事件系统

Wails 提供用于发布/订阅通信的统一事件系统。你可以在任何位置发出和监听事件——从 Go 到 JavaScript、从 JavaScript 到 Go，以及从一个窗口到另一个窗口——借助类型化事件和生命周期钩子实现解耦架构。

快速入门

Go（发出）：

app.Event.Emit("user-logged-in", map[string]interface{}{
    "userId": 123,
    "name": "Alice",
})

JavaScript（监听）：

javascript

import { Events } from '@wailsio/runtime'

Events.On("user-logged-in", (event) => {
    console.log(`User ${event.data.name} logged in`)
})

就是这样！跨语言发布/订阅。

事件类型

自定义事件

应用专用事件：

// Emit from Go
app.Event.Emit("order-created", order)
app.Event.Emit("payment-processed", payment)
app.Event.Emit("notification", message)

javascript

// Listen in JavaScript
Events.On("order-created", handleOrder)
Events.On("payment-processed", handlePayment)
Events.On("notification", showNotification)

系统事件

内置操作系统和应用事件：

import "github.com/wailsapp/wails/v3/pkg/events"

// Theme changes
app.Event.OnApplicationEvent(events.Common.ThemeChanged, func(e *application.ApplicationEvent) {
    if e.Context().IsDarkMode() {
        app.Logger.Info("Dark mode enabled")
    }
})

// Application lifecycle
app.Event.OnApplicationEvent(events.Common.ApplicationStarted, func(e *application.ApplicationEvent) {
    app.Logger.Info("Application started")
})

窗口事件

窗口专用事件：

window.OnWindowEvent(events.Common.WindowFocus, func(e *application.WindowEvent) {
    app.Logger.Info("Window focused")
})

window.OnWindowEvent(events.Common.WindowClosing, func(e *application.WindowEvent) {
    app.Logger.Info("Window closing")
})

发出事件

从 Go 发出

基本发出方式：

app.Event.Emit("event-name", data)

使用不同的数据类型：

// String
app.Event.Emit("message", "Hello")

// Number
app.Event.Emit("count", 42)

// Struct
app.Event.Emit("user", User{ID: 1, Name: "Alice"})

// Map
app.Event.Emit("config", map[string]interface{}{
    "theme": "dark",
    "fontSize": 14,
})

// Array
app.Event.Emit("items", []string{"a", "b", "c"})

向特定窗口发出：

window.EmitEvent("window-specific-event", data)

从 JavaScript 发出

javascript

import { Events } from '@wailsio/runtime'

// Emit to Go
Events.Emit("button-clicked", { buttonId: "submit" })

// Emit to all windows
Events.Emit("broadcast-message", "Hello everyone")

监听事件

在 Go 中

应用事件：

app.Event.On("custom-event", func(e *application.CustomEvent) {
    data := e.Data
    // Handle event
})

使用类型断言：

app.Event.On("user-updated", func(e *application.CustomEvent) {
    user := e.Data.(User)
    app.Logger.Info("User updated", "name", user.Name)
})

多个处理程序：

// All handlers will be called
app.Event.On("order-created", logOrder)
app.Event.On("order-created", sendEmail)
app.Event.On("order-created", updateInventory)

在 JavaScript 中

基本监听器：

javascript

import { Events } from '@wailsio/runtime'

Events.On("event-name", (event) => {
    console.log("Event received:", event.data)
})

包含清理操作：

javascript

const unsubscribe = Events.On("event-name", handleEvent)

// Later, stop listening
unsubscribe()

多个处理程序：

javascript

Events.On("data-updated", updateUI)
Events.On("data-updated", saveToCache)
Events.On("data-updated", logChange)

一次性处理程序：

javascript

Events.Once("data-updated", updateVariable)

系统事件

应用事件

通用事件（跨平台）：

import "github.com/wailsapp/wails/v3/pkg/events"

// Application started
app.Event.OnApplicationEvent(events.Common.ApplicationStarted, func(e *application.ApplicationEvent) {
    app.Logger.Info("App started")
})

// Theme changed
app.Event.OnApplicationEvent(events.Common.ThemeChanged, func(e *application.ApplicationEvent) {
    isDark := e.Context().IsDarkMode()
    app.Event.Emit("theme-changed", isDark)
})

// System about to suspend
app.Event.OnApplicationEvent(events.Common.SystemWillSleep, func(e *application.ApplicationEvent) {
    flushPendingWrites()
})

// System resumed from suspend
app.Event.OnApplicationEvent(events.Common.SystemDidWake, func(e *application.ApplicationEvent) {
    reconnectSockets()
    refreshState()
})

// File opened
app.Event.OnApplicationEvent(events.Common.ApplicationOpenedWithFile, func(e *application.ApplicationEvent) {
    // Single-file: e.Context().Filename() returns ""; for multi-file launches
    // (Finder "Open With..." → multiple selection) use OpenedFiles().
    filePath := e.Context().Filename()
    openFile(filePath)
})

