Specify a particular mime type. Although the K-9 settings file mime

type will not be generally known, specifying something in particular
means that only file browsers that can handle */* will used as options
in the chooser.  In my tests, OI File Manager responds immediately (and
the chooser is bypassed) and the camera, music and ringtone selectors
are not provided as options.

src/com/fsck/k9/activity/Accounts.java

@@ -832,7 +832,7 @@ public class Accounts extends K9ListActivity implements OnItemClickListener, OnC
     private void onImport() {
         Intent i = new Intent(Intent.ACTION_GET_CONTENT);
         i.addCategory(Intent.CATEGORY_OPENABLE);
-        i.setType("*/*");
+        i.setType(MimeUtility.K9_SETTINGS_MIME_TYPE);
         startActivityForResult(Intent.createChooser(i, null), ACTIVITY_REQUEST_PICK_SETTINGS_FILE);
     }