web前端培训分享Electron之Main Process API
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本节由千锋web前端培训机构讲师给大家分享Electron使用指南之Main Process API，Electron API （Electron API 有三种） Main Process （主进进程） Renderer Process（渲染进程） Share Modules（共享模块）
App
事件
ready:
当 Electron 完成初始化时被触发。
两种使用方法
app.on(‘ready’, createWindow)
app.on(‘ready’, () => {
console.log(‘App is ready!’)
createWindow()
})
检查应用是否登录：app.isReady()
如果应用没有Ready，app.isReady()的值为 false
console.log(‘应用是否登录：’ + app.isReady())
此时应用应该已经Ready
setTimeout(() => {
console.log(‘应用是否登录：’ + app.isReady())
}, 2000)
before-quit
在应用程序开始关闭窗口之前触发。
app.on(‘before-quit’, (e) => {
console.log(‘App is quiting’)
e.preventDefault()
})
browser-window-blur
在 browserWindow 失去焦点时发出
app.on(‘browser-window-blur’, (e) => {
console.log(‘App unfocused’)
})
browser-window-focus
在 browserWindow 获得焦点时发出
app.on(‘browser-window-focus’, (e) => {
console.log(‘App focused’)
})
方法
app.quit()
app.on(‘browser-window-blur’, (e) => {
setTimeout(() => {
app.quit()
}, 3000)
})
app.on(‘browser-window-blur’, (e) => {
setTimeout(app.quit, 3000)
})
app.getPath(name)
app.on(‘ready’, () => {
console.log(app.getPath(‘desktop’))
console.log(app.getPath(‘music’))
console.log(app.getPath(‘temp’))
console.log(app.getPath(‘userData’))
createWindow()
})
BrowserWindow
electron.BrowserWindow: 创建和控制浏览器窗口
实例方法
win.loadURL(url[, options]): 和 loadFile 互斥
mainWindow.loadURL(‘https://www.baidu.com’)
优雅的显示窗口
使用ready-to-show事件
let mainWindow = new BrowserWindow({ show: false })
mainWindow.once(‘ready-to-show’, () => {
mainWindow.show()
})
设置 backgroundColor
let win = new BrowserWindow({ backgroundColor: ‘#2e2c29’ })
父子窗口
窗口定义
secondaryWindow = new BrowserWindow({
width: 600,
height: 600,
webPreferences: { nodeIntegration: true }
})
secondaryWindow.loadFile(‘index.html’)
secondaryWindow.on(‘closed’, () => {
mainWindow = null
})
窗口关系
secondaryWindow = new BrowserWindow({
parent: mainWindon, // 定义父窗口
modal: true // 锁定在主窗口
})
子窗口显示和隐藏
secondaryWindow = new BrowserWindow({
show: false
})
setTimeout(() => {
secondaryWindow.show()
setTimeout(() => {
secondaryWindow.hide()
}, 3000)
}, 2000)
无边框窗口
Frameless Window
mainWindow = new BrowserWindow({
frame: false
})
让页面可拖拽
< body style=“user-select: none; -webkit-app-region:drag;”>
no-drag 修复下面控件的bug
< input style="-webkit-app-region: no-drag;" type=“range” name=“range” min=“0” max=“10”>
显示红绿灯
mainWindow = new BrowserWindow({
titleBarStyle: ‘hidden’ // or hiddenInset 距离红绿灯更近
})
属性与方法
minWidth && minHeight
mainWindow = new BrowserWindow({
minWidth: 300,
minHeight: 300
})
窗口焦点事件
secWindow = new BrowserWindow({
width: 400, height: 300,
webPreferences: { nodeIntegration: true },
})
mainWindow.on(‘focus’, () => {
console.log(‘mainWindow focused’)
})
secWindow.on(‘focus’, () => {
console.log(‘secWindow focused’)
})
app.on(‘browser-window-focus’, () => {
console.log(‘App focused’)
})
静态方法
getAllWindows()
let allWindows = BrowserWindow.getAllWindows()
console.log(allWindows)
实例属性
id
console.log(secWindow.id)
实例方法
maximize()secWindow.on(‘closed’, () => { mainWindow.maximize() })
state
electron-window-state 保存窗口的状态 npm install electron-window-state
webContents
webContents 是 EventEmitter 的实例， 负责渲染和控制网页, 是 BrowserWindow 对象的一个属性。 let wc = mainWindow.webContents console.log(wc)
方法 getAllWebContents(）
返回 WebContents[] - 所有 WebContents 实例的数组。 包含所有Windows，webviews，opened devtools 和 devtools 扩展背景页的 web 内容const {app, BrowserWindow, webContents} = require(‘electron’) console.log(webContents.getAllWebContents())
实例事件
did-finish-load
dom-ready
<div>
<img src="https://placekitten.com/500/500" alt="">
</div>
<script>
let wc = mainWindow.webContents
