Fix tabbook to default to first non-disabled tab.

Add Initial selected TabBook configuration
Add Initial selected RadioGroup configuration

_examples/demo/page.go

@@ -791,7 +791,10 @@ func radioGroupPage(res *uiResources) *page {
 	for _, cb := range cbs {
 		elements = append(elements, cb)
 	}
-	widget.NewRadioGroup(widget.RadioGroupOpts.Elements(elements...))
+	widget.NewRadioGroup(
+		widget.RadioGroupOpts.Elements(elements...),
+		widget.RadioGroupOpts.InitialElement(elements[2]),
+	)
 
 	return &page{
 		title:   "Radio Group",

_examples/widget_demos/radiogroup/main.go

@@ -157,6 +157,10 @@ func main() {
 		//If you have references to the individual elements you can add them like this since it is a
 		//variadic method.
 		widget.RadioGroupOpts.Elements(button1, button2, button3),
+
+		//This function allows you to select which element should be selected initialially
+		//widget.RadioGroupOpts.InitialElement(button2),
+
 		//This callback method gets called when the Active widget is changed.
 		widget.RadioGroupOpts.ChangedHandler(func(args *widget.RadioGroupChangedEventArgs) {
 			fmt.Println(args.Active.(*widget.Button).Text().Label)

_examples/widget_demos/tabbook/main.go

@@ -23,7 +23,7 @@ func main() {
 	buttonImage, _ := loadButtonImage()
 
 	// load text font
-	face, _ := loadFont(20)
+	face, _ := loadFont(16)
 
 	// construct a new container that serves as the root of the UI hierarchy
 	rootContainer := widget.NewContainer(
@@ -55,7 +55,8 @@ func main() {
 		widget.ContainerOpts.Layout(widget.NewAnchorLayout()),
 	)
 	greenBtn := widget.NewText(
-		widget.TextOpts.Text("Green Tab Button", face, color.Black),
+		widget.TextOpts.Text("Green Tab Button\nThis is configured as the initial tab.", face, color.Black),
+		widget.TextOpts.Position(widget.TextPositionCenter, widget.TextPositionCenter),
 		widget.TextOpts.WidgetOpts(widget.WidgetOpts.LayoutData(widget.AnchorLayoutData{
 			HorizontalPosition: widget.AnchorLayoutPositionCenter,
 			VerticalPosition:   widget.AnchorLayoutPositionCenter,
@@ -84,9 +85,15 @@ func main() {
 		})),
 	)
 	tabBlue.AddChild(blueBtn2)
+
+	tabDisabled := widget.NewTabBookTab("Disabled Tab",
+		widget.ContainerOpts.BackgroundImage(image.NewNineSliceColor(color.NRGBA{R: 80, G: 80, B: 140, A: 255})),
+	)
+	tabDisabled.Disabled = true
+
 	tabBook := widget.NewTabBook(
 		widget.TabBookOpts.TabButtonImage(buttonImage),
-		widget.TabBookOpts.TabButtonText(face, &widget.ButtonTextColor{Idle: color.White}),
+		widget.TabBookOpts.TabButtonText(face, &widget.ButtonTextColor{Idle: color.White, Disabled: color.White}),
 		widget.TabBookOpts.TabButtonSpacing(0),
 		widget.TabBookOpts.ContainerOpts(
 			widget.ContainerOpts.WidgetOpts(widget.WidgetOpts.LayoutData(widget.AnchorLayoutData{
@@ -99,9 +106,10 @@ func main() {
 		),
 		widget.TabBookOpts.TabButtonOpts(
 			widget.ButtonOpts.TextPadding(widget.NewInsetsSimple(5)),
-			widget.ButtonOpts.WidgetOpts(widget.WidgetOpts.MinSize(135, 0)),
+			widget.ButtonOpts.WidgetOpts(widget.WidgetOpts.MinSize(98, 0)),
 		),
-		widget.TabBookOpts.Tabs(tabRed, tabGreen, tabBlue),
+		widget.TabBookOpts.Tabs(tabDisabled, tabRed, tabGreen, tabBlue),
+	//	widget.TabBookOpts.InitialTab(tabGreen),
 	)
 	// add the tabBook as a child of the container
 	rootContainer.AddChild(tabBook)
@@ -153,11 +161,14 @@ func loadButtonImage() (*widget.ButtonImage, error) {
 
 	pressedHover := image.NewNineSliceColor(color.NRGBA{R: 110, G: 110, B: 110, A: 255})
 
+	disabled := image.NewNineSliceColor(color.NRGBA{R: 80, G: 80, B: 140, A: 255})
+
 	return &widget.ButtonImage{
 		Idle:         idle,
 		Hover:        hover,
 		Pressed:      pressed,
 		PressedHover: pressedHover,
+		Disabled:     disabled,
 	}, nil
 }
 

widget/radiogroup.go

@@ -22,6 +22,7 @@ type RadioGroup struct {
 
 	elements  []RadioGroupElement
 	active    RadioGroupElement
+	initial   RadioGroupElement
 	listen    bool
 	doneEvent *event.Event
 }
@@ -81,6 +82,14 @@ func (o RadioGroupOptions) ChangedHandler(f RadioGroupChangedHandlerFunc) RadioG
 	}
 }
 
