The possibility to enrich the functionality of apps and customize the operating system will come with new guidelines and rules developers will have to follow. For one, extensions will always come embedded inside apps users download from the App Store: an extension will be bundled with an app, and developers won’t be able to release standalone extensions on the App Store or submit apps that only contain extensions.
The even bigger reveal from Federighi’s presentation were Actions, app extensions that will allow users to view or manipulate content inside another app. Federighi used two examples to show the “view” and “non-view” nature of extensions: a Bing translate action, which used a feature from the Bing app to translate Japanese text in Safari without showing any additional interface; and a Pinterest web clipper, which presented a custom-designed clipping tool to save an image from a Safari webpage into the Pinterest app without actually launching the app.
More importantly, Actions will nurture the creation of rich workflows that aren’t possible with URL schemes. In a demo shared with developers at WWDC, Apple showed an image annotation tool capable of editing an image from a Safari webpage and insert it back into the webpage when done. It was reminiscent of Markup, a feature of OS X Yosemite that also happens to work as an Action extension. This kind of visual, interactive inter-app communication will result in user-friendly and powerful workflows that will be akin to "mini apps" available right inside a host app without having to switch contexts or be limited by bookmarklets.
Finder Sync will allow apps that sync a local folder with the web to modify the Finder interface with badge icons and custom menus. The latter seems primarily aimed at services like Dropbox, which had to reverse-engineer the Finder to put sync icons and logos on top of folders.
Zorn, who modified the default iOS keyboard with extra rows and buttons in his apps, says he is “thrilled” that Apple is enabling custom keyboards on iOS, but also “a bit disappointed by some of the restrictions”. For example, Apple’s won’t allow keyboards to have any kind of selection controls, so tweaks such as the popular Hooper Selection concept won’t be allowed on the App Store.
Stay up-to-date by subscribing to the Comments RSS Feed for this post.