How do I associate file types with an iPhone application

Question

On the subject of associating your iPhone app with file types.

In this informative question I learned that apps could be associated with custom URL protocols.

That was almost one year ago and since then Apple introduced 'Document Support' which goes a step further and allows apps to associate with file types. There is a lot of talk in the documentation about how to set up your app to launch other appropriate apps when it encounters an unknown file type. This means the association doesn't work out of the box for any app, like the URL protocol registering did.

This leads me to the question: have system apps like Safari or Mail implemented this system for choosing associated applications, or will they do nothing, as before?

User · Answer

BIG WARNING  Make ONE HUNDRED PERCENT sure that your extension is not already tied to some mime type   We used the extension   icz  for our custom files for  basically  ever  and Safari just never would let you open them saying  Safari cannot open this file   no matter what we did or tried with the UT stuff above   Eventually I realized that there are some UT  C functions you can use to explore various things  and while  icz gives the right answer  our app    In app did load at top  just do this     NSString   UTI    NSString   UTTypeCreatePreferredIdentifierForTag kUTTagClassFilenameExtension                                                                       CFStringRef   icz                                                                       NULL   CFURLRef ur  UTTypeCopyDeclaringBundleURL UTI     and put break after that line and see what UTI and ur are -- in our case  it was our identifier as we wanted   and the bundle url  ur  was pointing to our app s folder   But the MIME type that Dropbox gives us back for our link  which you can check by doing e g      curl -D headers THEURLGOESHERE  gt   dev null     Total      Received   Xferd  Average Speed   Time    Time     Time  Current                                  Dload  Upload   Total   Spent    Left  Speed 100 27393  100 27393    0     0  24983      0  0 00 01  0 00 01 -- -- -- 28926   cat headers HTTP 1 1 200 OK accept-ranges  bytes cache-control  max-age 0 content-disposition  attachment  filename  123 icz  Content-Type  text calendar Date  Fri  24 May 2013 17 41 28 GMT etag  872926d pragma  public Server  nginx x-dropbox-request-id  13bd327248d90fde X-RequestId  bf9adc56934eff0bfb68a01d526eba1f x-server-response-time  379 Content-Length  27393 Connection  keep-alive   The Content-Type is what we want  Dropbox claims this is a text calendar entry  Great  But in my case  I ve ALREADY TRIED PUTTING text calendar into my app s mime types  and it still doesn t work  Instead  when I try to get the UTI and bundle url for the text calendar mimetype   NSString   UTI    NSString   UTTypeCreatePreferredIdentifierForTag kUTTagClassMIMEType                                                                      CFStringRef   text calendar                                                                       NULL    CFURLRef ur  UTTypeCopyDeclaringBundleURL UTI     I see  com apple ical ics  as the UTI and      MobileCoreTypes bundle   as the bundle URL  Not our app  but Apple  So I try putting com apple ical ics into the LSItemContentTypes alongside my own  and into UTConformsTo in the export  but no go    So basically  if Apple thinks they want to at some point handle some form of file type  that could be created 10 years after your app is live  mind you   you will have to change extension cause they ll simply not let you handle the file type

User · Answer

To deal with any type of files for my own APP  I use this configuration for CFBundleDocumentTypes        lt key gt CFBundleDocumentTypes lt  key gt       lt array gt           lt dict gt               lt key gt CFBundleTypeName lt  key gt               lt string gt IPA lt  string gt               lt key gt LSItemContentTypes lt  key gt               lt array gt                   lt string gt public item lt  string gt                   lt string gt public content lt  string gt                   lt string gt public data lt  string gt                   lt string gt public database lt  string gt                   lt string gt public composite-content lt  string gt                   lt string gt public contact lt  string gt                   lt string gt public archive lt  string gt                   lt string gt public url-name lt  string gt                   lt string gt public text lt  string gt                   lt string gt public plain-text lt  string gt                   lt string gt public source-code lt  string gt                   lt string gt public executable lt  string gt                   lt string gt public script lt  string gt                   lt string gt public shell-script lt  string gt                   lt string gt public xml lt  string gt                   lt string gt public symlink lt  string gt                   lt string gt org gnu gnu-zip-archve lt  string gt                   lt string gt org gnu gnu-tar-archive lt  string gt                   lt string gt public image lt  string gt                   lt string gt public movie lt  string gt                   lt string gt public audiovisual- content lt  string gt                   lt string gt public audio lt  string gt                   lt string gt public directory lt  string gt                   lt string gt public folder lt  string gt                   lt string gt com apple bundle lt  string gt                   lt string gt com apple package lt  string gt                   lt string gt com apple plugin lt  string gt                   lt string gt com apple application- bundle lt  string gt                   lt string gt com pkware zip-archive lt  string gt                   lt string gt public filename-extension lt  string gt                   lt string gt public mime-type lt  string gt                   lt string gt com apple ostype lt  string gt                   lt string gt com apple nspboard-typ lt  string gt                   lt string gt com adobe pdf lt  string gt                   lt string gt com adobe postscript lt  string gt                   lt string gt com adobe encapsulated- postscript lt  string gt                   lt string gt com adobe photoshop- image lt  string gt                   lt string gt com adobe illustrator ai- image lt  string gt                   lt string gt com compuserve gif lt  string gt                   lt string gt com microsoft word doc lt  string gt                   lt string gt com microsoft excel xls lt  string gt                   lt string gt com microsoft powerpoint  ppt lt  string gt                   lt string gt com microsoft waveform- audio lt  string gt                   lt string gt com microsoft advanced- systems-format lt  string gt                   lt string gt com microsoft advanced- stream-redirector lt  string gt                   lt string gt com microsoft windows- media-wmv lt  string gt                   lt string gt com microsoft windows- media-wmp lt  string gt                   lt string gt com microsoft windows- media-wma lt  string gt                   lt string gt com apple keynote key lt  string gt                   lt string gt com apple keynote kth lt  string gt                   lt string gt com truevision tga-image lt  string gt               lt  array gt               lt key gt CFBundleTypeIconFiles lt  key gt               lt array gt                   lt string gt Icon-76 2x lt  string gt               lt  array gt           lt  dict gt       lt  array gt

