Open Radar

 
Implementing a fully-featured editor for a given file type is no small task, which is why there are an abundance of very nice and well-made iOS apps that provide this much-desired functionality. However, editor apps are severely limited in their use due to the restrictions placed on them by sandboxing technologies. Additionally, other apps which provide non-editing functionality but still add value to the device provide a poor user experience, as they do not provide a full-featured editor, and are unable to defer editing to a more competent app.

UIDocumentInteractionController allows apps to send documents to and from each other, but this is rudimentary at best, and results in duplicate data, which brings along with it the possibility of conflicts. At the user's request, an app should be able to move a document into a shared location, and then display a list of apps registered as editors/viewers (the list part is already possible). The user could then select an editor to use, and be sent to that app. The editor needn't have any knowledge of the app that the user came from, meaning that no collaboration or agreement is necessary between the developers of those apps. The currently available interaction controller system can then be leveraged to send the user back to the original app when they are done editing, with no need to send the document itself back-and-forth at all. Data remains unique, and the user experience is as smooth as possible.

Here is an example use case:

I am writing a blogging engine. I have a Mac version completed, and it simply defers editing of posts to the user's default Markdown editor. This works quite well, and it means that I don't need to write my own dedicated editor.

I would like to create an iOS version of the app, but that would require writing an iOS Markdown editor. There are a few nicely done Markdown editors available now on the App Store, but they required a massive amount of development effort. Using a system like Dropbox could work around the sandbox, but that requires a network connection. It could be accomplished using pasteboards, but that requires collaboration with the editor's developer. Finally, UIDocumentInteractionController results in duplicate data and a poor experience. A shared document system would solve this case, and many more.