TabView

TabView is a component that allows you to switch between different views by selecting a tab on MAUI. Tabs and tab contents can be difined as DataTemplate.

Usage

TabView is a Control that takes a TabViewItems collection to render tabs and tab contents. The TabViewItems collection is a collection of TabViewItem objects. Each TabViewItem object has Title, Data, Content and ContentTemplate properties. The Title property is a string that is used to render the tab. The Data property is an object that can be used to bind data to the tab header view. Both Content and ContentTemplate is used to render content of the tab. The ContentTemplate property is a DataTemplate that is used to render the tab content lazy. It's performance friendly when you have a lot of tabs. The content isn't created until user hit the tab. Content property is opposite of ContentTempalte. You can directly create and set the content of the tab. The Content property is a View that is used to render the tab content immediately. The Content property is not lazy. It's created when the TabView is created. The Content property is useful when you have a small number of tabs or your tab content is too complex and creating when hitting the tab is not a good idea.

TabView is defined in UraniumUI.Material.Controls namespace. You can add it to your XAML like this:

xmlns:material="http://schemas.enisn-projects.io/dotnet/maui/uraniumui/material"

Then you can use it like this:

<material:TabView>
    
    <material:TabItem Title="Tab One">
        <material:TabItem.ContentTemplate>
            <DataTemplate>
                    <Label Text="First Tab" />
            </DataTemplate>
        </material:TabItem.ContentTemplate>
    </material:TabItem>


    <material:TabItem Title="Tab Two">
        <material:TabItem.ContentTemplate>
            <DataTemplate>
                    <Label Text="Second Tab" />
            </DataTemplate>
        </material:TabItem.ContentTemplate>
    </material:TabItem>

    <material:TabItem Title="Tab Three">
        <material:TabItem.ContentTemplate>
            <DataTemplate>
                    <Label Text="Third Tab" />
            </DataTemplate>
        </material:TabItem.ContentTemplate>
    </material:TabItem>
</material:TabView>

Light - Mobile	Dark - Desktop	Light - iOS

TabHeader Placement

Table tabs can be placed at the top, bottom, start or left of the tab view. You can set the TabPlacement property to Top, Bottom, Start or End to change the placement of the tabs. The default value is Top.

<material:TabView TabPlacement="Bottom">
   <!-- ... -->
</material:TabView>

Light - Android	Dark - Desktop	Light - iOS

Custom Tab Header

You can customize the tab header by setting the TabHeaderItemTemplate property. The TabHeaderItemTemplate property is a DataTemplate that is used to render the tab header. The TabHeaderItemTemplate property is useful when you want to customize the tab header. In the datatemplate Command must be used in binding. That Command must be triggered when use tapped in the custom tab header.

Following parameters can be used in DataTemplate for binding:

• Command: Command that is triggered when user tapped in the tab header.Must be used for functionality of tab view.
• Title: Title of tab.
• Data: It's used to bind custom data to tab header. You can pass this while defining TabItem.

<material:TabView>
    <material:TabView.TabHeaderItemTemplate>
        <DataTemplate>
            <material:CheckBox 
                Text="{Binding Title}" 
                IsChecked="{Binding IsSelected}"
                CheckChangedCommand="{Binding Command}"/>
        </DataTemplate>
    </material:TabView.TabHeaderItemTemplate>
    <!-- ... -->
</material:TabView>

Light - Mobile	Dark - Desktop

Also, tabs can be customized using Triggers according to the state of tab. DataTrigger can be used for styling tab item according to the state of tab. IsSelected property of TabItem can be used in DataTrigger.

<material:TabView>
    <material:TabView.TabHeaderItemTemplate>
        <DataTemplate>
            <Button 
                Text="{Binding Title}"
                Command="{Binding Command}">
                <Button.Triggers>
                    <DataTrigger TargetType="Button" Binding="{Binding IsSelected}" Value="True">
                        <Setter Property="BackgroundColor" Value="{StaticResource SurfaceTint1}" />
                        <Setter Property="TextColor" Value="{StaticResource SurfaceTint3}" />
                        <Setter Property="ImageSource" Value="{FontImageSource FontFamily=MaterialRegular, Glyph={x:Static m:MaterialRegular.Home}, Color={StaticResource SurfaceTint1}}" />
                    </DataTrigger>
                    <DataTrigger TargetType="Button" Binding="{Binding IsSelected}" Value="False">
                        <Setter Property="BackgroundColor" Value="Transparent" />
                        <Setter Property="TextColor" Value="{AppThemeBinding Light={StaticResource OnSurface}, Dark={StaticResource OnSurfaceDark}}" />
                        <Setter Property="ImageSource" Value="{FontImageSource FontFamily=MaterialOutlined, Glyph={x:Static m:MaterialOutlined.Home}, Color={StaticResource SurfaceTint3}}" />
                    </DataTrigger>
                </Button.Triggers>
            </Button>
        </DataTemplate>
    </material:TabView.TabHeaderItemTemplate>
    <material:TabItem Title="Custom Tab One">
        <material:TabItem.Content>
            <Label Text="Tab Content 1" Margin="60" />
        </material:TabItem.Content>
    </material:TabItem>

    <material:TabItem Title="Custom Tab Two">
        <material:TabItem.Content>
            <Label Text="Tab Content 2" Margin="60" />
        </material:TabItem.Content>
    </material:TabItem>

    <material:TabItem Title="Custom Tab Three">
        <material:TabItem.Content>
            <Label Text="Tab Content 3" Margin="60" />
        </material:TabItem.Content>
    </material:TabItem>
</material:TabView>

Light - Mobile	Dark - Desktop

Tabs can be styles separately using HeaderTemplate property of TabItem. Use TabItem.HeaderTemplate property while defining TabItem in TabView.

