KKTV iOS 工程師 Mario 分享 影片位置 https://youtu.be/4U9QbQFo7gU 相關 Sessions - [Data Delivery with Drag and Drop] (https://developer.apple.com/videos/wwdc2017/videos/play/wwdc2017/227/) - [Drag and Drop with Collection and Table View] (https://developer.apple.com/videos/wwdc2017/videos/play/wwdc2017/223/) - [Introducing Drag and Drop] (https://developer.apple.com/videos/wwdc2017/videos/play/wwdc2017/203/) - [Mastering Drag and Drop] (https://developer.apple.com/videos/wwdc2017/videos/play/wwdc2017/213/)

1. Drag and Drop in iOS 11
Mario Tung
KKTV

2. Summary
- Goals for drag and drop
- Different phases of a drag session
- Essential Functions
- Drag delegates
- Drop delegates
- Next step

3. What is drag and drop?
A way to move data around

4. Goals for Drag and Drop
Responsive
- On demand / Async data transfer
Secure
- Source app can choose what data to transfer / who to transfer to
- Data is only visible to destination
Great multi touch experience
- Deep integration with iOS apps
- Multiple types of touch/gestures can be used

5. Demo

6. Phases of a drag session
Data transfer time depends on file size

7. Drag begins: get data items
- Use UIDragItems for transferring data
- NSItemProvider only allows objects (not string structs)

8. Get drop proposal during session update
- Called when touch point has moved in view / additional items are added
- Return what to do when user drops item now
- 4 types of UIDropOperations (Cancel / Copy / Move / Forbidden)
- Move operation is only allowed within the same app

9. Perform the drop
- Perform data transfer of objects

10. Customizing Drag and Drop
- Use the drag interaction delegate to find out when views are lifted / being
dragged around
- Use drop interaction delegate to find out when an item has entered view /
dropped into view

11. Drag interaction delegate - Lift
- View to be shown when dragging

12. Drag interaction delegate - Session begins and moves

13. Drag interaction delegate - Adding more items
- Add additional items to drag session
- Update preview view accordingly

14. Drag interaction delegate - End session
- Session is going to end with one of the four types of UIDropOperation

15. Drag interaction delegate - End session (Cancel)

16. Drag interaction delegate - End session (Copy/Move)

17. Drop interaction delegates

18. Drop interaction delegate - Session enters view
- Can be used to filter out types of data that are accepted

19. Drop interaction delegate - Session enters/exits view
- Enter/update/exit can happen multiple times - delegates will keep getting
called

20. Drop interaction delegate - Drop animations
- Execute any further UI changes to the UITargetedDragPreview from
previewForLifting

21. Next step - exploring more