objects/dropdown.go

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
}