平台特定事件：

// Application became active
app.Event.OnApplicationEvent(events.Mac.ApplicationDidBecomeActive, func(e *application.ApplicationEvent) {
    app.Logger.Info("App became active")
})

// Application will terminate
app.Event.OnApplicationEvent(events.Mac.ApplicationWillTerminate, func(e *application.ApplicationEvent) {
    cleanup()
})

// System about to sleep / resumed
app.Event.OnApplicationEvent(events.Mac.ApplicationWillSleep, func(e *application.ApplicationEvent) {
    flushPendingWrites()
})
app.Event.OnApplicationEvent(events.Mac.ApplicationDidWake, func(e *application.ApplicationEvent) {
    refreshState()
})

// Displays sleeping/waking — distinct from system sleep (e.g. lid lowered)
app.Event.OnApplicationEvent(events.Mac.ApplicationScreensDidSleep, func(e *application.ApplicationEvent) {
    pauseRendering()
})
app.Event.OnApplicationEvent(events.Mac.ApplicationScreensDidWake, func(e *application.ApplicationEvent) {
    resumeRendering()
})

// Power status changed
app.Event.OnApplicationEvent(events.Windows.APMPowerStatusChange, func(e *application.ApplicationEvent) {
    app.Logger.Info("Power status changed")
})

// System suspending
app.Event.OnApplicationEvent(events.Windows.APMSuspend, func(e *application.ApplicationEvent) {
    saveState()
})

// System resumed. APMResumeAutomatic always fires on resume;
// APMResumeSuspend fires after it when the wake was triggered by
// user input. Prefer Common.SystemDidWake if you don't need to
// distinguish.
app.Event.OnApplicationEvent(events.Windows.APMResumeAutomatic, func(e *application.ApplicationEvent) {
    refreshState()
})

// Application startup
app.Event.OnApplicationEvent(events.Linux.ApplicationStartup, func(e *application.ApplicationEvent) {
    app.Logger.Info("App starting")
})

// Theme changed
app.Event.OnApplicationEvent(events.Linux.SystemThemeChanged, func(e *application.ApplicationEvent) {
    updateTheme()
})

// System sleep/wake — sourced from systemd-logind's PrepareForSleep
// signal on the system bus. Requires logind/elogind exposing
// org.freedesktop.login1, so it may be unavailable on distros/setups
// without it (Alpine, Void, some Devuan setups).
app.Event.OnApplicationEvent(events.Linux.SystemWillSleep, func(e *application.ApplicationEvent) {
    flushPendingWrites()
})
app.Event.OnApplicationEvent(events.Linux.SystemDidWake, func(e *application.ApplicationEvent) {
    refreshState()
})

窗口事件

常见窗口事件：

// Window focus
window.OnWindowEvent(events.Common.WindowFocus, func(e *application.WindowEvent) {
    app.Logger.Info("Window focused")
})

// Window blur
window.OnWindowEvent(events.Common.WindowLostFocus, func(e *application.WindowEvent) {
    app.Logger.Info("Window blurred")
})

// Window closing
window.OnWindowEvent(events.Common.WindowClosing, func(e *application.WindowEvent) {
    if hasUnsavedChanges() {
        e.Cancel()  // Prevent close
    }
})

// Window closed
window.OnWindowEvent(events.Common.WindowClosing, func(e *application.WindowEvent) {
    cleanup()
})

事件钩子

钩子会在标准监听器之前运行，并且可以取消事件：

// Hook - runs first, can cancel
window.RegisterHook(events.Common.WindowClosing, func(e *application.WindowEvent) {
    if hasUnsavedChanges() {
        result := showConfirmdialog("Unsaved changes. Close anyway?")
        if result != "yes" {
            e.Cancel()  // Prevent window close
        }
    }
})

// Standard listener - runs after hooks
window.OnWindowEvent(events.Common.WindowClosing, func(e *application.WindowEvent) {
    app.Logger.Info("Window closing")
})

主要区别：

特性	钩子	标准监听器
执行顺序	最先执行，按注册顺序	在钩子之后执行，顺序不作保证
阻塞	同步执行，会阻塞下一个钩子	异步执行，不阻塞
能否取消	能	不能（已传播）
用例	控制流、验证	日志记录、副作用

事件模式

发布/订阅模式

// Publisher (service)
type OrderService struct {
    app *application.App
}

func (o *OrderService) CreateOrder(items []Item) (*Order, error) {
    order := &Order{Items: items}
    
    if err := o.saveOrder(order); err != nil {
        return nil, err
    }
    
    // Publish event
    o.app.Event.Emit("order-created", order)
    
    return order, nil
}

// Subscribers
app.Event.On("order-created", func(e *application.CustomEvent) {
    order := e.Data.(*Order)
    sendConfirmationEmail(order)
})

app.Event.On("order-created", func(e *application.CustomEvent) {
    order := e.Data.(*Order)
    updateInventory(order)
})

app.Event.On("order-created", func(e *application.CustomEvent) {
    order := e.Data.(*Order)
    logOrder(order)
})

