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Widgets

Widgets

The widget package holds every ready-made control in Bellui: buttons, text fields, pickers, navigation bars, lists, tables and more. They follow Material Design 3 (MD3), so most widgets have the MD3 variants as a Style field: filled, tonal, outlined and so on. Colours come from the theme, so every widget follows light and dark mode without extra code.

The gallery's Actions page: filled, tonal, elevated, outlined and text buttons, standard and extended floating action buttons, and four icon button styles The gallery's Actions page: filled, tonal, elevated, outlined and text buttons, standard and extended floating action buttons, and four icon button styles

The gallery app shows most of these widgets in one window. Clone it and run go run . to try them.

Buttons and actions
Button styles, FAB and FAB menu, icon, segmented and split buttons, chips, toolbars.
Text input
Entry and its variants: password, multi-line, numbers, search, completion, rich text.
Selection controls
Check, CheckGroup, RadioGroup, Select, Switch, Slider, RangeSlider, SpinBox.
Pickers
Date, time and date-time pickers and entries, font picker, theme selector.
Navigation
Top app bar, navigation bar, rail and drawer, bottom app bar.
Containment and overlays
Cards, accordions, carousels, sheets, pop-ups, menus and tooltips.
Feedback
Progress bars, activity and loading indicators, badges, snackbars, toasts.
Displaying text
Label, Hyperlink, RichText, Markdown, HTML, TextGrid, icons and separators.
Lists, tables and trees
List, Table, GridWrap, Tree, TreeView and FileTree for large data sets.
Forms
Labelled rows, hints, validation and submit and cancel buttons.

Things every widget shares

Create widgets with their constructor. Every widget has a NewX function, for example widget.NewButton or widget.NewSlider. Set extra fields on the result before you show it. You can also build a widget as a struct literal, such as &widget.Chip{Text: "go", Style: widget.ChipStyleInput}. The constructors call ExtendBaseWidget for you. When you build a widget as a struct literal, call w.ExtendBaseWidget(w) on it before you use its methods.

Change fields, then refresh. Exported fields such as Text, Style or Selected are read when the widget draws. If you change a field after the widget is on screen, call Refresh() so it redraws. Setter methods such as Label.SetText, Button.SetText or ProgressBar.SetValue refresh for you, and their documentation says when they are safe to call from any goroutine. Callbacks such as OnTapped and OnChanged run on the UI thread, so they can update other widgets directly.

Hide, disable and describe. Every widget has Show(), Hide() and Visible(). Most input widgets, such as buttons, entries, check boxes, switches and sliders, also have Disable(), Enable() and Disabled(). Some interactive widgets do not, for example Chip, SegmentedButton, Hyperlink and RichEntry. SetToolTipText adds a hover tooltip to any widget, and SetAccessibilityLabel names a widget that has no visible text, such as an icon button, for screen readers.

Data binding. A few widgets have a NewXWithData constructor that connects them to a value from the data/binding package: Check, Entry, Label, ProgressBar, Select, Slider, List, GridWrap and Tree. All of these except List, GridWrap and Tree also have a Bind method for a widget you already created. Binding is covered in Data binding.

Tabs are containers, not widgets: see container.NewAppTabs and container.NewDocTabs in Layout. Dialogs are in the dialog package.