Windows tray menus (#2181)

* Add example

* Add windows systray

* Add gitkeep

* use windows.GUID

v2/pkg/application/application.go

@@ -1,10 +1,12 @@
 package application
 
 import (
+	"context"
 	"github.com/wailsapp/wails/v2/internal/app"
 	"github.com/wailsapp/wails/v2/internal/signal"
 	"github.com/wailsapp/wails/v2/pkg/menu"
 	"github.com/wailsapp/wails/v2/pkg/options"
+	"sync"
 )
 
 // Application is the main Wails application
@@ -12,8 +14,13 @@ type Application struct {
 	application *app.App
 	options     *options.App
 
+	// System Trays
+	systemTrays []*SystemTray
+
 	// running flag
 	running bool
+
+	shutdown sync.Once
 }
 
 // NewWithOptions creates a new Application with the given options
@@ -46,6 +53,10 @@ func (a *Application) SetApplicationMenu(appMenu *menu.Menu) {
 // Run starts the application
 func (a *Application) Run() error {
 
+	for _, systemtray := range a.systemTrays {
+		go systemtray.run()
+	}
+
 	err := applicationInit()
 	if err != nil {
 		return err
@@ -66,10 +77,44 @@ func (a *Application) Run() error {
 
 	a.running = true
 
-	return a.application.Run()
+	err = a.application.Run()
+	a.Quit()
+	return err
 }
 
 // Quit will shut down the application
 func (a *Application) Quit() {
-	a.application.Shutdown()
+	a.shutdown.Do(func() {
+		for _, systray := range a.systemTrays {
+			systray.Close()
+		}
+		a.application.Shutdown()
+	})
+}
+
+// Bind the given struct to the application
+func (a *Application) Bind(boundStruct any) {
+	a.options.Bind = append(a.options.Bind, boundStruct)
+}
+
+func (a *Application) On(eventType EventType, callback func()) {
+
+	c := func(ctx context.Context) {
+		callback()
+	}
+
+	switch eventType {
+	case StartUp:
+		a.options.OnStartup = c
+	case ShutDown:
+		a.options.OnShutdown = c
+	case DomReady:
+		a.options.OnDomReady = c
+	}
+}
+
+func (a *Application) NewSystemTray(options *options.SystemTray) *SystemTray {
+	systemTray := newSystemTray(options)
+	a.systemTrays = append(a.systemTrays, systemTray)
+	return systemTray
 }