Golang : Qt progress dialog example
Found a need to show progress indication while developing a Qt application recently. Below is a simple example of how to invoke the Qt ProgressDialog in Golang with Qt-binding.
What it does is to launch a GUI application with a button to press. Upon pressing the button, you will see a progress dialog box in action and show the text update on your terminal screen.
Please follow the setup instruction for Golang-Qt bindings at https://github.com/therecipe/qt
Tips: Dump out the documentation to text files for easier search and viewing.
$godoc github.com/therecipe/qt/widgets > widgets.txt
$godoc github.com/therecipe/qt/gui > gui.txt
$godoc github.com/therecipe/qt/core > core.txt
Here you go!
package main
import (
"fmt"
"github.com/therecipe/qt/core"
"github.com/therecipe/qt/widgets"
"os"
"time"
)
var (
mainApp *widgets.QApplication
progressDialog *widgets.QProgressDialog
mainLayout *widgets.QWidget
)
func delaySecond(n time.Duration) {
time.Sleep(n * time.Second)
}
func populate() *widgets.QWidget {
mainLayout = widgets.NewQWidget(nil, 0)
button := widgets.NewQPushButton2("Show Progress Dialog", nil)
button.ConnectClicked(func(flag bool) {
jobs := 100
progressDialog := widgets.NewQProgressDialog(mainLayout, core.Qt__Widget)
progressDialog.SetWindowModality(core.Qt__NonModal)
progressDialog.SetWindowTitle("Progress bar progressing...")
progressDialog.SetMinimum(0)
progressDialog.SetMaximum(jobs)
progressDialog.Show()
for i := 1; i < jobs; i++ {
progressDialog.SetValue(i)
// see http://stackoverflow.com/questions/8399349/simple-example-using-qprogressdialog-any-ideas-why-this-doesnt-work-properly
// on the QApplication::processEvents()
// somehow ExcludeUserInputEvents will prevent us from clicking the Cancel button!
//core.QCoreApplication_ProcessEvents(core.QEventLoop__ExcludeUserInputEvents)
// without this line, the progress bar or UI elements will not be updated!!
core.QCoreApplication_ProcessEvents(core.QEventLoop__AllEvents)
// too fast! introduce some delay to let you see the progression
delaySecond(time.Duration(1))
if progressDialog.WasCanceled() {
fmt.Printf("\r")
fmt.Printf("\rAborted at %d/%d", i, jobs)
break
}
// too lazy to add text label in the widget
// so, we use https://www.socketloop.com/tutorials/golang-overwrite-previous-output-with-count-down-timer
fmt.Printf("\rProgressing %d/%d", progressDialog.Value(), jobs)
}
progressDialog.SetValue(jobs)
})
layout := widgets.NewQVBoxLayout()
layout.AddWidget(button, 0, core.Qt__AlignCenter)
mainLayout.SetLayout(layout)
return mainLayout
}
func main() {
mainApp = widgets.NewQApplication(len(os.Args), os.Args)
populate().Show()
mainApp.Exec()
}
References:
http://www.bogotobogo.com/Qt/Qt5QProgressDialogModalModelessQTimer.php
http://doc.qt.io/qt-5/qprogressdialog.html
http://stackoverflow.com/questions/25966730/how-can-i-add-a-progress-bar-in-splash-screen-pyqt4
See also : Golang : Qt splash screen with delay example
By Adam Ng
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