wc.on('did-finish-load', () => {
console.log('Conent fully loaded')
})
wc.on('dom-ready', () => {
console.log('DOM Ready')
})
</script>
new-window
<div>
<a target="_blank" href="https://placekitten.com/500/500"><h3>Kitten</h3></a>
</div>
<script>
wc.on('new-window', (e, url) => {
e.preventDefault()
console.log('DOM Ready')
})
</script>
before-input-event
wc.on('before-input-event', (e, input) => {
console.log(`${input.key} : ${input.type}`)
})
login
did-navigate
mainWindow.loadURL('https://httpbin.org/basic-auth/user/passwd')
wc.on('login', (e, request, authInfo, callback) => {
console.log('Logging in:')
callback('user', 'passwd')
})
wc.on('did-navigate', (e, url, statusCode, message) => {
console.log(`Navigated to: ${url}, with response code: ${statusCode}`)
console.log(message)
})
media-started-playing
media-paused
<div>
<video src="./mgm.mp4" controls width="400"></video>
</div>
<script>
wc.on('media-started-playing', () => {
console.log('Video Started')
})
wc.on('media-paused', () => {
console.log('Video Paused')
})
</script>
context-menu : 右键上下文信息
wc.on('context-menu', (e, params) => {
console.log(`Context menu opened on: ${params.mediaType} at x:${params.x}, y:${params.y}`)
})
wc.on('context-menu', (e, params) => {
console.log(`User seleted text: ${params.selectionText}`)
console.log(`Selection can be copied: ${params.editFlags.canCopy}`)
})
实例方法
executejavascript()
wc.on(‘context-menu’, (e, params) => {
wc.executeJavaScript(alert('${params.selectionText}'))
})
Session
管理浏览器会话、cookie、缓存、代理设置等。
起步
创建session对象
let session = mainWindow.webContents.session
console.log(session) // {}
在chromium 创建localStorage，然后创建两个窗口，两个session共享
mainWindow = new BrowserWindow({
width: 1000, height: 800,
webPreferences: { nodeIntegration: true }
})
secWindow = new BrowserWindow({
width: 500, height: 400,
webPreferences: { nodeIntegration: true }
})
let session = mainWindow.webContents.session
let session2 = mainWindow.webContents.session
console.log(Object.is(session, session2)) // true
// Load index.html into the new BrowserWindow
mainWindow.loadFile(‘index.html’)
secWindow.loadFile(‘index.html’)
// Open DevTools - Remove for PRODUCTION!
mainWindow.webContents.openDevTools();
secWindow.webContents.openDevTools();
// Listen for window being closed
mainWindow.on(‘closed’, () => {
mainWindow = null
})
secWindow.on(‘closed’, () => {
secWindow = null
})
defaultSession
const {app, BrowserWindow, session} = require(‘electron’)
let ses = mainWindow.webContents.session
console.log(Object.is(session.defaultSession, ses)) // true
自定义session
let customSes = session.fromPartition(‘part1’)
console.log(Object.is(customSes, ses)) //false, 此时customSes 还是共享session
secWindow = new BrowserWindow({
width: 500, height: 400,
webPreferences: {
nodeIntegration: true,
session: customSes // 定义session, 此时子窗口有自己的session
}
})
// 在子窗口里创建localstorge: winName/secWindow
// 关闭所有窗口，发现创建的localstorage又消失了，因为此时的session存储在内存里，重新启动应用又消失了。可以加前缀persist，使其变为永久存储：
let customSes = session.fromPartition('persist:part1')
// 或者：
secWindow = new BrowserWindow({
width: 500, height: 400,
webPreferences: {
nodeIntegration: true,
- session: customSes
+ partition: 'persist:part1'
}
})
实例方法
ses.clearStorageData() // 删除主窗口的的storage
cookie
查询和修改一个会话的cookies
// 查询所有 cookies
session.defaultSession.cookies.get({})
.then((cookies) => {
console.log(cookies)
}).catch((error) => {
console.log(error)
})
// 查询所有与设置的 URL 相关的所有 cookies
session.defaultSession.cookies.get({ url: 'http://www.github.com' })
.then((cookies) => {
console.log(cookies)
}).catch((error) => {
console.log(error)
})
// 设置一个 cookie，使用设置的名称；
// 如果存在，则会覆盖原先 cookie.
