Method Insert

widgetlist.go:101–123

(index int, item Widget)

}

func (l *WidgetList) Insert(index int, item Widget) error {
	if l.Contains(item) {
		return newError("cannot insert same widget multiple times")
	}

	observer := l.observer
	if observer != nil {
		if err := observer.onInsertingWidget(index, item); err != nil {
			return err
		}
	}

	l.insertIntoSlice(index, item)

	if observer != nil {
		if err := observer.onInsertedWidget(index, item); err != nil {
			l.items = append(l.items[:index], l.items[index+1:]...)
			return err
		}
	}

	return nil
}

func (l *WidgetList) Len() int {
	return len(l.items)