Added "tabindex" property

propertyNames.go

@@ -690,4 +690,12 @@ const (
 	// "color-dodge" (6), "color-burn" (7), "hard-light" (8), "soft-light" (9), "difference" (10),
 	// "exclusion" (11), "hue" (12), "saturation" (13), "color" (14), "luminosity" (15).
 	MixBlendMode = "mix-blend-mode"
+
+	// TabIndex is the constant for the "tabindex" property tag.
+	// The "tabindex" int property indicates that View can be focused, and where it participates in sequential keyboard navigation
+	// (usually with the Tab key, hence the name).
+	// * A negative value means that View is not reachable via sequential keyboard navigation, but could be focused by clicking with the mouse or touching.
+	// * tabindex="0" means that View should be focusable in sequential keyboard navigation, after any positive tabindex values and its order is defined in order of its addition.
+	// * A positive value means View should be focusable in sequential keyboard navigation, with its order defined by the value of the number.
+	TabIndex = "tabindex"
 )

propertySet.go

@@ -74,6 +74,7 @@ var intProperties = []string{
 	ColumnSpan,
 	ColumnCount,
 	Order,
+	TabIndex,
 }
 
 var floatProperties = map[string]struct{ min, max float64 }{

tableView.go

@@ -606,7 +606,8 @@ func (table *tableViewData) propertyChanged(tag string) {
 
 			switch GetTableSelectionMode(table) {
 			case CellSelection:
-				session.updateProperty(htmlID, "tabindex", "0")
+				tabIndex, _ := intProperty(table, TabIndex, session, 0)
+				session.updateProperty(htmlID, "tabindex", tabIndex)
 				session.updateProperty(htmlID, "onfocus", "tableViewFocusEvent(this, event)")
 				session.updateProperty(htmlID, "onblur", "tableViewBlurEvent(this, event)")
 				session.updateProperty(htmlID, "data-selection", "cell")
@@ -621,7 +622,8 @@ func (table *tableViewData) propertyChanged(tag string) {
 				session.updateProperty(htmlID, "onkeydown", "tableViewCellKeyDownEvent(this, event)")
 
 			case RowSelection:
-				session.updateProperty(htmlID, "tabindex", "0")
+				tabIndex, _ := intProperty(table, TabIndex, session, 0)
+				session.updateProperty(htmlID, "tabindex", tabIndex)
 				session.updateProperty(htmlID, "onfocus", "tableViewFocusEvent(this, event)")
 				session.updateProperty(htmlID, "onblur", "tableViewBlurEvent(this, event)")
 				session.updateProperty(htmlID, "data-selection", "row")
@@ -636,7 +638,11 @@ func (table *tableViewData) propertyChanged(tag string) {
 				session.updateProperty(htmlID, "onkeydown", "tableViewRowKeyDownEvent(this, event)")
 
 			default: // NoneSelection
-				for _, prop := range []string{"tabindex", "data-current", "onfocus", "onblur", "onkeydown", "data-selection"} {
+				if tabIndex, ok := intProperty(table, TabIndex, session, -1); !ok || tabIndex < 0 {
+					session.removeProperty(htmlID, "tabindex")
+				}
+
+				for _, prop := range []string{"data-current", "onfocus", "onblur", "onkeydown", "data-selection"} {
 					session.removeProperty(htmlID, prop)
 				}
 			}

view.go

@@ -187,6 +187,14 @@ func (view *viewData) remove(tag string) {
 	case ID:
 		view.viewID = ""
 
+	case TabIndex, "tab-index":
+		delete(view.properties, tag)
+		if view.Focusable() {
+			view.session.updateProperty(view.htmlID(), "tabindex", "0")
+		} else {
+			view.session.updateProperty(view.htmlID(), "tabindex", "-1")
+		}
+
 	case UserData:
 		delete(view.properties, tag)
 
@@ -312,6 +320,18 @@ func (view *viewData) set(tag string, value any) bool {
 		}
 		view.viewID = text
 
+	case TabIndex, "tab-index":
+		if !view.setIntProperty(tag, value) {
+			return false
+		}
+		if value, ok := intProperty(view, TabIndex, view.Session(), 0); ok {
+			view.session.updateProperty(view.htmlID(), "tabindex", strconv.Itoa(value))
+		} else if view.Focusable() {
+			view.session.updateProperty(view.htmlID(), "tabindex", "0")
+		} else {
+			view.session.updateProperty(view.htmlID(), "tabindex", "-1")
+		}
+
 	case UserData:
 		view.properties[tag] = value
 
@@ -758,8 +778,14 @@ func viewHTML(view View, buffer *strings.Builder) {
 		buffer.WriteRune(' ')
 	}
 
-	if view.Focusable() && !disabled {
+	if !disabled {
-		buffer.WriteString(`tabindex="0" `)
+		if value, ok := intProperty(view, TabIndex, view.Session(), -1); ok {
+			buffer.WriteString(`tabindex="`)
+			buffer.WriteString(strconv.Itoa(value))
+			buffer.WriteString(`" `)
+		} else if view.Focusable() {
+			buffer.WriteString(`tabindex="0" `)
+		}
 	}
 
 	buffer.WriteString(`onscroll="scrollEvent(this, event)" `)

viewUtils.go

@@ -153,6 +153,25 @@ func GetOverflow(view View, subviewID ...string) int {
 	return enumStyledProperty(view, subviewID, Overflow, defaultOverflow, false)
 }
 
+// GetTabIndex returns the subview tab-index.
+// If the second argument (subviewID) is not specified or it is "" then a tab-index of the first argument (view) is returned
+func GetTabIndex(view View, subviewID ...string) int {
+	if len(subviewID) > 0 && subviewID[0] != "" {
+		view = ViewByID(view, subviewID[0])
+	}
+
+	defaultValue := -1
+	if view != nil {
+		if view.Focusable() {
+			defaultValue = 0
+		}
+		if value, ok := intProperty(view, TabIndex, view.Session(), defaultValue); ok {
+			return value
+		}
+	}
+	return defaultValue
+}
+
 // GetZIndex returns the subview z-order.
 // If the second argument (subviewID) is not specified or it is "" then a z-order of the first argument (view) is returned
 func GetZIndex(view View, subviewID ...string) int {