const cookie = { url: 'http://www.github.com', name: 'dummy_name', value: 'dummy' }
session.defaultSession.cookies.set(cookie)
.then(() => {
// success
}, (error) => {
console.error(error)
})
downloadItem
控制来自于远程资源的文件下载。
<h2><a href="https://picsum.photos/5000/5000/" download>Download Image</a></h2>
<progress value="0" max="100" id="progress"></progress>
<script>
window.progress = document.getElementById('progress')
</script>
// main.js
let ses = session.defaultSession
ses.on('will-download', (e, downloadItem, webContents) => {
let fileName = downloadItem.getFilename()
let fileSize = downloadItem.getTotalBytes()
// Save to desktop
downloadItem.setSavePath(app.getPath('desktop') + `/${fileName}`)
downloadItem.on('updated', (e, state) => {
let received = downloadItem.getReceivedBytes()
if (state === 'progressing' && received) {
let progress = Math.round((received/fileSize)*100)
webContents.executeJavaScript(`window.progress.value = ${progress}`)
}
})
})
dialog - 对话框
显示用于打开和保存文件、警报等的本机系统对话框
const {app, BrowserWindow, dialog} = require('electron')
mainWindow.webContents.on('did-finish-load', () => {
dialog.showOpenDialog({
buttonLabel: '选择',
defaultPath: app.getPath('desktop'),
properties: ['multiSelections', 'createDirectory', 'openFile', 'openDirectory']
}, filepaths => {
console.log(filepaths)
})
})
dialog.showSaveDialog({}, filename => {
console.log(filename)
})
const answers = ['Yes', 'No', 'Maybe']
dialog.showMessageBox({
title: 'Message Box',
message: 'Please select an option',
detail: 'Message details.',
buttons: answers
}, response => {
console.log(`User selected: ${answers[response]}`)
})
快捷键+系统快捷键
快捷键：定义键盘快捷键。 系统快捷键：在应用程序没有键盘焦点时，监听键盘事件。
快捷键可以包含多个功能键和一个键码的字符串，由符号+结合，用来定义你应用中的键盘快捷键
示例：
CommandOrControl+A
CommandOrControl+Shift+Z
快捷方式使用 register 方法在 globalShortcut 模块中注册。
globalShortcut 模块可以在操作系统中注册/注销全局快捷键, 以便可以为操作定制各种快捷键。
注意: 快捷方式是全局的; 即使应用程序没有键盘焦点, 它也仍然在持续监听键盘事件。 在应用程序模块发出 ready 事件之前, 不应使用此模块。
const {app, BrowserWindow, globalShortcut} = require('electron')
globalShortcut.register('G', () => {
console.log('User pressed G')
})
globalShortcut.register('CommandOrControl+Y', () => {
console.log('User pressed G with a combination key')
globalShortcut.unregister('CommandOrControl+G')
})
Menu
1、index.html
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta http-equiv="Content-Security-Policy" content="script-src 'self' 'unsafe-inline'">
<title>Hello World!</title>
</head>
<body>
<h1>Hello World!</h1>
<textarea name="name" rows="8" cols="80"></textarea>
<!-- All of the Node.js APIs are available in this renderer process. -->
We are using Node.js <strong><script>document.write( process.versions.node)</script></strong>,
and Electron <strong><script>document.write( process.versions.electron )</script></strong>.
<script>
// You can also require other files to run in this process
require('./renderer.js')
</script>
</body>
</html>
2、main.js
// Modules
const {app, BrowserWindow, Menu, MenuItem} = 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
let mainMenu = Menu.buildFromTemplate( require('./mainMenu') )
// Create a new BrowserWindow when `app` is ready
function createWindow () {
mainWindow = new BrowserWindow({
width: 1000, height: 800,
webPreferences: { nodeIntegration: true }
})
// Load index.html into the new BrowserWindow
mainWindow.loadFile('index.html')
// Open DevTools - Remove for PRODUCTION!
