Add navigation components 131-150; pixel Pad, Finish, Park, Since

navigation/dropdown.go

@@ -0,0 +1,49 @@
+package navigation
+
+import (
+	"log/slog"
+
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/input"
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+type DropdownMenuOptions struct {
+	Disabled bool
+}
+
+type DropdownMenuResult struct {
+	Element *ui.Element
+	// Chosen is the item taken this frame, or -1.
+	Chosen int
+}
+
+// DropdownMenu is a button opening a menu of items.
+func DropdownMenu(c *ui.Context, text string, items []MenuItem, o DropdownMenuOptions) DropdownMenuResult {
+	off := o.Disabled || pixel.Current(c).Inert
+	b := input.Button(c, text+" ▼", input.ButtonOptions{Label: text, Disabled: o.Disabled})
+	m := ui.Local(b.Element, menuKey{}, func() menu { return menu{lit: -1} })
+	if off {
+		// Closing on disable must not return focus to it.
+		if m.open {
+			c.Root().Focus()
+		}
+		m.open = false
+	}
+	res := DropdownMenuResult{Element: b.Element, Chosen: -1}
+	switch {
+	case b.Clicked && m.open:
+		m.open = false
+	case b.Clicked, !m.open && !off && b.Element.Shortcut(0, ui.KeyDown):
+		m.show(items)
+	}
+	res.Chosen = m.keys(b.Element.Shortcut, items)
+	if _, clicked := m.list(c, b.Element, items); clicked >= 0 {
+		res.Chosen = clicked
+	}
+	if res.Chosen >= 0 {
+		slog.Debug("8bit: dropdown", "label", text, "item", items[res.Chosen].Label)
+	}
+	return res
+}