：main.js

const electron = require('electron') // 引入electron
const app = electron.app // 引用app
const BrowserWindow = electron.BrowserWindow // 窗口引用
const mainWindow = null // 声明要打开的主窗口
// app.on监控事件
app.on('ready', ()=> {mainWindow = new BrowserWindow({height: 800,width: 800})mainWindow.loadFile('index.html') // 要加载的html的页面(本例的index.html文件与mian.js文件为同级目录)// win.loadURL('https://github.com')mainWindow.on('closed', ()=>{ mainWindow = null})
})

使用npm init --yes 自动生成package.json文件：

最后使用命令：electron . 运行，就可以看到hello world 的窗口。

【electron的运行流程】

#mermaid-svg-5pHeofNLQey2x8AD .label{font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family);fill:#333;color:#333}#mermaid-svg-5pHeofNLQey2x8AD .label text{fill:#333}#mermaid-svg-5pHeofNLQey2x8AD .node rect,#mermaid-svg-5pHeofNLQey2x8AD .node circle,#mermaid-svg-5pHeofNLQey2x8AD .node ellipse,#mermaid-svg-5pHeofNLQey2x8AD .node polygon,#mermaid-svg-5pHeofNLQey2x8AD .node path{fill:#ECECFF;stroke:#9370db;stroke-width:1px}#mermaid-svg-5pHeofNLQey2x8AD .node .label{text-align:center;fill:#333}#mermaid-svg-5pHeofNLQey2x8AD .node.clickable{cursor:pointer}#mermaid-svg-5pHeofNLQey2x8AD .arrowheadPath{fill:#333}#mermaid-svg-5pHeofNLQey2x8AD .edgePath .path{stroke:#333;stroke-width:1.5px}#mermaid-svg-5pHeofNLQey2x8AD .flowchart-link{stroke:#333;fill:none}#mermaid-svg-5pHeofNLQey2x8AD .edgeLabel{background-color:#e8e8e8;text-align:center}#mermaid-svg-5pHeofNLQey2x8AD .edgeLabel rect{opacity:0.9}#mermaid-svg-5pHeofNLQey2x8AD .edgeLabel span{color:#333}#mermaid-svg-5pHeofNLQey2x8AD .cluster rect{fill:#ffffde;stroke:#aa3;stroke-width:1px}#mermaid-svg-5pHeofNLQey2x8AD .cluster text{fill:#333}#mermaid-svg-5pHeofNLQey2x8AD div.mermaidTooltip{position:absolute;text-align:center;max-width:200px;padding:2px;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family);font-size:12px;background:#ffffde;border:1px solid #aa3;border-radius:2px;pointer-events:none;z-index:100}#mermaid-svg-5pHeofNLQey2x8AD .actor{stroke:#ccf;fill:#ECECFF}#mermaid-svg-5pHeofNLQey2x8AD text.actor>tspan{fill:#000;stroke:none}#mermaid-svg-5pHeofNLQey2x8AD .actor-line{stroke:grey}#mermaid-svg-5pHeofNLQey2x8AD .messageLine0{stroke-width:1.5;stroke-dasharray:none;stroke:#333}#mermaid-svg-5pHeofNLQey2x8AD .messageLine1{stroke-width:1.5;stroke-dasharray:2, 2;stroke:#333}#mermaid-svg-5pHeofNLQey2x8AD #arrowhead path{fill:#333;stroke:#333}#mermaid-svg-5pHeofNLQey2x8AD .sequenceNumber{fill:#fff}#mermaid-svg-5pHeofNLQey2x8AD #sequencenumber{fill:#333}#mermaid-svg-5pHeofNLQey2x8AD #crosshead path{fill:#333;stroke:#333}#mermaid-svg-5pHeofNLQey2x8AD .messageText{fill:#333;stroke:#333}#mermaid-svg-5pHeofNLQey2x8AD .labelBox{stroke:#ccf;fill:#ECECFF}#mermaid-svg-5pHeofNLQey2x8AD .labelText,#mermaid-svg-5pHeofNLQey2x8AD .labelText>tspan{fill:#000;stroke:none}#mermaid-svg-5pHeofNLQey2x8AD .loopText,#mermaid-svg-5pHeofNLQey2x8AD .loopText>tspan{fill:#000;stroke:none}#mermaid-svg-5pHeofNLQey2x8AD .loopLine{stroke-width:2px;stroke-dasharray:2, 2;stroke:#ccf;fill:#ccf}#mermaid-svg-5pHeofNLQey2x8AD .note{stroke:#aa3;fill:#fff5ad}#mermaid-svg-5pHeofNLQey2x8AD .noteText,#mermaid-svg-5pHeofNLQey2x8AD .noteText>tspan{fill:#000;stroke:none}#mermaid-svg-5pHeofNLQey2x8AD .activation0{fill:#f4f4f4;stroke:#666}#mermaid-svg-5pHeofNLQey2x8AD .activation1{fill:#f4f4f4;stroke:#666}#mermaid-svg-5pHeofNLQey2x8AD .activation2{fill:#f4f4f4;stroke:#666}#mermaid-svg-5pHeofNLQey2x8AD .mermaid-main-font{font-family:"trebuchet ms", verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-5pHeofNLQey2x8AD .section{stroke:none;opacity:0.2}#mermaid-svg-5pHeofNLQey2x8AD .section0{fill:rgba(102,102,255,0.49)}#mermaid-svg-5pHeofNLQey2x8AD .section2{fill:#fff400}#mermaid-svg-5pHeofNLQey2x8AD .section1,#mermaid-svg-5pHeofNLQey2x8AD .section3{fill:#fff;opacity:0.2}#mermaid-svg-5pHeofNLQey2x8AD .sectionTitle0{fill:#333}#mermaid-svg-5pHeofNLQey2x8AD .sectionTitle1{fill:#333}#mermaid-svg-5pHeofNLQey2x8AD .sectionTitle2{fill:#333}#mermaid-svg-5pHeofNLQey2x8AD .sectionTitle3{fill:#333}#mermaid-svg-5pHeofNLQey2x8AD .sectionTitle{text-anchor:start;font-size:11px;text-height:14px;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-5pHeofNLQey2x8AD .grid .tick{stroke:#d3d3d3;opacity:0.8;shape-rendering:crispEdges}#mermaid-svg-5pHeofNLQey2x8AD .grid .tick text{font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-5pHeofNLQey2x8AD .grid path{stroke-width:0}#mermaid-svg-5pHeofNLQey2x8AD .today{fill:none;stroke:red;stroke-width:2px}#mermaid-svg-5pHeofNLQey2x8AD .task{stroke-width:2}#mermaid-svg-5pHeofNLQey2x8AD .taskText{text-anchor:middle;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-5pHeofNLQey2x8AD .taskText:not([font-size]){font-size:11px}#mermaid-svg-5pHeofNLQey2x8AD .taskTextOutsideRight{fill:#000;text-anchor:start;font-size:11px;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-5pHeofNLQey2x8AD .taskTextOutsideLeft{fill:#000;text-anchor:end;font-size:11px}#mermaid-svg-5pHeofNLQey2x8AD .task.clickable{cursor:pointer}#mermaid-svg-5pHeofNLQey2x8AD .taskText.clickable{cursor:pointer;fill:#003163 !important;font-weight:bold}#mermaid-svg-5pHeofNLQey2x8AD .taskTextOutsideLeft.clickable{cursor:pointer;fill:#003163 !important;font-weight:bold}#mermaid-svg-5pHeofNLQey2x8AD .taskTextOutsideRight.clickable{cursor:pointer;fill:#003163 !important;font-weight:bold}#mermaid-svg-5pHeofNLQey2x8AD .taskText0,#mermaid-svg-5pHeofNLQey2x8AD .taskText1,#mermaid-svg-5pHeofNLQey2x8AD .taskText2,#mermaid-svg-5pHeofNLQey2x8AD .taskText3{fill:#fff}#mermaid-svg-5pHeofNLQey2x8AD .task0,#mermaid-svg-5pHeofNLQey2x8AD .task1,#mermaid-svg-5pHeofNLQey2x8AD .task2,#mermaid-svg-5pHeofNLQey2x8AD .task3{fill:#8a90dd;stroke:#534fbc}#mermaid-svg-5pHeofNLQey2x8AD .taskTextOutside0,#mermaid-svg-5pHeofNLQey2x8AD .taskTextOutside2{fill:#000}#mermaid-svg-5pHeofNLQey2x8AD .taskTextOutside1,#mermaid-svg-5pHeofNLQey2x8AD .taskTextOutside3{fill:#000}#mermaid-svg-5pHeofNLQey2x8AD .active0,#mermaid-svg-5pHeofNLQey2x8AD .active1,#mermaid-svg-5pHeofNLQey2x8AD .active2,#mermaid-svg-5pHeofNLQey2x8AD .active3{fill:#bfc7ff;stroke:#534fbc}#mermaid-svg-5pHeofNLQey2x8AD .activeText0,#mermaid-svg-5pHeofNLQey2x8AD .activeText1,#mermaid-svg-5pHeofNLQey2x8AD .activeText2,#mermaid-svg-5pHeofNLQey2x8AD .activeText3{fill:#000 !important}#mermaid-svg-5pHeofNLQey2x8AD .done0,#mermaid-svg-5pHeofNLQey2x8AD .done1,#mermaid-svg-5pHeofNLQey2x8AD .done2,#mermaid-svg-5pHeofNLQey2x8AD .done3{stroke:grey;fill:#d3d3d3;stroke-width:2}#mermaid-svg-5pHeofNLQey2x8AD .doneText0,#mermaid-svg-5pHeofNLQey2x8AD .doneText1,#mermaid-svg-5pHeofNLQey2x8AD .doneText2,#mermaid-svg-5pHeofNLQey2x8AD .doneText3{fill:#000 !important}#mermaid-svg-5pHeofNLQey2x8AD .crit0,#mermaid-svg-5pHeofNLQey2x8AD .crit1,#mermaid-svg-5pHeofNLQey2x8AD .crit2,#mermaid-svg-5pHeofNLQey2x8AD .crit3{stroke:#f88;fill:red;stroke-width:2}#mermaid-svg-5pHeofNLQey2x8AD .activeCrit0,#mermaid-svg-5pHeofNLQey2x8AD .activeCrit1,#mermaid-svg-5pHeofNLQey2x8AD .activeCrit2,#mermaid-svg-5pHeofNLQey2x8AD .activeCrit3{stroke:#f88;fill:#bfc7ff;stroke-width:2}#mermaid-svg-5pHeofNLQey2x8AD .doneCrit0,#mermaid-svg-5pHeofNLQey2x8AD .doneCrit1,#mermaid-svg-5pHeofNLQey2x8AD .doneCrit2,#mermaid-svg-5pHeofNLQey2x8AD .doneCrit3{stroke:#f88;fill:#d3d3d3;stroke-width:2;cursor:pointer;shape-rendering:crispEdges}#mermaid-svg-5pHeofNLQey2x8AD .milestone{transform:rotate(45deg) scale(0.8, 0.8)}#mermaid-svg-5pHeofNLQey2x8AD .milestoneText{font-style:italic}#mermaid-svg-5pHeofNLQey2x8AD .doneCritText0,#mermaid-svg-5pHeofNLQey2x8AD .doneCritText1,#mermaid-svg-5pHeofNLQey2x8AD .doneCritText2,#mermaid-svg-5pHeofNLQey2x8AD .doneCritText3{fill:#000 !important}#mermaid-svg-5pHeofNLQey2x8AD .activeCritText0,#mermaid-svg-5pHeofNLQey2x8AD .activeCritText1,#mermaid-svg-5pHeofNLQey2x8AD .activeCritText2,#mermaid-svg-5pHeofNLQey2x8AD .activeCritText3{fill:#000 !important}#mermaid-svg-5pHeofNLQey2x8AD .titleText{text-anchor:middle;font-size:18px;fill:#000;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-5pHeofNLQey2x8AD g.classGroup text{fill:#9370db;stroke:none;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family);font-size:10px}#mermaid-svg-5pHeofNLQey2x8AD g.classGroup text .title{font-weight:bolder}#mermaid-svg-5pHeofNLQey2x8AD