ComponentOne Xamarin.Android Edition 2019 v2

Display PDFs in Xamarin with FlexViewer (beta)

• The cross-platform FlexViewer control is now partially supported for the Xamarin Platform. Use the FlexViewer (beta) to display PDF files in your Xamarin.Forms, Xamarin.Android or Xamarin.iOS mobile apps. The viewer supports page navigation and text search.

CollectionView for Xamarin Virtualization Enhancements

• The CollectionView for Xamarin is enhanced with virtualization features including several new collection views designed for specific scenarios. For example, you can implement paged data virtualization by wrapping a C1VirtualCollectionView with a C1PagedCollectionView. Both of these data-providing and transforming collection views are newly added in 2019 v2 along with several others:
  • C1VirtualCollectionView - provides page-like data virtualization with a GetPageAsync() method that populates the collection view. This collection resolves the problem of synchronizing requests and avoiding duplicates.
  • C1PagedCollectionView - provides a paged collection view that supports the ISupportPaging interface that allows controls like C1DataPager to change the pages. This collection is a transforming collection, like C1SortCollectionView or C1FilterCollectionView.
  • C1SelectManyCollectionView - this is like C1SelectCollectionView, but every item of the original collection is converted to a range of items in the resulting collection.
  • C1CacheCollectionView - this collection keeps a reference to the items when they are accessed. It can be used together with C1SelectCollectionView to avoid calling the selector repeatedly for the same item, and thus improve performance.
  • C1SequenceCollectionView - this collection allows composing a range of collection into one sequentially to be exposed as a single collection.
  • C1EditableCollectionView – with this collection view changes made to the collection are tracked locally and aren’t committed to the source immediately. It’s similar to the .NET DataTable.
• This release introduces the EntityFrameworkVirtualCollectionView to join the EntityFrameworkCursorCollectionView. The benefit of the virtual collection view is that when you scroll a list of items, you can go directly to the last item. With the cursor collection view you need to bring the pages in one at a time (and the activity indicator displays at the bottom).The trade off to using the new virtual collection view is that it needs to calculate the total count of items in the table, which can be an expensive database operation.

Other Xamarin Enhancements

• Xamarin.Forms upgraded to 4.0.0.425677
• CollectionView for Xamarin
  • C1PagedCollectionView, ISupportPaging, C1VirtualCollectionView, C1SequenceCollectionView, C1SelectCollectionView, C1SelectManyCollectionView, C1CacheCollectionView, C1EditableCollectionView, C1DelegateList and ISupportAsyncLoading, EntityFrameworkVirtualCollectionView added.
• FlexGrid for Xamarin
  • Rows and Columns.DisableAnimations() allows performing changes in the model without being animated.
  • Performance of load, sort and filter improved for scenarios with a huge number of rows (Model-virtualization).