Electron开发入门

前记：

Electron是笔者最近才开始接触的Node中的一个模块，大致功能是将Node.js的环境搬至桌面程序开发中，也就是说我们可以通过Node.js去开发桌面程序，最终打包成exe可执行文件。因为之前笔者一直从事Java开发，对Node了解甚少，所以并不清楚实现这种功能是不是特别难，但是Electron的作者的实习经历及Electron目前所获得的成就（GitHub 60k+的Star）让笔者非常的钦佩。

Electron介绍

Electron安装

Node环境搭建
npm转淘宝镜像

npm install -g cnpm --registry=https://registry.npm.taobao.org
Electron模块安装

npm install -g electron
Electron打包模块安装

npm install -g electron-packager

Electron开发

目录结构

Github Demo地址：https://github.com/electron/electron-quick-start

electron/resources/app
|_package.json
|_main.js
|_index.html

这是一个传统的Node项目目录结构，package.json是应用的配置文件：

{
  "name": "xiaochongkk",
  "version": "2.0.0",
  "main": "main.js",
  "dependencies": {
    "cheerio": "^1.0.0-rc.2",
    "electron-packager": "^12.1.0",
    "superagent": "^3.8.3"
  },
  "scripts": {
    "test": "start",
    "start": "electron .",
    "packager": "electron-packager ../electron-practice --all --out ./out-electron-practice --electron-version 2.0.0 --overwrite "
  }
}

参数介绍：

name：应用名
version：版本号
main：主进程入口js文件
dependencies：依赖模块
scripts：可执行脚本，可在命令行执行
其他参数请参考 https://docs.npmjs.com/files/package.json

Electron使用main.js作为主进程启动入口，我们可以在其中渲染应用程序窗口及一些初始值，主要内容如下：

 // Modules to control application life and create native browser window
const {app, BrowserWindow} = require('electron')

// Keep a global reference of the window object, if you don't, the window will
// be closed automatically when the JavaScript object is garbage collected.
let mainWindow

function createWindow () {
  // Create the browser window.
  mainWindow = new BrowserWindow({width: 800, height: 600})

  // and load the index.html of the app.
  mainWindow.loadFile('index.html')

  // Open the DevTools.
  // mainWindow.webContents.openDevTools()

  // Emitted when the window is closed.
  mainWindow.on('closed', function () {
    // Dereference the window object, usually you would store windows
    // in an array if your app supports multi windows, this is the time
    // when you should delete the corresponding element.
    mainWindow = null
  })
}

// This method will be called when Electron has finished
// initialization and is ready to create browser windows.
// Some APIs can only be used after this event occurs.
app.on('ready', createWindow)

// Quit when all windows are closed.
app.on('window-all-closed', function () {
  // On OS X it is common for applications and their menu bar
  // to stay active until the user quits explicitly with Cmd + Q
  if (process.platform !== 'darwin') {
    app.quit()
  }
})

app.on('activate', function () {
  // On OS X it's common to re-create a window in the app when the
  // dock icon is clicked and there are no other windows open.
  if (mainWindow === null) {
    createWindow()
  }
})

// In this file you can include the rest of your app's specific main process
// code. You can also put them in separate files and require them here.

Electron程序运行

进入项目目录中执行npm start
项目目录中 electron #项目名

Electron程序打包

下载electron-packager模块
cnpm install -g electron-packager
编辑项目中的package.json, 增加scripts中增加packager配置：

"scripts":{
    "test": "start",
    "start": "electron .",
    "packager": "electron-packager ../electron-practice --all --out ./out-electron-practice --electron-version 2.0.0 --overwrite "
 }

参数介绍：
- electron-packager：后跟要打包的程序
- out：输出目录
- electron-version：electron版本
- overwrite：存在代表每次打包都覆盖已存在的目录
进入项目目录内执行：
cnpm run-script packager