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Electron Desktop App Development · Leçon

Gérer les événements du cycle de vie de l’application

Gérez différents événements du cycle de vie de l’application, comme `ready`, `window-all-closed`, `activate` et `quit`, afin de garantir son bon fonctionnement.

Gérer les événements du cycle de vie de l’application est une leçon Electron Desktop App Development gratuite sur CoddyKit. Ceci est la leçon 1 sur 4. Tu peux lire la leçon complète ci-dessous gratuitement — puis la pratiquer en direct dans le navigateur avec un éditeur de code intégré et un tuteur IA 24/7. Elle fait partie du parcours d'apprentissage Electron Desktop App Development, et ta progression se synchronise sur le web et l'application CoddyKit. Le cours Electron Desktop App Development comprend 4 leçons au total.

Certaines parties de cette leçon n'ont pas encore été traduites et s'affichent en anglais.

App's Journey: Lifecycle Events

Just like people, software applications have a lifecycle! They start, run, and eventually close. In Electron, these stages are managed through "lifecycle events".

  • These events let your app react to important moments, like when it's ready to show a window or when all its windows are closed.
  • Properly handling them ensures your app behaves predictably and professionally on different operating systems.

Meet the `app` Module

Electron provides a special module called app. This module is the heart of your application's lifecycle management.

  • You use the app module to control your application's events.
  • It allows you to listen for events like when the app is ready, when windows close, or when the app is about to quit.
  • It also provides methods to manage the app, such as quitting or restarting.

App is Ready! The `ready` Event

The ready event is the most fundamental lifecycle event. It fires when Electron has finished initializing and is ready to create browser windows and interact with the system.

You must wait for this event before performing most operations. Try running this simple example:

const { app } = require('electron');

app.on('ready', () => {
  console.log('Electron app is ready!');
  // In a real app, you'd create windows here.
});

// Minimal handler to allow the app to quit when needed
app.on('window-all-closed', () => {
  if (process.platform !== 'darwin') {
    app.quit();
  }
});

Launching Your First Window

The ready event is typically where you create your application's main window. This ensures the Electron environment is fully initialized before the UI appears.

We import BrowserWindow and create an instance, loading simple HTML content directly.

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

let mainWindow;

function createWindow () {
  mainWindow = new BrowserWindow({
    width: 400,
    height: 300
  });

  // Load a simple HTML string directly for a self-contained example
  mainWindow.loadURL('data:text/html;charset=utf-8,<h1>Hello Electron!</h1><p>This is your window.</p>');

  mainWindow.on('closed', () => {
    mainWindow = null;
  });
}

app.on('ready', createWindow);

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

Closing All Windows? `window-all-closed`

The window-all-closed event fires when all of your application's windows have been closed. How you respond depends on the operating system.

  • On Windows and Linux, apps usually quit when all windows close.
  • On macOS, apps often stay active in the dock.

This code ensures the app quits on Windows/Linux but stays open on macOS.

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

let mainWindow;

function createWindow () {
  mainWindow = new BrowserWindow({
    width: 400,
    height: 300
  });
  mainWindow.loadURL('data:text/html;charset=utf-8,<h1>Close Me!</h1>');
  mainWindow.on('closed', () => {
    mainWindow = null;
  });
}

app.on('ready', createWindow);

app.on('window-all-closed', () => {
  // On macOS, it's common for apps to remain active in the dock
  // until the user quits explicitly with Cmd + Q.
  if (process.platform !== 'darwin') {
    app.quit();
  }
});

Reactivating Your macOS App

The activate event is specific to macOS. It fires when the application is activated, typically when the user clicks on the app's icon in the dock, but no windows are currently open.

This is where you'd re-create a window if mainWindow is null.

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

let mainWindow;

function createWindow () {
  mainWindow = new BrowserWindow({
    width: 400,
    height: 300
  });
  mainWindow.loadURL('data:text/html;charset=utf-8,<h1>Activated!</h1><p>A new window was opened.</p>');
  mainWindow.on('closed', () => {
    mainWindow = null;
  });
}

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

app.on('activate', () => {
  // On macOS, re-create a window when the dock icon is clicked
  // and there are no other windows open.
  if (mainWindow === null) {
    createWindow();
  }
});

Last Chance: `will-quit`

The will-quit event fires just before the application begins to close its windows and quit. This is your last opportunity to perform synchronous cleanup operations.

