kotlin-native-gtk3

Main.kt

import kotlinx.cinterop.*
import gtk3.*

// Note that all callback parameters must be primitive types or nullable C pointers.
fun <F : CFunction<*>> g_signal_connect(obj: CPointer<*>, actionName: String,
        action: CPointer<F>, data: gpointer? = null, connect_flags: GConnectFlags = 0u) {
    g_signal_connect_data(obj.reinterpret(), actionName, action.reinterpret(),
            data = data, destroy_data = null, connect_flags = connect_flags)

}

abstract class Button(val id: String) {
    val ref = StableRef.create(this)

    abstract fun clicked()

    fun dispose() {
        ref.dispose()
    }
}

class Builder {
    val gtkBuilder = gtk_builder_new()

    constructor(xml: String) {
        gtk_builder_add_from_string(gtkBuilder, xml, xml.length.toULong(), null)
    }

    fun connect(button: Button) {
        val buttonWidget = gtk_builder_get_object(gtkBuilder, button.id)!!
        g_signal_connect(buttonWidget, "clicked",
                staticCFunction { _: CPointer<GtkWidget>?, data: gpointer? ->
                    data!!.asStableRef<Button>().get().clicked()
                }, button.ref.asCPointer())
    }
}

fun main(args: Array<String>) {
    val xml = "<interface>" +
            "  <object class=\"GtkWindow\" id=\"main-window\">" +
            "    <child>" +
            "      <object class=\"GtkVBox\" id=\"vbox-layout\">" +
            "        <property name=\"homogeneous\">FALSE</property>" +
            "        <child>" +
            "          <object class=\"GtkButton\" id=\"first-button\">" +
            "            <property name=\"label\">First button!</property>" +
            "          </object>" +
            "        </child>" +
            "        <child>" +
            "          <object class=\"GtkButton\" id=\"second-button\">" +
            "            <property name=\"label\">Second button!</property>" +
            "          </object>" +
            "        </child>" +
            "      </object>" +
            "    </child>" +
            "  </object>" +
            "</interface>"

    gtk_init(cValuesOf(0), null)

    val builder = Builder(xml)
    val window = gtk_builder_get_object(builder.gtkBuilder, "main-window")!!.reinterpret<GtkWidget>()

    g_signal_connect(window, "destroy", staticCFunction { _: CPointer<GtkWidget>?, _: gpointer? ->
        println("Window closed")
        gtk_main_quit()
    }, null)

    val firstButton = object : Button("first-button") {
        override fun clicked() {
            println("First Button clicked")
        }
    }
    builder.connect(firstButton)
    val secondButton = object : Button("second-button") {
        override fun clicked() {
            println("Second Button clicked")
        }
    }
    builder.connect(secondButton)

    gtk_widget_show_all(window)
    gtk_main()

    println("Main finished")
    firstButton.dispose()
    secondButton.dispose()
}