Add Dropdown

dropdown.go

@@ -0,0 +1,115 @@
+package objects
+
+// import "image"
+import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/input"
+import "git.tebibyte.media/tomo/tomo/event"
+import "git.tebibyte.media/tomo/objects/layouts"
+
+// Dropdown is a non-editable text input that allows the user to pick a value
+// from a list.
+type Dropdown struct {
+	tomo.ContainerBox
+	label *Label
+
+	value string
+	items []string
+	menu  *Menu
+
+	on struct {
+		valueChange event.FuncBroadcaster
+	}
+}
+
+// NewDropdown creates a new dropdown input with the specified items
+func NewDropdown (items ...string) *Dropdown {
+	dropdown := &Dropdown {
+		ContainerBox: tomo.NewContainerBox(),
+		label:        NewLabel(""),
+	}
+	dropdown.SetRole(tomo.R("objects", "Dropdown"))
+	dropdown.SetAttr(tomo.ALayout(layouts.Row { true, false }))
+	dropdown.Add(dropdown.label)
+	// TODO: replace IconValueDecrement with a drop-down expand icon once
+	// we get that
+	dropdown.Add(NewIcon(tomo.IconValueDecrement, tomo.IconSizeSmall))
+	
+	dropdown.SetItems(items...)
+	if len(items) > 0 {
+		dropdown.SetValue(items[0])
+	}
+	
+	dropdown.SetInputMask(true)
+	dropdown.OnButtonDown(dropdown.handleButtonDown)
+	dropdown.OnButtonUp(dropdown.handleButtonUp)
+	dropdown.OnKeyDown(dropdown.handleKeyDown)
+	dropdown.OnKeyUp(dropdown.handleKeyUp)
+	dropdown.SetFocusable(true)
+	return dropdown
+}
+
+// Value returns the value of the dropdown. This does not necissarily have to be
+// in the list of items.
+func (this *Dropdown) Value () string {
+	return this.value
+}
+
+// SetValue sets the value of the dropdown. This does not necissarily have to be
+// in the list of items.
+func (this *Dropdown) SetValue (value string) {
+	this.value = value
+	this.label.SetText(value)
+}
+
+// SetItems sets the items from which the user is able to pick.
+func (this *Dropdown) SetItems (items ...string) {
+	this.items = items
+}
+
+func (this *Dropdown) itemList () []tomo.Object {
+	items := make([]tomo.Object, len(this.items))
+	for index, value := range this.items {
+		value := value
+		item := NewMenuItem(value)
+		item.OnClick(func () {
+			this.SetValue(value)
+			this.on.valueChange.Broadcast()
+		})
+		items[index] = item
+	}
+	return items
+}
+
+func (this *Dropdown) showMenu () {
+	if this.menu != nil {
+		this.menu.Close()
+	}
+	menu, err := NewAnchoredMenu(this, this.itemList()...)
+	if err != nil { return }
+	this.menu = menu
+	menu.SetVisible(true)
+}
+
+func (this *Dropdown) handleKeyDown (key input.Key, numberPad bool) bool {
+	if key != input.KeyEnter && key != input.Key(' ') { return false }
+	return true
+}
+
+func (this *Dropdown) handleKeyUp (key input.Key, numberPad bool) bool {
+	if key != input.KeyEnter && key != input.Key(' ') { return false }
+	this.showMenu()
+	return true
+}
+
+func (this *Dropdown) handleButtonDown (button input.Button) bool {
+	if button != input.ButtonLeft { return false }
+	return true
+}
+
+func (this *Dropdown) handleButtonUp (button input.Button) bool {
+	if button != input.ButtonLeft { return false }
+	if this.Window().MousePosition().In(this.Bounds()) {
+		this.showMenu()
+	}
+	return true
+}