#248 Adding tab for next input field

src/markup/document/html_parser.go

@@ -92,6 +92,9 @@ type Document struct {
 	tagElements   map[string][]*Element
 	style         rules.StyleSheet
 	stylizer      func(rules.StyleSheet, *Document, *engine.Host)
+	// TODO:  Should this be here?
+	firstInput *ui.Input
+	lastInput  *ui.Input
 }
 
 func (d *Document) SetupStylizer(style rules.StyleSheet, host *engine.Host,
@@ -205,6 +208,14 @@ func (d *Document) createUIElement(host *engine.Host, e *Element, parent *ui.Pan
 				input := panel.ConvertToInput(e.Attribute("placeholder"))
 				input.SetText(e.Attribute("value"))
 				uiElm = input
+				if d.firstInput == nil {
+					d.firstInput = input
+				}
+				if d.lastInput != nil {
+					d.lastInput.SetNextFocusedInput(input)
+				}
+				d.lastInput = input
+				input.SetNextFocusedInput(d.firstInput)
 			}
 		}
 		entry := appendElement(uiElm, panel)

src/ui/input.go

@@ -81,6 +81,7 @@ type localInputData struct {
 	selectStart, selectEnd, dragStart int
 	inputType                         InputType
 	isActive                          bool
+	nextFocusInput                    *Input
 }
 
 type Input Panel
@@ -89,6 +90,10 @@ func (input *Input) Data() *localInputData {
 	return input.localData.(*localInputData)
 }
 
+func (input *Input) SetNextFocusedInput(next *Input) {
+	input.Data().nextFocusInput = next
+}
+
 func (p *Panel) ConvertToInput(placeholderText string) *Input {
 	input := (*Input)(p)
 	host := p.Host()
@@ -582,10 +587,16 @@ func (input *Input) keyPressed(keyId int, keyState hid.KeyState) {
 					fallthrough
 				case hid.KeyboardKeyEnter:
 					input.submit()
+				case hid.KeyboardKeyTab:
+					// Delay a frame so we don't hit a loop of going to next
+					input.host.RunAfterFrames(1, func() {
+						next := input.Data().nextFocusInput
+						if next != nil {
+							next.Select()
+						}
+					})
 				}
 			}
-		}
-		if keyState == hid.KeyStateDown {
 			input.requestEvent(EventTypeKeyDown)
 		} else if keyState == hid.KeyStateUp {
 			input.requestEvent(EventTypeKeyUp)