internal void InitTabs()
{
Items.Clear();
if (ItemsDataSource != null)
{
foreach (var item in ItemsDataSource)
{
var newitem = new TabItem();
if (TabItemTemplate != null)
{
newitem.Content = TabItemTemplate.LoadContent();
}
if (TabHeaderItemTemplate != null)
{
newitem.Header = TabHeaderItemTemplate.LoadContent();
}
newitem.DataContext = item;
Items.Add(newitem);
}
}
}
private void AddTabToView(TabItem tab)
{
var tabSize = (TabSizeOption.IsAbsolute && TabSizeOption.Value.Equals(0)) ? new GridLength(1, GridUnitType.Star) : TabSizeOption;
_headerContainerGrid.ColumnDefinitions.Add(new ColumnDefinition {
Width = tabSize
});
tab.IsCurrent = _headerContainerGrid.ColumnDefinitions.Count - 1 == SelectedTabIndex;
var headerIcon = new Image
{
Margin = new Thickness(0, 8, 0, 0),
BindingContext = tab,
HorizontalOptions = LayoutOptions.CenterAndExpand,
VerticalOptions = LayoutOptions.Center,
WidthRequest = tab.HeaderIconSize,
HeightRequest = tab.HeaderIconSize
};
headerIcon.SetBinding(Image.SourceProperty, nameof(TabItem.HeaderIcon));
headerIcon.SetBinding(IsVisibleProperty, nameof(TabItem.HeaderIcon), converter: new NullToBoolConverter());
var headerLabel = new Label
{
BindingContext = tab,
VerticalTextAlignment = TextAlignment.Center,
HorizontalTextAlignment = TextAlignment.Center,
HorizontalOptions = LayoutOptions.Center,
VerticalOptions = LayoutOptions.CenterAndExpand,
Margin = new Thickness(5, 8, 5, 5)
};
headerLabel.SetBinding(Label.TextProperty, nameof(TabItem.HeaderText));
headerLabel.SetBinding(Label.TextColorProperty, nameof(TabItem.HeaderTextColor));
headerLabel.SetBinding(Label.FontSizeProperty, nameof(TabItem.HeaderTabTextFontSize));
headerLabel.SetBinding(Label.FontFamilyProperty, nameof(TabItem.HeaderTabTextFontFamily));
headerLabel.SetBinding(Label.FontAttributesProperty, nameof(TabItem.HeaderTabTextFontAttributes));
headerLabel.SetBinding(IsVisibleProperty, nameof(TabItem.HeaderText), converter: new NullToBoolConverter());
var selectionBarBoxView = new BoxView
{
VerticalOptions = LayoutOptions.End,
BindingContext = tab,
HeightRequest = HeaderSelectionUnderlineThickness,
WidthRequest = HeaderSelectionUnderlineWidth
};
//selectionBarBoxView.SetBinding(IsVisibleProperty, nameof(TabItem.IsCurrent));
var underlineColorBinding = new Binding(nameof(TabItem.IsCurrent), BindingMode.OneWay, new SelectedTabHeaderToTabBackgroundColorConverter(), this);
//selectionBarBoxView.SetBinding(BoxView.ColorProperty, nameof(TabItem.HeaderSelectionUnderlineColor), BindingMode.OneWay, new SelectedTabHeaderToTabBackgroundColorConverter(), );
selectionBarBoxView.SetBinding(BoxView.BackgroundColorProperty, underlineColorBinding);
selectionBarBoxView.SetBinding(WidthRequestProperty, nameof(TabItem.HeaderSelectionUnderlineWidth));
selectionBarBoxView.SetBinding(HeightRequestProperty, nameof(TabItem.HeaderSelectionUnderlineThickness));
selectionBarBoxView.SetBinding(HorizontalOptionsProperty,
nameof(TabItem.HeaderSelectionUnderlineWidth),
converter: new DoubleToLayoutOptionsConverter());
selectionBarBoxView.PropertyChanged += (object sender, PropertyChangedEventArgs e) =>
{
if (e.PropertyName == nameof(TabItem.IsCurrent))
{
SetPosition(ItemSource.IndexOf((TabItem)((BoxView)sender).BindingContext));
}
if (e.PropertyName == nameof(WidthRequest))
{
selectionBarBoxView.HorizontalOptions = tab.HeaderSelectionUnderlineWidth > 0 ? LayoutOptions.CenterAndExpand : LayoutOptions.FillAndExpand;
}
};
View headerItemView;
if (TabHeaderItemTemplate != null)
{
headerItemView = (View)TabHeaderItemTemplate.CreateContent();
headerItemView.BindingContext = tab;
}
else
{
headerItemView = new StackLayout
{
VerticalOptions = LayoutOptions.FillAndExpand,
Children = { headerIcon, headerLabel, selectionBarBoxView },
BackgroundColor = HeaderBackgroundColor
};
}
var tapRecognizer = new TapGestureRecognizer();
tapRecognizer.Tapped += (object s, EventArgs e) =>
{
_supressCarouselViewPositionChangedEvent = true;
var capturedIndex = _headerContainerGrid.Children.IndexOf((View)s);
SetPosition(capturedIndex);
_supressCarouselViewPositionChangedEvent = false;
};
headerItemView.GestureRecognizers.Add(tapRecognizer);
_headerContainerGrid.Children.Add(headerItemView, _headerContainerGrid.ColumnDefinitions.Count - 1, 0);
_carouselView.ItemsSource = ItemSource.Select(t => t.Content);
}
void ItemsDataSource_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
{
if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add)
{
if (e.NewStartingIndex > -1)
{
foreach (var item in e.NewItems)
{
var newitem = new TabItem();
if (TabItemTemplate != null)
{
newitem.Content = TabItemTemplate.LoadContent();
}
if (TabHeaderItemTemplate != null)
{
newitem.Header = TabHeaderItemTemplate.LoadContent();
}
newitem.DataContext = item;
Items.Add(newitem);
this.SelectedItem = newitem;
}
}
}
else if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Remove)
{
if (e.OldStartingIndex > -1)
{
Items.RemoveAt(e.OldStartingIndex);
}
}
else if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Replace)
{
Items.RemoveAt(e.OldStartingIndex);
var newitem = new TabItem();
if (TabItemTemplate != null)
{
newitem.Content = TabItemTemplate.LoadContent();
}
if (TabHeaderItemTemplate != null)
{
newitem.Header = TabHeaderItemTemplate.LoadContent();
}
newitem.DataContext = e.NewItems[0];
Items.Add(newitem);
Items.Insert(e.NewStartingIndex, newitem);
}
else if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Reset)
{
InitTabs();
}
}