+// This function allows you to select which element should be selected initialially.
+// Otherwise it will select the first element in the Elements array.
+func (o RadioGroupOptions) InitialElement(e RadioGroupElement) RadioGroupOpt {
+	return func(r *RadioGroup) {
+		r.initial = e
+	}
+}
+
 func (r *RadioGroup) Active() RadioGroupElement {
 	return r.active
 }
@@ -127,7 +136,9 @@ func (r *RadioGroup) create() {
 		})
 	}
 
-	if r.active == nil && len(r.elements) > 0 {
+	if r.initial != nil {
+		r.SetActive(r.initial)
+	} else if len(r.elements) > 0 {
 		r.SetActive(r.elements[0])
 	}
 }

widget/tabbook.go

@@ -27,6 +27,7 @@ type TabBook struct {
 	tabToButton map[*TabBookTab]*Button
 	flipBook    *FlipBook
 	tab         *TabBookTab
+	initialTab  *TabBookTab
 }
 
 type TabBookTab struct {
@@ -137,6 +138,12 @@ func (o TabBookOptions) Tabs(tabs ...*TabBookTab) TabBookOpt {
 	}
 }
 
+func (o TabBookOptions) InitialTab(tab *TabBookTab) TabBookOpt {
+	return func(t *TabBook) {
+		t.initialTab = tab
+	}
+}
+
 func (o TabBookOptions) TabSelectedHandler(f TabBookTabSelectedHandlerFunc) TabBookOpt {
 	return func(t *TabBook) {
 		t.TabSelectedEvent.AddHandler(func(args interface{}) {
@@ -198,7 +205,10 @@ func (t *TabBook) createWidget() {
 		ContainerOpts.Layout(NewRowLayout(
 			RowLayoutOpts.Spacing(t.buttonSpacing))))
 	t.container.AddChild(buttonsContainer)
+
 	btnElements := []RadioGroupElement{}
+	var firstTab *TabBookTab
+
 	for _, tab := range t.tabs {
 		tab := tab
 		btn := NewButton(
@@ -211,10 +221,22 @@ func (t *TabBook) createWidget() {
 		btnElements = append(btnElements, btn)
 		buttonsContainer.AddChild(btn)
 		t.tabToButton[tab] = btn
+		if firstTab == nil {
+			if t.initialTab == nil && !tab.Disabled {
+				firstTab = tab
+			} else if t.initialTab == tab && !tab.Disabled {
+				firstTab = t.initialTab
+			}
+		}
+	}
+	//If we cannot find an initial tab default to to the first one
+	if firstTab == nil {
+		firstTab = t.tabs[0]
 	}
 
 	NewRadioGroup(
 		RadioGroupOpts.Elements(btnElements...),
+		RadioGroupOpts.InitialElement(t.tabToButton[firstTab]),
 		RadioGroupOpts.ChangedHandler(func(args *RadioGroupChangedEventArgs) {
 			tab := args.Active.(*Button).GetWidget().CustomData.(*TabBookTab)
 			t.SetTab(tab)
@@ -228,14 +250,19 @@ func (t *TabBook) createWidget() {
 	t.container.AddChild(t.flipBook)
 	t.flipBookOpts = nil
 
-	t.setTab(t.tabs[0], false)
 }
 
+// Set the current tab for the tab book.
+//
+//		Note: This method should only be called after the
+//	 ui is running. To set the initial tab please use the
+//	 TabBookOptions.InitialTab method during tabbook creation.
 func (t *TabBook) SetTab(tab *TabBookTab) {
-	t.setTab(tab, true)
-}
+	if tab.Disabled {
+		return
+	}
+	t.init.Do()
 
-func (t *TabBook) setTab(tab *TabBookTab, fireEvent bool) {
 	if tab != t.tab {
 		previousTab := t.tab
 
@@ -251,16 +278,16 @@ func (t *TabBook) setTab(tab *TabBookTab, fireEvent bool) {
 			b.SetState(state)
 		}
 
-		if fireEvent {
-			t.TabSelectedEvent.Fire(&TabBookTabSelectedEventArgs{
-				TabBook:     t,
-				Tab:         tab,
-				PreviousTab: previousTab,
-			})
-		}
+		t.TabSelectedEvent.Fire(&TabBookTabSelectedEventArgs{
+			TabBook:     t,
+			Tab:         tab,
+			PreviousTab: previousTab,
+		})
 	}
+
 }
 
+// Return the currently selected tab
 func (t *TabBook) Tab() *TabBookTab {
 	return t.tab
 }