g.clickable{cursor:pointer}#mermaid-svg-5pHeofNLQey2x8AD g.classGroup rect{fill:#ECECFF;stroke:#9370db}#mermaid-svg-5pHeofNLQey2x8AD g.classGroup line{stroke:#9370db;stroke-width:1}#mermaid-svg-5pHeofNLQey2x8AD .classLabel .box{stroke:none;stroke-width:0;fill:#ECECFF;opacity:0.5}#mermaid-svg-5pHeofNLQey2x8AD .classLabel .label{fill:#9370db;font-size:10px}#mermaid-svg-5pHeofNLQey2x8AD .relation{stroke:#9370db;stroke-width:1;fill:none}#mermaid-svg-5pHeofNLQey2x8AD .dashed-line{stroke-dasharray:3}#mermaid-svg-5pHeofNLQey2x8AD #compositionStart{fill:#9370db;stroke:#9370db;stroke-width:1}#mermaid-svg-5pHeofNLQey2x8AD #compositionEnd{fill:#9370db;stroke:#9370db;stroke-width:1}#mermaid-svg-5pHeofNLQey2x8AD #aggregationStart{fill:#ECECFF;stroke:#9370db;stroke-width:1}#mermaid-svg-5pHeofNLQey2x8AD #aggregationEnd{fill:#ECECFF;stroke:#9370db;stroke-width:1}#mermaid-svg-5pHeofNLQey2x8AD #dependencyStart{fill:#9370db;stroke:#9370db;stroke-width:1}#mermaid-svg-5pHeofNLQey2x8AD #dependencyEnd{fill:#9370db;stroke:#9370db;stroke-width:1}#mermaid-svg-5pHeofNLQey2x8AD #extensionStart{fill:#9370db;stroke:#9370db;stroke-width:1}#mermaid-svg-5pHeofNLQey2x8AD #extensionEnd{fill:#9370db;stroke:#9370db;stroke-width:1}#mermaid-svg-5pHeofNLQey2x8AD .commit-id,#mermaid-svg-5pHeofNLQey2x8AD .commit-msg,#mermaid-svg-5pHeofNLQey2x8AD .branch-label{fill:lightgrey;color:lightgrey;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-5pHeofNLQey2x8AD .pieTitleText{text-anchor:middle;font-size:25px;fill:#000;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-5pHeofNLQey2x8AD .slice{font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-5pHeofNLQey2x8AD g.stateGroup text{fill:#9370db;stroke:none;font-size:10px;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-5pHeofNLQey2x8AD g.stateGroup text{fill:#9370db;fill:#333;stroke:none;font-size:10px}#mermaid-svg-5pHeofNLQey2x8AD g.statediagram-cluster .cluster-label text{fill:#333}#mermaid-svg-5pHeofNLQey2x8AD g.stateGroup .state-title{font-weight:bolder;fill:#000}#mermaid-svg-5pHeofNLQey2x8AD g.stateGroup rect{fill:#ECECFF;stroke:#9370db}#mermaid-svg-5pHeofNLQey2x8AD g.stateGroup line{stroke:#9370db;stroke-width:1}#mermaid-svg-5pHeofNLQey2x8AD .transition{stroke:#9370db;stroke-width:1;fill:none}#mermaid-svg-5pHeofNLQey2x8AD .stateGroup .composit{fill:white;border-bottom:1px}#mermaid-svg-5pHeofNLQey2x8AD .stateGroup .alt-composit{fill:#e0e0e0;border-bottom:1px}#mermaid-svg-5pHeofNLQey2x8AD .state-note{stroke:#aa3;fill:#fff5ad}#mermaid-svg-5pHeofNLQey2x8AD .state-note text{fill:black;stroke:none;font-size:10px}#mermaid-svg-5pHeofNLQey2x8AD .stateLabel .box{stroke:none;stroke-width:0;fill:#ECECFF;opacity:0.7}#mermaid-svg-5pHeofNLQey2x8AD .edgeLabel