Feedback

Feedback widgets tell the user that something is happening, has happened or needs attention. None of them takes input, apart from the optional action button on a snackbar.

Which one to use

Progress

download := widget.NewProgressBar()
download.TextFormatter = func() string {
	return fmt.Sprintf("%.0f of 100 MB", download.Value*100)
}
go func() {
	for i := 0; i <= 100; i++ {
		time.Sleep(50 * time.Millisecond)
		download.SetValue(float64(i) / 100) // safe from any goroutine
	}
}()

waiting := widget.NewProgressBarInfinite()
stop := widget.NewButton("Stop", waiting.Stop)

ProgressBar fills from Min to Max, which are 0 and 1 by default, and shows the value as a percentage. TextFormatter replaces that text with your own. SetValue is safe to call from any goroutine, so a background task can report progress directly. NewProgressBarWithData connects the value to a binding.Float.

ProgressBarInfinite loops for as long as it runs. Stop() stops the animation, Start() starts it again and Running() reports which.

Activity and loading placeholders

spinner := widget.NewActivity()
spinner.Start()

avatar := widget.NewLoadingIndicator(widget.LoadingShapeCircle)
line := widget.NewLoadingIndicator(widget.LoadingShapeText)

Activity is a small animated busy indicator. Call Start() to animate it and Stop() when the work is done.

LoadingIndicator is a shimmering placeholder in the shape of the content to come: LoadingShapeRect for cards and images, LoadingShapeCircle for avatars and LoadingShapeText for lines of text. Swap it for the real content when it arrives.

Badge

Badge attaches a small indicator to another widget, usually an icon button. NewBadge shows a dot. NewBadgeWithCount shows a number; counts above 999 show as “999+”. Change Count and call Refresh() to update it, and set it to 0 for a dot.

inbox := widget.NewBadgeWithCount(widget.NewIconButton(theme.MailComposeIcon(), nil), 3)
updates := widget.NewBadge(widget.NewIconButton(theme.DownloadIcon(), nil))

Snackbar

A Snackbar is a short message at the bottom of the window, with an optional action button. It closes by itself after Duration (4 seconds by default), or when the user taps the action. Taps elsewhere do not close it.

archive := widget.NewButton("Archive", func() {
	removed := items
	items = nil
	list.SetText("(empty)")
	widget.ShowSnackbar("2 files archived", "Undo", func() {
		items = removed
		list.SetText("a.txt, b.txt")
	}, w.Canvas())
})

ShowSnackbar(text, actionText, action, canvas) creates and shows one. Pass an empty actionText for a message without a button. To change Duration first, create it with NewSnackbar, set the field and call Show(canvas). Hide() closes it early and is safe from any goroutine.

Toast

A Toast is a brief notice near the bottom of the window. It closes after 3 seconds and does not block input: taps go through to whatever is underneath.

save := widget.NewButton("Save", func() {
	widget.ShowToastWithImportance("Saved", widget.SuccessImportance, w.Canvas())
})

ShowToast uses neutral colours. ShowToastWithImportance takes DangerImportance, WarningImportance or SuccessImportance for the theme’s error, warning and success colours. Both return the Toast, so you can call Dismiss() to close it early.

Both snackbars and toasts are read out by screen readers when they appear. Danger and warning toasts interrupt what the screen reader is saying; the others wait their turn.