mainWindow.webContents.openDevTools();
Menu.setApplicationMenu(mainMenu)
// Listen for window being closed
mainWindow.on('closed', () => {
mainWindow = null
})
}
// Electron `app` is ready
app.on('ready', createWindow)
// Quit when all windows are closed - (Not macOS - Darwin)
app.on('window-all-closed', () => {
if (process.platform !== 'darwin') app.quit()
})
// When app icon is clicked and app is running, (macOS) recreate the BrowserWindow
app.on('activate', () => {
if (mainWindow === null) createWindow()
})
3、mainMenu.js
module.exports = [
{
label: 'Electron',
submenu: [
{ label: 'Item 1'},
{ label: 'Item 2', submenu: [ { label: 'Sub Item 1'} ]},
{ label: 'Item 3'},
]
},
{
label: 'Edit',
submenu: [
{ role: 'undo'},
{ role: 'redo'},
{ role: 'copy'},
{ role: 'paste'},
]
},
{
label: 'Actions',
submenu: [
{
label: 'DevTools',
role: 'toggleDevTools'
},
{
role: 'toggleFullScreen'
},
{
label: 'Greet',
click: () => { console.log('Hello from Main Menu') },
accelerator: 'Shift+Alt+G'
}
]
}
]
Context Menus
1、index.html
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta http-equiv="Content-Security-Policy" content="script-src 'self' 'unsafe-inline'">
<title>Hello World!</title>
</head>
<body>
<h1>Hello World!</h1>
<textarea name="name" rows="8" cols="80"></textarea>
<!-- All of the Node.js APIs are available in this renderer process. -->
We are using Node.js <strong><script>document.write( process.versions.node)</script></strong>,
and Electron <strong><script>document.write( process.versions.electron )</script></strong>.
<script>
// You can also require other files to run in this process
require('./renderer.js')
</script>
</body>
</html>
2、main.js
// Modules
const {app, BrowserWindow, Menu} = 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
let contextMenu = Menu.buildFromTemplate([
{ label: 'Item 1' },
{ role: 'editMenu' }
])
// Create a new BrowserWindow when `app` is ready
function createWindow () {
mainWindow = new BrowserWindow({
width: 1000, height: 800,
webPreferences: { nodeIntegration: true }
})
// Load index.html into the new BrowserWindow
mainWindow.loadFile('index.html')
// Open DevTools - Remove for PRODUCTION!
mainWindow.webContents.openDevTools();
mainWindow.webContents.on('context-menu', e => {
contextMenu.popup()
})
// Listen for window being closed
mainWindow.on('closed', () => {
mainWindow = null
})
}
// Electron `app` is ready
app.on('ready', createWindow)
// Quit when all windows are closed - (Not macOS - Darwin)
app.on('window-all-closed', () => {
if (process.platform !== 'darwin') app.quit()
})
// When app icon is clicked and app is running, (macOS) recreate the BrowserWindow
app.on('activate', () => {
if (mainWindow === null) createWindow()
})
Tray (托盘)
1、main.js
// Modules
const {app, BrowserWindow, Tray, Menu} = 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, tray
let trayMenu = Menu.buildFromTemplate([
{ label: 'Item 1' },
{ role: 'quit' }
])
function createTray() {
tray = new Tray('trayTemplate@2x.png')
tray.setToolTip('Tray details')
tray.on('click', e => {
if (e.shiftKey) {
app.quit()
} else {
mainWindow.isVisible() ? mainWindow.hide() : mainWindow.show()
}
})
tray.setContextMenu(trayMenu)
}
// Create a new BrowserWindow when `app` is ready
function createWindow () {
createTray()
mainWindow = new BrowserWindow({
width: 1000, height: 800,
webPreferences: { nodeIntegration: true }
})
// Load index.html into the new BrowserWindow
mainWindow.loadFile('index.html')
// Open DevTools - Remove for PRODUCTION!
mainWindow.webContents.openDevTools();
// Listen for window being closed
mainWindow.on('closed', () => {
mainWindow = null
})
}
// Electron `app` is ready
app.on('ready', createWindow)
// Quit when all windows are closed - (Not macOS - Darwin)
app.on('window-all-closed', () => {
if (process.platform !== 'darwin') app.quit()
})
// When app icon is clicked and app is running, (macOS) recreate the BrowserWindow
app.on('activate', () => {
if (mainWindow === null) createWindow()
})
powerMonitor (电源指示器)
// Modules
const electron = require('electron')
const {app, BrowserWindow} = 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
// Create a new BrowserWindow when `app` is ready
function createWindow () {
mainWindow = new BrowserWindow({
width: 1000, height: 800,
webPreferences: { nodeIntegration: true }
})
// Load index.html into the new BrowserWindow
mainWindow.loadFile('index.html')
// Open DevTools - Remove for PRODUCTION!
mainWindow.webContents.openDevTools();
// Listen for window being closed
mainWindow.on('closed', () => {
mainWindow = null
})
electron.powerMonitor.on('resume', e => {
if(!mainWindow) createWindow()
})
electron.powerMonitor.on('suspend', e => {
console.log('Saving some data')
})
}
// Electron `app` is ready
app.on('ready', createWindow)
// Quit when all windows are closed - (Not macOS - Darwin)
app.on('window-all-closed', () => {
if (process.platform !== 'darwin') app.quit()
})
// When app icon is clicked and app is running, (macOS) recreate the BrowserWindow
app.on('activate', () => {
if (mainWindow === null) createWindow()
})
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