title: iOS App-to-App Trasnmission of Data using new Document Support API
body: <p>Problem:<br>
  <hr>
  Building Enterprise Applications of a Suite Nature, and need to be able to pass data from one application to another.  Example:  App1 is a barcode reader that produces and inventory list.  App2 needs a "fresh" copy of the same inventory list information that App1 just produced in order to accomplish its goal of producing purchase orders.  The two apps and databases are two large to squeeze together in single app, plus the suite will continue to grow with more and more apps.</p>
  
  <p><br />
  Understanding:
  <hr>
  I fully understand that "Each" application is in it's own sandbox.  However, in reading through the documents regarding the new UIDocumentInteractionController API, it appears that an application can dip outside of the sandbox just a little to "Read-In", "View", or "Open-In" a document that was not apart of the bundle or created within the application.</p>
  
  <p><br />
  Data Flow:<hr>
  I'm trying to keep it simple.   I have been using the DocInteraction sample application downloaded from Apple, and another application...called App1 to try and work with a simple text file.  In App1, I create a simple txt file, and save it to the documents folder.  (But this is still inside the app's sandbox?).  in the DocInteraction modified sample, I have been trying to figure a way to "View", "Open-In", or better yet "Read-In" the created txt file.  If I can pass a simple txt file between the two, I can include a CSV structure to update the databases on each side when ever the applications are opened.</p>
  
  <p>I have tried to utilize the Launch Options Keys with no luck.</p>
  
  <p>In short, I just can't seem to get my head around:</p>
  
  <ol>
  <li>Where App1's data needs to go?</li>
  <li>How to find the data in the other App, say App2?</li>
  <li>How do you "Open" the file that exist inside another application's sandbox?</li>
  </ol>
  
  <p>End Result:
  I have tried to stay away from the </p>
  
  <p>The Document Interaction docs outline: </p>
  
  <ul>
  <li>Previewing a Document or Presenting Options</li>
  <li>Registering Your Support of File Types</li>
  <li><strong>Opening Files From Other Apps</strong></li>
  <li>Displaying and Printing Quick Look Previews</li>
  </ul>
  
  <p>It is the "<strong>Opening Files From Other Apps</strong>" that I am most interested with.  It directs me to utilize the application:didFinishLaunchingWithOptions: method by passing in dictionary values for the keys.  This is where I get lost??  How do I set the keys so that it knows "WHERE" and "WHAT" to look for?  And I'm still not clear the proper director that App1 should be saving information to in order for the keys to point to the correct place?</p>
  
  <p><br />
  <strong><em>Opening email file attachments and opening pdfs in iBooks can't be the only places where you can utilize this API or else Apple wouldn't have went through all the work, they are already allow to talk from App-To-App.</em></strong></p>
  
  <p><hr>
  <strong>Note:</strong>  I'm not trying to get App1 to directly transmit data into App2's files.  I don't think that would be allowed by Apple at all!  I'm trying to get App1 to zip up its data, save it in proper location, so when user decides to use App2, the data can then be available to App2 by "reading-in" the data.</p>
  
  <hr>
  
  <p>If someone has a sample application, tutorial, or even a solid idea how to get this working I would really appreciate the help.  </p>
  
  <p>-Thanks!</p>
  
  <p>P.S.  Somebody with 1,500 or higher reputation please create a "UIDocumentInteraction" tag for stackoverflow!</p>