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Navigation Services
What are they


By: Tim Mityok of Public Access Software
Copyright ©1998

This Article is an introduction to what Navigation Services are. This is a little techie, and more towards what programmers would care about than lay-people, but does have some general interest as well.

Normally, programmers must use something called "Standard File Dialog" -- this is the dialog that you get when you Open, Close or Save As, using the file menu. Navigation Services is a new API (Library) which replaces that Library with something far better.

How it works

I must say, as both a Macintosh User and also a Programmer, I have rarely seen anything come down from the mighty Apple that has had nearly the impact that the new Navigation Services API had on me.

Look at this image:

Just from a user's perspective everything about the new way to Open and Save files within applications is absolutely brilliant.

  1. The Navigation browser window is now resizable (finally!) allowing you to stretch and distort to accommodate long file names or to show more/fewer items in the item list. (Note the resize area at the bottom-right corner). This alone would be worth the change to NavServices, but there's more.
     
  2. The browser window can also be moved around the screen and does not suspend the rest of the computer until a selection is made. (Normally the Standard File dialog is completely modal -- but Nav Services dialog allows other things to happen).
     
  3. Along the upper left portion of the browser window is a Location popup menu showing you the current location with a volume. This is similar to the location popup menu of traditional Open windows.
     
  4. The list of files, folders and other objects mirrors the new Grayscale Appearance of Mac OS 8 and includes shading as seen in the Mac OS 8 Finder's own list views.
     
  5. There are two sort "buttons", Name and Date Modified. These can be selected to "sort" items accordingly. The Date Modified field shows one of three different date formats depending on how much horizontal space is available. The wider the window, the more information is shown.
     
  6. The sort order widget, the small "arrow" in the upper right corner of list view windows, is also present as in the Finder of Mac OS 8.1 and beyond. This allows users to change to either ascending or descending order (normal or reverse order).
     
  7. The most welcomed addition has to be the inclusion of "disclosure" triangles which allow you to see inside folders or volumes within the context of the entire hierarchy. (So you can display information in multiple directories at the same time).
     
  8. Along the upper right corner is a set of three icon-buttons:
     
    • The first icon-button, called Shortcuts, contains a list of mounted volumes including local and remote hard disks and any removable media. You can even select an "Eject" function for the removable items from this one menu.
       
    • The second icon-button, called Favorites, contains a list of bookmarks to specific folders, volumes or other media. The contents of the Favorites menu is divided into three sections. The first section contains commands for "Add to Favorites..." and "Remove from Favorites...", all book marked files are in the second section and then book marked folders and volumes in the last section.
       
    • The third icon-button, called Recent, contains a list of recently selected objects. Recent files are listed in one section and all recent folder and/or volumes are listed in a second section. Recent files are only shown in Open browser windows and files/volumes are shown in Save browser windows. (The number of recent items will not exceed the settings in the Apple Menu Options Control Panel.)
       
  9. All options and settings are application-specific so you can position and resize a Navigation window in Microsoft Word to show long file names with 10 items and in Photoshop you can have a narrower window with 15 items listed. Also, the Navigation window position is retained for each individual application as well.
  10. When you are presented with a browser window you are automatically taken the the last place you were right down to the object selected, this is the default location.
     
  11. When you move up one level the location you came from is automatically selected in the list (showing you where you just came from), very cool.
     
  12. An additional option is to show a Preview of various files. So if you have QuickTime installed and the file supports Previews. The Preview area is now located to the right of the file list and can be opened or closed using a single button labeled "Show Preview" or "Hide Preview" respectively. The browser window does not adjust its size, instead the file list area compresses to accommodate the Preview section.
     
  13. There are new ways to work with the files and folders as well including numerous keyboard shortcuts for selecting items, navigating the windows and shortcuts for activating various buttons within the window.

The commands are simply too numerous to list here. There is definitely a lot of thought behind all this new System functionality. The point is that these are long overdue, and well needed improvements to the Mac Interface. (Also see ScreenShot #2, and ScreenShot #3)

Not only is all this stuff cool for user, but it is great for programmers as well.

Programming with Navigation Services

For Programmers Navigation Services provide all of the functionality of Standard File Services and then some.

  1. Since so much functionality is already built into the Open and Save dialogs you merely have to ask to open the appropriate window. No more need to for custom-made Open or Save dialog windows!
       
  2. There is, of course, support for customizing the look of the browser window including showing the preview option and the ability to provide file translation capabilities. Navigation services will even automatically convert a document if it is not of a type supported by your application if so configured. The automatic file translation can be turned on or off independently of the file translation options menu added to a browser window. This allows your application to translate a document itself.
     
  3. Navigation Services provides the ability to choose File Objects which can be files, folders only or volumes only. All browser windows are pre-made, you simply make the appropriate call and respond accordingly.
     
  4. You can add your own controls to any browser window, and if you really need to, you can provide custom features specific to your application.

As it stands Navigation Services should fill the needs of the majority of applications present and future.

Conclusion

Navigation Services simply blows away the neglected Standard File which is used everywhere on the Mac OS and is immensely outdated and severely limiting for users. With the new browser window shortcuts and especially the new Favorites list you can quickly navigate to where you want to be and get back to your work. The most annoying aspect of the tradition Open windows in my opinion, the inability to keep track of where you were, has been eliminated altogether.

Many of the changes to Open and Save windows in Navigation Services will be a welcomed relief to those who must be Opening and Saving files repeatedly while they work. For Programmers, they now have a much easier to implement and more powerful system to provide file manipulation services in their application that is also extensible to match their needs. So Navigation Services is not only an improvement for users, but programmers as well. Less work, more functionality, less support calls, better user experience.

Navigation Services provides a tremendous amount of functionality in a System service that is easy to implement in existing applications as well as new ones. It has been shipping for quite a while, and is OS version independent (it is a library that can be dropped in to work on older version of the System as well as future versions).

So while it is unfortunate that Navigation Services are too "geeky" (or technical) for Apple to market effectively, it will definitely be a big "add" as more and more Applications take advantage of it.

Technical Information

Navigation Services exists as a Shared Library on the Mac OS. On 680x0 systems it requires the CFM-68k enabler, however non CFM-68k applications can use Navigation Services. Navigation Services requires System 7.5.5 or newer and Appearance 1.0.1. On 680x0 systems you must use a newer OpenTransportLib.68k file that is included in the Navigation Services SDK.

Created: 6/10/98
Updated: 11/09/02

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