package main

import (
    "github.com/gotk3/gotk3/gtk"
    "log"
)

func main() {
    // Initialize GTK without parsing any command line arguments.
    gtk.Init(nil)

    // Create a new toplevel window, set its title, and connect it to the
    // "destroy" signal to exit the GTK main loop when it is destroyed.
    win, err := gtk.WindowNew(gtk.WINDOW_TOPLEVEL)
    if err != nil {
        log.Fatal("Unable to create window:", err)
    }
    win.SetTitle("Simple Example")
    win.Connect("destroy", func() {
        gtk.MainQuit()
    })

    // Create a new label widget to show in the window.
    l, err := gtk.LabelNew("Hello, gotk3!")
    if err != nil {
        log.Fatal("Unable to create label:", err)
    }

    // Add the label to the window.
    win.Add(l)

    // Set the default window size.
    win.SetDefaultSize(800, 600)

    // Recursively show all widgets contained in this window.
    win.ShowAll()

    // Begin executing the GTK main loop.  This blocks until
    // gtk.MainQuit() is run.
    gtk.Main()
}

package main

import (
    "log"
    "os"

    "github.com/gotk3/gotk3/glib"
    "github.com/gotk3/gotk3/gtk"
)

// Simple Gtk3 Application written in go.
// This application creates a window on the application callback activate.
// More GtkApplication info can be found here -> https://wiki.gnome.org/HowDoI/GtkApplication

func main() {
    // Create Gtk Application, change appID to your application domain name reversed.
    const appID = "org.gtk.example"
    application, err := gtk.ApplicationNew(appID, glib.APPLICATION_FLAGS_NONE)
    // Check to make sure no errors when creating Gtk Application
    if err != nil {
        log.Fatal("Could not create application.", err)
    }
    // Application signals available
    // startup -> sets up the application when it first starts
    // activate -> shows the default first window of the application (like a new document). This corresponds to the application being launched by the desktop environment.
    // open -> opens files and shows them in a new window. This corresponds to someone trying to open a document (or documents) using the application from the file browser, or similar.
    // shutdown ->  performs shutdown tasks
    // Setup Gtk Application callback signals
    application.Connect("activate", func() { onActivate(application) })
    // Run Gtk application
    os.Exit(application.Run(os.Args))
}

// Callback signal from Gtk Application
func onActivate(application *gtk.Application) {
    // Create ApplicationWindow
    appWindow, err := gtk.ApplicationWindowNew(application)
    if err != nil {
        log.Fatal("Could not create application window.", err)
    }
    // Set ApplicationWindow Properties
    appWindow.SetTitle("Basic Application.")
    appWindow.SetDefaultSize(400, 400)
    appWindow.Show()
}

package main

import (
    "log"
    "os"

    "github.com/gotk3/gotk3/glib"
    "github.com/gotk3/gotk3/gtk"
)

// Simple Gtk3 Application written in go.
// This application creates a window on the application callback activate.
// More GtkApplication info can be found here -> https://wiki.gnome.org/HowDoI/GtkApplication

func main() {
    // Create Gtk Application, change appID to your application domain name reversed.
    const appID = "org.gtk.example"
    application, err := gtk.ApplicationNew(appID, glib.APPLICATION_FLAGS_NONE)
    // Check to make sure no errors when creating Gtk Application
    if err != nil {
        log.Fatal("Could not create application.", err)
    }

    // Application signals available
    // startup -> sets up the application when it first starts
    // activate -> shows the default first window of the application (like a new document). This corresponds to the application being launched by the desktop environment.
    // open -> opens files and shows them in a new window. This corresponds to someone trying to open a document (or documents) using the application from the file browser, or similar.
    // shutdown ->  performs shutdown tasks
    // Setup activate signal with a closure function.
    application.Connect("activate", func() {
        // Create ApplicationWindow
        appWindow, err := gtk.ApplicationWindowNew(application)
        if err != nil {
            log.Fatal("Could not create application window.", err)
        }
        // Set ApplicationWindow Properties
        appWindow.SetTitle("Basic Application.")
        appWindow.SetDefaultSize(400, 400)
        appWindow.Show()
    })
    // Run Gtk application
    application.Run(os.Args)
}