Shell flyout content template

[PureWeen]

Description of Change

Only works on ios/android

This adds the ability to specify your own Content for the Flyout. If you don't want the list of FlyoutItems you can now specify Content or a ContentTemplate and it will render instead of the Flyout Items.

If you specify a Header or a Footer those will also renderer. If the content you specify is scrollable Shell will do its best to honor the Scroll Behavior for the header you've specified

Issues Resolved

• fixes [Spec] Shell Flyout Content Template #6293

API Changes

Added:

• View Shell.FlyoutContent //BP
• DataTemplate Shell.FlyoutContentTemplate //BP
• IEnumerable Shell.FlyoutItems //Readonly list of Flyout Items. The underlying list implements INCC via ReadonlyObservableCollection

Platforms Affected

• Core/XAML (all platforms)

Testing Procedure

• Tests Included

XAML Example

<Shell x:Name=shell>
     <Shell.FlyoutContent>
           <CollectionView 
                    BindingContext="{x:Reference Name=shell}"  
                    IsGrouped=true 
                    ItemSource={Binding FlyoutItems}>
                       <CollectionView.ItemTemplate>
                              <DataTemplate>
                                   <Label Text="{Binding Title}">
                              </DataTemplate>
                       </CollectionView.ItemTemplate>
             </CollectionView>
     </Shell.FlyoutContent>
</Shell>

PR Checklist

• Targets the correct branch
• Tests are passing (or failures are unrelated)

[pictos]

I didn't run the code yet, but I did a quick overview of the code and have these suggestions.

[PureWeen]

https://dev.azure.com/xamarin/public/_releaseProgress?_a=release-pipeline-progress&releaseId=2692

[hartez]

Wondering about that one Update method that's commented out. Other than that, looks fine (though I wouldn't mind seeing some of these longer methods broken up).

[pictos]

Everything works on my tests.