WWDC 2017

Table of Contents

Data Delivery with Drag & Drop - Thursday

Data Delivery with Drag & Drop - Thursday

Session video and resources: https://developer.apple.com/videos/play/wwdc2017/227/

`NSItemProvider`

Providing data
tableView performDropWith coordinator delegate

Progress & Cancellation

progress.fractionCompleted & progress.isFinished properties for UI
progress.cancel() -> propagates error in completion
One Progress object per load request

Maximize Compatibility

One NSItemProvider = one 'thing' being dragged
Multiple representations
Fidelity order
- Highest fidelity first
Use concrete uniform type identifiers
- Abstract item
  - public.utf8-plain-text
  - public.png
  - Private type identifiers com.yourcompany.vector-drawing

NSItemProviderReading, -Writing Protocols

`NSItemProviderWriting`

writableTypeIdentifiersForItemProvider array with highest fidelity order
loadData(withTypeIdentifier...)

`NSItemProviderReading`

readableTypeIdentifiers array in fidelity order as well
public init(itemProviderData...)

Advanced Topics

Data Marshaling

Providing
- As NSData
- As a file or folder
- As a reference into a file provider
Retrieving
- Copy as NSData
- Copy as file or folder
- Attempt to open file in place

Progress & Cancellation on the Provider Side

Return your own Progress

Per-Representation Visibility

Restrict visibility
- To same application
- To same team
- To everyone
Team Data
- teamData property up to 8 KB of metadata exclusive to your team if needed
Suggested Name
- suggestedName property