How to drag-and-drop content between Readdle’s iPad apps

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drag-and-drop readdle iapd
You'll wonder how you ever used your backwards iPad without inter-app drag-and-drop.
Photo: Cult of Mac

If you want to get an idea of how drag-and-drop could work on the iPad, then take a look at Readdle’s latest updates to its iOS productivity apps, which now allow you to drag files between the apps in split-screen view. That’s right, thanks to some very clever hacking, you can seamlessly drag a PDF, photo, or other document, from one app to another. For instance, you can drag scans from Scanner Pro to an email you’re composing in Spark, or you can take an attachment from Spark and drag it into a folder to save in Documents. Let’s take a look at how to do it. Spoiler: it’s pretty easy.

Inter-app drag-and-drop comes to the iPad

Drag-and-drop works with the latest updates of the following Readdle apps: Scanner Pro, Spark, Document, and PDF Expert. To use it, you’ll need an iPad Pro, an iPad Air 2, or an iPad Mini 4. To begin, launch one of these apps, and then add another one using slide-over to put both apps in a split-screen view. Drag-and-drop works in both directions, and it doesn’t matter whether the screen is split 50:50, or with a narrow panel on one side of a large panel.

As far as setup goes, you’re done.

Dragging files is so easy and quick you'll want to use it everywhere on the iPad.
Dragging files is so easy and quick you’ll want to use it everywhere on the iPad.
Photo: Cult of Mac

Depending on the app, you can drag and drop to various places. To begin, tap and hold any document icon. A short moment later the icon will shrink, and follow your finger as you drag it to its destination. Keep going, right across (or under, if you look closely) the center-line between the two apps. The document crosses the line, and can be dropped in the other app. It is at once completely familiar, and completely awesome.

There are some limits

The apps support drag-and-drop differently. In my testing, documents can be dragged from Scanner Pro into the other apps, but you can’t drag a PDF from, say, Spark into Scanner Pro. That makes sense, as Scanner Pro is a place for making documents, not storing them.

Spark, the email client, accepts dragged documents differently depending on whether you have a new draft active on the screen or not. When you do, dragging triggers a drop-zone, a panel with the word Drop Here to appear. If you don’t have an active draft, then a circular drop-zone appears at bottom right, and when you drop your file a new draft is created.

Documents, on the other hand, is far more flexible. Grab an image, document or PDF from an email and drag it over Documents. You can drop it into any available folder, and the app supports spring-loaded folders too. Just hover over a folder (both in the main section and the sidebar), wait a moment, and it will pop open, just like in the Mac’s Finder. You can use this to drill down into any size of folder hierarchy to drop your document. Amazingly, you can even drop it onto the Photo Albums folder and it will be added to your iOS Photo Library.

Drag files to and from your Mac

You can even drag files directly to and from your Mac.
You can even drag files directly to and from your Mac.
Photo: Cult of Mac

This tip is pure gold: because Documents can access folders on your Mac (if they’re on the same network), you can drag files to and from those folders. To make this work, you need to tell Documents to sync a folder from your Mac (or other remote file storage), so that folder will get a permanent place in the Documents sidebar. Here’s how to do that:

  1. Tap +Add in the In the Cloud section of the sidebar.
  2. Tap SFTP Server.
  3. Fill out the title (anything you like), Host (the name of your computer on the network, probably Computer-Name.local, check in the Mac’s Sharing system preference to double check), and the Login and Password (the ones you use to log in to your Mac).
  4. Tap Save
  5. When the list of folders shows up, navigate to the one you want to sync then tap Sync in the top right corner. Tap Sync This Folder to confirm.
  6. The folder appears inside a new Synced folders entry in the Documents sidebar.

(If this doesn’t work, you need to turn on Remote Login in your Mac’s Sharing preferences).

Set it up once and you're done.
Set it up once and you’re done.
Photo: Cult of Mac

Now you can share documents to and from this synced folder. Drag a PDF from a mail, for example, and it will get synced back to your Mac. You can also drag from you iPad to the Mac, and in this case you can do it straight into any Mac folder that happens to be open in Documents, not just synced folders. Dropping it onto the Mac’s icon in the Documents’ sidebar pops open a window with available folders listed. I just used this method to save a PDF from a Spark email direct to My Mac’s desktop. It was amazing. I still feel elated.

How does it all work?

Readdle’s coding geniuses really knocked it out of the park with this one. The feature is so smooth that it feels like native functionality. Behind the scenes, though, things are a lot more complicated. The two apps open up their own HTTP servers, and discover each other using Bonjour. The interfaces of the two apps are synced up so it appears as it you’re dragging the file across, and the actual transfer is done behind the scenes via HTTP. It’s pretty neat stuff.

A peek into the future

This might be a peek into the future of the iPad. Will iOS allow drag-and-drop system wide? Based on Readdle’s work, we now know that it not only works, but is also a completely natural way to work with files on a touch-screen device. Maybe drag-and-drop didn’t make sense back when the iPad was limited to one app on screen at a time, but now, with split view, drag-and-drop seems essential. In fact, if I had to say something bad about Readdle’s version, it’s that drag-and-drop is so useful that I find interacting with files the old way to be a real pain now.