Whats New in iOS 8.0 - A high level look - Part III

iCloud

Below are three main changes in iCloud that impact behavior of existing apps 

Document-Related Data Migration 

The iCloud infrastructure is more robust and reliable when documents are transferred between user device and the server. When user installs iO8.0 devices does a one time migration of the documents and data in that user's account. The migration involves copying documents and data to the new version of apps container directory. This new container is only accessible from iOS 8.0 or OS x 10.0 Devices running on older OS will continue to have access to the original container, but changes made in that container will not appear in the new container and vice versa. 

Cloud Kit

Cloud Kit framework provides a Conduit for moving data between you app and iCloud. Cloud kit gives full control over when the data transfer should occur. One can use cloud kit to manage all kinds of data. 

Apps that use the Cloud kit framework can store the data in a repository that is shared by all users. This public repository is tied to the app itself and is available even on devices without a registered iCloud account. As the app developer, one can manage the data in this repository directly and see the changes made by the users through the iCloud kit dashboard. 

Document Picker

UIDocumentPickerViewController will let the app to show users the documents that are outside the app's sandbox. This is a simple mechanism for sharing documents between apps It also enables complex use cases because multiple apps can edit the document. 

DocumentPicks documents from multiple providers. For e.g. the iCloud document provider grants access to documents stored in another apps iCloud container. 

Unified Storyboard for Universal apps

iOS provides mechanism for developer to create a single interface for both iPhone and iPad screen sizes. Developer can design app for common interface and then adjust the app for different size classes and can tune for better user experience. 

There are two size classes in iOS 8.0. Regular and Compact. A regular screen size indicates that a large amount of space which is available in iPad or a screen size which gives large amount of scroll space such as in iPhone portrait mode.