UITableViewDropCoordinator.drop(_:toRowAt:) doesn't work

Originator:an00na
Number:rdar://33160997 Date Originated:July 6 2017, 12:40 PM
Status:Closed Resolved:Behaves as Intended
Product:iOS + SDK Product Version:11.0 beta 2
Classification:UI/Usability Reproducible:Always
 
Area:
UIKit

Summary:
UITableViewDropCoordinator.drop(_:toRowAt:) has no effect. I don't see any drop animation.

Steps to Reproduce:
1. Launch sample app.
2. Drag some text from another app and drop into the list.

Expected Results:
There should be a drop animation.

Observed Results:
No drop animation.

Code: https://mega.nz/#!NawUkLYC!b0GFJ2bvKb-LnklWuO5-RW_9jvJWwX9dbT73N_5IUdc

Comments

Apple Developer Relations July 17 2017, 11:11 PM

The reason the drop animations do not work is because the attached sample app calls drop(_:toRowAt:) after the tableView(_:performDropWith:) method returns, because it is inside a closure that runs asynchronously once the data is loaded.

Drop animations must be specified before returning from tableView(_:performDropWith:), and in cases like this where the data is loading asynchronously you should insert and animate to placeholders which are replaced once the data loads.

Please see the WWDC 2017 Session 223 - Drag and Drop with Collection and Table View: https://developer.apple.com/videos/play/wwdc2017/223/ as well as the associated sample project that contains examples of how to implement this: https://developer.apple.com/sample-code/wwdc/2017/Drag-and-Drop-in-UICollectionView-and-UITableView.zip

By an00na at July 18, 2017, 3:44 p.m. (reply...)

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