键盘快捷键

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2023-12-01

概览

该功能允许你为 Electron 应用程序配置应用和全局键盘快捷键。

示例

本地快捷键

应用键盘快捷键仅在应用程序被聚焦时触发。为了配置本地快捷键，你需要在创建Menu模块中的MenuItem时指定accelerator属性。

Starting with a working application from the Quick Start Guide, update the main.js file with the following lines:

index.html
main.js

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Hello World!</title>
    <meta http-equiv="Content-Security-Policy" content="script-src 'self' 'unsafe-inline';" />
</head>
<body>
    <h1>Hello World!</h1>
    <p>Hit Alt+Shift+I on Windows, or Opt+Cmd+I on mac to see a message printed to the console.</p>
</body>
</html>

const { app, BrowserWindow, Menu, MenuItem } = require('electron')

function createWindow () {
  const win = new BrowserWindow({
    width: 800,
    height: 600,
  })

  win.loadFile('index.html')
}

const menu = new Menu()
menu.append(new MenuItem({
  label: 'Electron',
  submenu: [{
    role: 'help',
    accelerator: process.platform === 'darwin' ? 'Alt+Cmd+I' : 'Alt+Shift+I',
    click: () => { console.log('Electron rocks!') }
  }]
}))

Menu.setApplicationMenu(menu)

app.whenReady().then(createWindow)

app.on('window-all-closed', () => {
  if (process.platform !== 'darwin') {
    app.quit()
  }
})

app.on('activate', () => {
  if (BrowserWindow.getAllWindows().length === 0) {
    createWindow()
  }
})

Open in Fiddle

注意：在上面的代码中，您可以看到基于用户的操作系统的 accelerator 差异。对于MacOS，是 Alt+Cmd+I，而对于Linux 和 Windows，则是 Alt+Shift+I.

启动 Electron 应用程序后，你应该看到应用程序菜单以及您刚刚定义的本地快捷方式：

带有本地快捷方式的菜单

如果你点击 Help 或按下定义的加速器，然后打开你运行的 Electron 应用程序的终端。将看到触发 click 事件后生成的消息：“Electron rocks！”

全局快捷键

要配置全局键盘快捷键，您需要使用 globalShortcon 模块来检测键盘事件，即使应用程序没有获得键盘焦点。

Starting with a working application from the Quick Start Guide, update the main.js file with the following lines:

index.html
main.js

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Hello World!</title>
    <meta http-equiv="Content-Security-Policy" content="script-src 'self' 'unsafe-inline';" />
</head>
<body>
    <h1>Hello World!</h1>
    <p>Hit Alt+Ctrl+I on Windows or Opt+Cmd+I on Mac to see a message printed to the console.</p>
</body>
</html>

const { app, BrowserWindow, globalShortcut } = require('electron')

function createWindow () {
  const win = new BrowserWindow({
    width: 800,
    height: 600,
  })

  win.loadFile('index.html')
}

app.whenReady().then(() => {
  globalShortcut.register('Alt+CommandOrControl+I', () => {
    console.log('Electron loves global shortcuts!')
  })
}).then(createWindow)

app.on('window-all-closed', () => {
  if (process.platform !== 'darwin') {
    app.quit()
  }
})

app.on('activate', () => {
  if (BrowserWindow.getAllWindows().length === 0) {
    createWindow()
  }
})

Open in Fiddle

注：在上面的代码中， CommandOrControl 意指在 macOS 上使用 Command ，在 Windows/Linux 上使用 Control 。

启动应用后，如果你按下定义好的全局快捷键，你将在启动的 Electron 应用控制台里面看到对应的日志输出

在浏览器窗口内的快捷方式

使用 web APIs

如果您想要在 BrowserWindow 中处理键盘快捷键，你可以在渲染进程中使用 addEventListener() API来监听 kepup 和 keydown DOM事件。

index.html
main.js
renderer.js

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <!-- https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP -->
    <meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self'">
    <meta http-equiv="X-Content-Security-Policy" content="default-src 'self'; script-src 'self'">
    <title>Hello World!</title>
  </head>
  <body>
    <h1>Hello World!</h1>
    
    <p>Hit any key with this window focused to see it captured here.</p>
    <div><span>Last Key Pressed: </span><span id="last-keypress"></span></div>
    <script src="./renderer.js"></script>
  </body>
</html>

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

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

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

}

// 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.whenReady().then(() => {
  createWindow()
  
  app.on('activate', function () {
    // On macOS 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 (BrowserWindow.getAllWindows().length === 0) createWindow()
  })
})

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

function handleKeyPress (event) {
  // You can put code here to handle the keypress.
  document.getElementById("last-keypress").innerText = event.key
  console.log(`You pressed ${event.key}`)
}

window.addEventListener('keyup', handleKeyPress, true)

Open in Fiddle

注意：第三个参数 true 表明了当前监听器会持续在其它监听器之前接收按键按下事件，因此无法在其它监听器中调用 stopPropagation()。

拦截主进程中的事件

在调度页面中的keydown和keyup事件之前，会发出before-input-event事件。它可以用于捕获和处理在菜单中不可见的自定义快捷方式。

Starting with a working application from the Quick Start Guide, update the main.js file with the following lines:

index.html
main.js

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Hello World!</title>
    <meta http-equiv="Content-Security-Policy" content="script-src 'self' 'unsafe-inline';" />
</head>
<body>
    <h1>Hello World!</h1>
    <p>Hit Ctrl+I to see a message printed to the console.</p>
</body>
</html>

const { app, BrowserWindow } = require('electron')

app.whenReady().then(() => {
  const win = new BrowserWindow({ width: 800, height: 600 })

  win.loadFile('index.html')
  win.webContents.on('before-input-event', (event, input) => {
    if (input.control && input.key.toLowerCase() === 'i') {
      console.log('Pressed Control+I')
      event.preventDefault()
    }
  })
})

Open in Fiddle

在运行Electron应用程序之后，如果你打开你运行Electron应用的终端并按下 Ctrl+I 组合键，你会发现刚才按下的组合键被成功拦截了。

使用第三方库

如果您不想手动进行快捷键解析，可以使用一些库来进行高级的按键检测。例如 mousetrap. 以下是在渲染进程中 mousetrap 的使用示例：

Mousetrap.bind('4', () => { console.log('4') })
Mousetrap.bind('?', () => { console.log('show shortcuts!') })
Mousetrap.bind('esc', () => { console.log('escape') }, 'keyup')

// combinations
Mousetrap.bind('command+shift+k', () => { console.log('command shift k') })

// map multiple combinations to the same callback
Mousetrap.bind(['command+k', 'ctrl+k'], () => {
  console.log('command k or control k')

  // return false to prevent default behavior and stop event from bubbling
  return false
})

// gmail style sequences
Mousetrap.bind('g i', () => { console.log('go to inbox') })
Mousetrap.bind('* a', () => { console.log('select all') })

// konami code!
Mousetrap.bind('up up down down left right left right b a enter', () => {
  console.log('konami code')
})