  • For example, you might save unsaved data or close database connections.
  • This event is emitted before the quit event.
const { app, BrowserWindow } = require('electron');

let mainWindow;

function createWindow () {
  mainWindow = new BrowserWindow({
    width: 400,
    height: 300
  });
  mainWindow.loadURL('data:text/html;charset=utf-8,<h1>Will Quit Demo</h1>');
  mainWindow.on('closed', () => { mainWindow = null; });
}

app.on('ready', createWindow);
app.on('window-all-closed', () => { if (process.platform !== 'darwin') { app.quit(); } });
app.on('activate', () => { if (mainWindow === null) { createWindow(); } });

app.on('will-quit', (event) => {
  console.log('Application is about to quit! Performing final cleanup...');
  // event.preventDefault(); // Uncomment to prevent quitting
  // Perform synchronous cleanup here, e.g., save data.
});

The Final Goodbye: `quit`

The quit event is emitted when the application successfully exits. By this point, all windows have been closed, and the main process is shutting down.

  • This event is primarily for logging or very simple, final notifications.
  • It's generally too late to perform significant cleanup or prevent the app from quitting.
const { app, BrowserWindow } = require('electron');

let mainWindow;

function createWindow () {
  mainWindow = new BrowserWindow({
    width: 400,
    height: 300
  });
  mainWindow.loadURL('data:text/html;charset=utf-8,<h1>Quit Demo</h1>');
  mainWindow.on('closed', () => { mainWindow = null; });
}

app.on('ready', createWindow);
app.on('window-all-closed', () => { if (process.platform !== 'darwin') { app.quit(); } });
app.on('activate', () => { if (mainWindow === null) { createWindow(); } });
app.on('will-quit', () => { console.log('Will quit...'); });

app.on('quit', (event, exitCode) => {
  console.log(`Application has quit with code: ${exitCode}`);
  // This is the very last event.
});

Lifecycle Event Check

You've learned about several key Electron application lifecycle events. Now, let's test your understanding!

Lifecycle Events: Key Takeaways

Great job! You've learned how to manage your Electron application's lifecycle, ensuring it starts, runs, and quits gracefully on different operating systems.

  • The app module is central to event handling.
  • ready is crucial for initialization and window creation.
  • window-all-closed and activate handle window behavior across platforms.
  • will-quit and quit manage the final stages of app termination.

Mastering these events is fundamental for building robust Electron applications. Keep practicing!

Questions Fréquemment Posées

La leçon « Gérer les événements du cycle de vie de l’application » est-elle gratuite ?

Oui — le texte complet de « Gérer les événements du cycle de vie de l’application » est gratuit à lire ici sur le web. Pour la pratiquer de manière interactive (un éditeur de code intégré et un tuteur IA 24/7) et déverrouiller le reste du cours Electron Desktop App Development, passe à CoddyKit PRO. Le cours Electron Desktop App Development comprend 4 leçons au total.

Qu'est-ce que j'apprendrai dans « Gérer les événements du cycle de vie de l’application » ?

Gérez différents événements du cycle de vie de l’application, comme `ready`, `window-all-closed`, `activate` et `quit`, afin de garantir son bon fonctionnement. Tu pratiques Electron Desktop App Development avec du code pratique que tu exécutes directement dans le navigateur, et un tuteur IA 24/7 répond à tes questions au fur et à mesure que tu avances dans la leçon.

Dois-je avoir de l'expérience pour commencer Electron Desktop App Development ?

Aucune expérience préalable n'est requise. Electron Desktop App Development sur CoddyKit est structuré pour les débutants jusqu'aux apprenants avancés, donc tu peux commencer ici ou depuis le début et avancer à ton rythme. Ceci est la leçon 1 sur 4.

Combien de temps prend la leçon « Gérer les événements du cycle de vie de l’application » ?

La plupart des leçons CoddyKit prennent environ 5–10 minutes. Chacune est courte et interactive, tu progresses régulièrement et tu repiques exactement où tu t'es arrêté sur le web et l'app.

Peux-tu écrire et exécuter du code dans cette leçon Electron Desktop App Development ?

Oui. Chaque leçon Electron Desktop App Development inclut un éditeur de code intégré, tu écris et exécutes du vrai code directement dans ton navigateur et tu reçois des retours IA instantanés — aucune configuration locale requise.

Toutes les leçons de ce cours

  1. Gérer les événements du cycle de vie de l’application
  2. Mettre en œuvre les mises à jour automatiques
  3. Rapports d’erreurs
  4. Liens profonds et gestionnaires de protocoles
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