Concurrent window changing

multiwindow.go

package main

import (
	"fmt"
	"github.com/lxn/walk"
	. "github.com/lxn/walk/declarative"
	"time"
)

var mainWindow *walk.MainWindow

func main() {
	_, err := MainWindow{
		AssignTo: &mainWindow,
		Title:    "Main Window",
		MinSize:  Size{400, 300},
		Layout:   VBox{},
		Children: []Widget{
			Label{Text: "something in main window"},
			PushButton{
				Text: "Do progress",
				OnClicked: func() {
					go askDialog()
				},
			},
		},
	}.Run()
	if err != nil {
		fmt.Println(err)
	}
}
func askDialog() {
	var dialog *walk.Dialog
	var acceptPB, cancelPB *walk.PushButton
	_, err := Dialog{
		AssignTo:      &dialog,
		Title:         "Do you want some progress?",
		DefaultButton: &acceptPB,
		CancelButton:  &cancelPB,
		MinSize:       Size{300, 100},
		Layout:        HBox{},
		Children: []Widget{
			PushButton{
				AssignTo: &acceptPB,
				Text:     "Yes",
				OnClicked: func() {
					dialog.Accept()
					go doProgress()
				},
			},
			PushButton{
				AssignTo:  &cancelPB,
				Text:      "No",
				OnClicked: func() { dialog.Cancel() },
			},
		},
	}.Run(mainWindow)
	if err != nil {
		fmt.Println(err)
	}
}
func doProgress() {
	var dialog *walk.Dialog
	var progressBar *walk.ProgressBar
	err := Dialog{
		AssignTo: &dialog,
		Title:    "Progress dialog",
		MinSize:  Size{300, 200},
		Layout:   VBox{},
		Children: []Widget{
			ProgressBar{AssignTo: &progressBar},
		},
	}.Create(mainWindow)
	if err != nil {
		fmt.Println(err)
		return
	}
	dialog.Starting().Attach(func() {
		go progressWorker(dialog, progressBar)
	})
	dialog.Run()
}
func progressWorker(dialog *walk.Dialog, progressBar *walk.ProgressBar) {
	defer dialog.Synchronize(func() {
		dialog.Close(0)
	})
	time.Sleep(1 * time.Millisecond) // waiting for some external event
	n := 1234                        // changes
	dialog.Synchronize(func() {
		progressBar.SetRange(0, n)
	})
	for i := 0; i < n; i += 10 {
		time.Sleep(1 * time.Millisecond) // event
		fmt.Println("progress", i)
		dialog.Synchronize(func() {
			progressBar.SetValue(i)
		})
	}
}