User · Answer

In addition to Brad s excellent answer  I have found out that  on iOS 4 2 1 at least  when opening custom files from the Mail app  your app is not fired or notified if the attachment has been opened before  The  open with     popup appears  but just does nothing   This seems to be fixed by  re moving the file from the Inbox directory  A safe approach seems to be to both  re move the file as it is opened  in - BOOL application openURL sourceApplication annotation   as well as going through the Documents Inbox directory  removing all items  e g  in applicationDidBecomeActive   That last catch-all may be needed to get the app in a clean state again  in case a previous import causes a crash or is interrupted

User · Answer

File type handling is new with iPhone OS 3 2  and is different than the already-existing custom URL schemes   You can register your application to handle particular document types  and any application that uses a document controller can hand off processing of these documents to your own application   For example  my application Molecules  for which the source code is available  handles the  pdb and  pdb gz file types  if received via email or in another supported application   To register support  you will need to have something like the following in your Info plist    lt key gt CFBundleDocumentTypes lt  key gt   lt array gt       lt dict gt           lt key gt CFBundleTypeIconFiles lt  key gt           lt array gt               lt string gt Document-molecules-320 png lt  string gt               lt string gt Document-molecules-64 png lt  string gt           lt  array gt           lt key gt CFBundleTypeName lt  key gt           lt string gt Molecules Structure File lt  string gt           lt key gt CFBundleTypeRole lt  key gt           lt string gt Viewer lt  string gt           lt key gt LSHandlerRank lt  key gt           lt string gt Owner lt  string gt           lt key gt LSItemContentTypes lt  key gt           lt array gt               lt string gt com sunsetlakesoftware molecules pdb lt  string gt               lt string gt org gnu gnu-zip-archive lt  string gt           lt  array gt       lt  dict gt   lt  array gt    Two images are provided that will be used as icons for the supported types in Mail and other applications capable of showing documents   The LSItemContentTypes key lets you provide an array of Uniform Type Identifiers  UTIs  that your application can open   For a list of system-defined UTIs  see Apple s Uniform Type Identifiers Reference   Even more detail on UTIs can be found in Apple s Uniform Type Identifiers Overview   Those guides reside in the Mac developer center  because this capability has been ported across from the Mac   One of the UTIs used in the above example was system-defined  but the other was an application-specific UTI   The application-specific UTI will need to be exported so that other applications on the system can be made aware of it   To do this  you would add a section to your Info plist like the following    lt key gt UTExportedTypeDeclarations lt  key gt   lt array gt       lt dict gt           lt key gt UTTypeConformsTo lt  key gt           lt array gt               lt string gt public plain-text lt  string gt               lt string gt public text lt  string gt           lt  array gt           lt key gt UTTypeDescription lt  key gt           lt string gt Molecules Structure File lt  string gt           lt key gt UTTypeIdentifier lt  key gt           lt string gt com sunsetlakesoftware molecules pdb lt  string gt           lt key gt UTTypeTagSpecification lt  key gt           lt dict gt               lt key gt public filename-extension lt  key gt               lt string gt pdb lt  string gt               lt key gt public mime-type lt  key gt               lt string gt chemical x-pdb lt  string gt           lt  dict gt       lt  dict gt   lt  array gt    This particular example exports the com sunsetlakesoftware molecules pdb UTI with the  pdb file extension  corresponding to the MIME type chemical x-pdb   With this in place  your application will be able to handle documents attached to emails or from other applications on the system   In Mail  you can tap-and-hold to bring up a list of applications that can open a particular attachment   When the attachment is opened  your application will be started and you will need to handle the processing of this file in your -application didFinishLaunchingWithOptions  application delegate method   It appears that files loaded in this manner from Mail are copied into your application s Documents directory under a subdirectory corresponding to what email box they arrived in   You can get the URL for this file within the application delegate method using code like the following   NSURL  url    NSURL    launchOptions valueForKey UIApplicationLaunchOptionsURLKey     Note that this is the same approach we used for handling custom URL schemes   You can separate the file URLs from others by using code like the following   if   url isFileURL            Handle file being passed in   else          Handle custom URL scheme

[ios] How do I associate file types with an iPhone application?

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