请求/响应模式

// Frontend requests data
Emit("get-user-data", { userId: 123 })

// Backend responds
app.Event.On("get-user-data", func(e *application.CustomEvent) {
    data := e.Data.(map[string]interface{})
    userId := int(data["userId"].(float64))
    
    user := getUserFromDB(userId)
    
    // Send response
    app.Event.Emit("user-data-response", user)
})

javascript

// Frontend receives response
Events.On("user-data-response", (event) => {
    const user = event.data
    displayUser(user)
})

注意：对于请求/响应，使用绑定更合适。事件应用于通知。

广播模式

// Broadcast to all windows
app.Event.Emit("global-notification", "System update available")

// Each window handles it
Events.On("global-notification", (event) => {
    const message = event.data
    showNotification(message)
})

事件聚合

type EventAggregator struct {
    events []Event
    mu     sync.Mutex
}

func (ea *EventAggregator) Add(event Event) {
    ea.mu.Lock()
    defer ea.mu.Unlock()
    
    ea.events = append(ea.events, event)
    
    // Emit batch every 100 events
    if len(ea.events) >= 100 {
        app.Event.Emit("event-batch", ea.events)
        ea.events = nil
    }
}

完整示例

Go：

package main

import (
    "github.com/wailsapp/wails/v3/pkg/application"
    "github.com/wailsapp/wails/v3/pkg/events"
)

type NotificationService struct {
    app *application.App
}

func (n *NotificationService) Notify(message string) {
    // Emit to all windows
    n.app.Event.Emit("notification", map[string]interface{}{
        "message":   message,
        "timestamp": time.Now(),
    })
}

func main() {
    app := application.New(application.Options{
        Name: "Event Demo",
    })
    
    notifService := &NotificationService{app: app}
    
    // System events
    app.Event.OnApplicationEvent(events.Common.ThemeChanged, func(e *application.ApplicationEvent) {
        isDark := e.Context().IsDarkMode()
        app.Event.Emit("theme-changed", isDark)
    })
    
    // Custom events from frontend
    app.Event.On("user-action", func(e *application.CustomEvent) {
        data := e.Data.(map[string]interface{})
        action := data["action"].(string)
        
        app.Logger.Info("User action", "action", action)
        
        // Respond
        notifService.Notify("Action completed: " + action)
    })
    
    // Window events
    window := app.Window.New()
    
    window.OnWindowEvent(events.Common.WindowFocus, func(e *application.WindowEvent) {
        app.Event.Emit("window-focused", window.Name())
    })
    
    window.RegisterHook(events.Common.WindowClosing, func(e *application.WindowEvent) {
        // Confirm before close
        app.Event.Emit("confirm-close", nil)
        e.Cancel()  // Wait for confirmation
    })
    
    app.Run()
}

JavaScript：

javascript

import { Events } from '@wailsio/runtime'

// Listen for notifications
Events.On("notification", (event) => {
    showNotification(event.data.message)
})

// Listen for theme changes
Events.On("theme-changed", (event) => {
    const isDark = event.data
    document.body.classList.toggle('dark', isDark)
})

// Listen for window focus
Events.On("window-focused", (event) => {
    const windowName = event.data
    console.log(`Window ${windowName} focused`)
})

// Handle close confirmation
Events.On("confirm-close", (event) => {
    if (confirm("Close window?")) {
        Events.Emit("close-confirmed", true)
    }
})

// Emit user actions
document.getElementById('button').addEventListener('click', () => {
    Events.Emit("user-action", { action: "button-clicked" })
})

最佳实践

✅ 应该做

使用事件发送通知——单向通信
使用绑定处理请求——双向通信
保持事件名称一致——使用 kebab-case
记录事件数据的说明——其中包含哪些字段？
使用完毕后取消订阅——防止内存泄漏
使用钩子进行验证——控制事件流

❌ 不应该做

不要将事件用于 RPC——应改用绑定
不要过于频繁地发出事件 - 必要时批量处理
不要在处理程序中阻塞 - 保持快速执行
不要忘记取消订阅 - 否则会导致内存泄漏
不要使用事件传输大量数据 - 请使用绑定
不要形成事件循环 - A 发出 B，B 又发出 A

后续步骤

事件指南

了解事件模式和类型安全的事件生成。

了解更多 →

事件 API

探索完整的应用程序和窗口事件 API。

了解更多 →

绑定

使用绑定实现请求/响应。

了解更多 →

窗口事件

处理窗口生命周期事件。

了解更多 →

有疑问？请在Discord中提问，或查看事件示例。

无障碍

编辑此文档

事件系统

事件系统

快速入门

事件类型

自定义事件

系统事件

窗口事件

发出事件

从 Go 发出

从 JavaScript 发出

监听事件

在 Go 中

在 JavaScript 中

系统事件

应用事件

窗口事件

事件钩子

事件模式

发布/订阅模式

请求/响应模式

广播模式

事件聚合

完整示例

最佳实践

✅ 应该做

❌ 不应该做

后续步骤