When both of TabView.TabHeaderItemTemplate and TabItem.HeaderTemplate are defined, TabItem.HeaderTemplate will be used for that particular tab.

Even you can define DataTemplate tab by tab separetely.

<material:TabView>
    <material:TabItem Title="Custom Tab One">
        <material:TabItem.HeaderTemplate>
            <DataTemplate>
                <Button Text="{Binding Title}" Command="{Binding Command}">
                    <Button.Triggers>
                        <DataTrigger TargetType="Button" Binding="{Binding IsSelected}" Value="True">
                            <Setter Property="TextColor" Value="{StaticResource Primary}"/>
                            <Setter Property="Scale" Value="1.2"/>
                        </DataTrigger>
                        <DataTrigger TargetType="Button" Binding="{Binding IsSelected}" Value="False">
                            <Setter Property="TextColor" Value="Gray"/>
                            <Setter Property="Scale" Value="1"/>
                        </DataTrigger>
                    </Button.Triggers>
                </Button>
            </DataTemplate>
        </material:TabItem.HeaderTemplate>
        <material:TabItem.Content>
            <Label Text="Tab Content 1" Margin="60" />
        </material:TabItem.Content>
    </material:TabItem>

    <material:TabItem Title="Custom Tab Two">
        <material:TabItem.Content>
            <Label Text="Tab Content 2" Margin="60" />
        </material:TabItem.Content>
    </material:TabItem>

    <material:TabItem Title="Custom Tab Three">
        <material:TabItem.Content>
            <Label Text="Tab Content 3" Margin="60" />
        </material:TabItem.Content>
    </material:TabItem>
</material:TabView>

Light - Mobile	Dark - Desktop

Dynamic Tabs

TabView supports dynamic tabs. You can add/remove tabs dynamically from a source. ItemsSource and Itemtemplate properties can be used for this purpose.

<material:TabView ItemsSource="{Binding TabItems}">
    <material:TabView.ItemTemplate>
        <DataTemplate>
            <WebView Source="{Binding Url, Mode=TwoWay}" />
        </DataTemplate>
    </material:TabView.ItemTemplate>
</material:TabView>

And view model should be like this.

public class WebTabViewModel : UraniumBindableObject
{
    public ObservableCollection<WebTabItem> TabItems { get; set; } = new()
    {
        new WebTabItem("https://www.bing.com/"),
        new WebTabItem("https://google.com/"),
        new WebTabItem("https://microsoft.com/"),
        new WebTabItem("https://github.com/"),
    };
}

public class WebTabItem : UraniumBindableObject
{
    private string url;
    private string title;

    public WebTabItem(string url = null)
    {
        this.Url = url;
    }

    public string Url
    {
        get => url; set => SetProperty(ref url, value, doAfter: (_url) =>
        {
            if (Uri.TryCreate(_url, UriKind.RelativeOrAbsolute, out Uri uri))
            {
                Title = uri.Host;
            }
        });
    }

    public string Title { get => title; set => SetProperty(ref title, value); }

    public override string ToString()
    {
        return Title;
    }
}

Caching options

TabView has three caching options. CacheOnCodeBehind, CacheOnLayout and RecreateAlways You can choose the best option for your scenario.

You can define caching option by setting CachingStrategy property of TabView.

<material:TabView CachingStrategy="CacheOnCodeBehind" />

• CacheOnCodeBehind: This is the default caching option. It caches the tab contents when the tab is created. The view is removed from the visual tree when a tab is deselected. But instance is kept in memory. And same instance is used when tab is selected again. Reloading the tab content from code-behind to visual tree can take some time when content is huge. It's good for small and simple tab contents. This option is memory friendly. and average performance friendly.

• CacheOnLayout: It caches the tab contents when the tab is created and when the tab is layouted. It's useful when you have a lot of tabs and the tab contents are too complex to create. It's performance friendly when you have a lot of tabs. It's good for large & complex tab contents. This option is the most performance friendly option. But it uses much more memory. It keeps all tab contents in memory.

• RecreateAlways: It refers to no caching. It creates the tab contents always when tab is selected. It's not performance friendly if tab contents are too complex to create. Also, tab contents can't keep their state when tab is selected again.

Customizations

You can customize the TabView by using the style properties. You can use the following example to create your own style:

<Style TargetType="Layout" Class="TabView.Header" ApplyToDerivedTypes="True">
    <Setter Property="BackgroundColor" Value="Black" />
</Style>
<Style TargetType="ContentView" Class="TabView.Content">
    <Setter Property="BackgroundColor" Value="DimGray" />
</Style>