text{fill:#333}#mermaid-svg-5pHeofNLQey2x8AD .stateLabel text{fill:#000;font-size:10px;font-weight:bold;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-5pHeofNLQey2x8AD .node circle.state-start{fill:black;stroke:black}#mermaid-svg-5pHeofNLQey2x8AD .node circle.state-end{fill:black;stroke:white;stroke-width:1.5}#mermaid-svg-5pHeofNLQey2x8AD #statediagram-barbEnd{fill:#9370db}#mermaid-svg-5pHeofNLQey2x8AD .statediagram-cluster rect{fill:#ECECFF;stroke:#9370db;stroke-width:1px}#mermaid-svg-5pHeofNLQey2x8AD .statediagram-cluster rect.outer{rx:5px;ry:5px}#mermaid-svg-5pHeofNLQey2x8AD .statediagram-state .divider{stroke:#9370db}#mermaid-svg-5pHeofNLQey2x8AD .statediagram-state .title-state{rx:5px;ry:5px}#mermaid-svg-5pHeofNLQey2x8AD .statediagram-cluster.statediagram-cluster .inner{fill:white}#mermaid-svg-5pHeofNLQey2x8AD .statediagram-cluster.statediagram-cluster-alt .inner{fill:#e0e0e0}#mermaid-svg-5pHeofNLQey2x8AD .statediagram-cluster .inner{rx:0;ry:0}#mermaid-svg-5pHeofNLQey2x8AD .statediagram-state rect.basic{rx:5px;ry:5px}#mermaid-svg-5pHeofNLQey2x8AD .statediagram-state rect.divider{stroke-dasharray:10,10;fill:#efefef}#mermaid-svg-5pHeofNLQey2x8AD .note-edge{stroke-dasharray:5}#mermaid-svg-5pHeofNLQey2x8AD .statediagram-note rect{fill:#fff5ad;stroke:#aa3;stroke-width:1px;rx:0;ry:0}:root{--mermaid-font-family: '"trebuchet ms", verdana, arial';--mermaid-font-family: "Comic Sans MS", "Comic Sans", cursive}#mermaid-svg-5pHeofNLQey2x8AD .error-icon{fill:#522}#mermaid-svg-5pHeofNLQey2x8AD .error-text{fill:#522;stroke:#522}#mermaid-svg-5pHeofNLQey2x8AD .edge-thickness-normal{stroke-width:2px}#mermaid-svg-5pHeofNLQey2x8AD .edge-thickness-thick{stroke-width:3.5px}#mermaid-svg-5pHeofNLQey2x8AD .edge-pattern-solid{stroke-dasharray:0}#mermaid-svg-5pHeofNLQey2x8AD .edge-pattern-dashed{stroke-dasharray:3}#mermaid-svg-5pHeofNLQey2x8AD .edge-pattern-dotted{stroke-dasharray:2}#mermaid-svg-5pHeofNLQey2x8AD .marker{fill:#333}#mermaid-svg-5pHeofNLQey2x8AD .marker.cross{stroke:#333}:root { --mermaid-font-family: "trebuchet ms", verdana, arial;}#mermaid-svg-5pHeofNLQey2x8AD {color: rgba(0, 0, 0, 0.75);font: ;}

Package.json

主进程文件main.js

读取页面布局和演示

IPC执行任务和获取信息

1、读取package中设置的入口文件：这里设置的时是mian.js（一个electron有且只有一个主进程，一个主进程可以有多个渲染进程）

2、main.js主进程中创建渲染进程
3、读取需要渲染的应用页面的布局和样式
4、使用IPC在主进程执行任务并获取信息

【app 控制应用程序的事件生命周期】

详细介绍app控制应用程序的事件生命周期：
先引入app

const electron = require('electron')
const app = electron.app

app.on('ready', () => {})
当 Electron 完成初始化时，发出一次。也可以通过调用 app.isReady() 来检查该事件是否已被触发，以及通过 app.whenReady() 得到一个当Electron已初始化后fulfill 的 Promise。
‘before-quit’：在程序关闭窗口前发信号
‘activate’：当应用被激活时触发
app.on('window-all-closed', () => { app.quit() })
最后一个窗口被关闭时退出应用。此事件默认的行为是控制退出程序，但监听此事件可以控制什么条件下是否退出程序。