TweetFollow Us on Twitter

Enhancing Your Application with NSStatusItem

Volume Number: 24 (2008)
Issue Number: 07
Column Tag: Application Development

Enhancing Your Application with NSStatusItem

How to utilize the NSStatusItem API to add functionalitys

by Marcus S. Zarra

Introduction

The user interface is arguably the hardest part of any application. This is especially true on OS X because we, as users, demand more of the developers of our applications. If the developer adds too many features and UI elements, then the application feels too busy or complicated. However if too few features are added then application is too primitive or simple.

Fortunately there are some choices. An application that would be considered too simple for the Dock might be perfect on the Dashboard or on the Menu Bar. Likewise, an application that is too busy to be a Dashboard widget might very well be perfectly at home in the Dock. But what if you are in the grey area between the Dock and the Menu Bar? While the design choices between these options ischoices between these options are beyond the scope of this article, I will present how to add a Menu Bar item – also known as a menu extra, menu item or menulet – to to your application and how to control it.

Menu Bar Items: Two Different Beasts

There are two different kinds of objects that can be placed on the menu bar in the upper right corner. First there is the kind that only Apple is allowedallows. The API is private and at the time of this article, third party developers are discouraged from using them.

The second kind that developers are encouraged to use is the NSStatusItem API. The NSStatusItem behaves decidedly different than the internal API that Apple uses. First, NSStatusItem objects cannot be dragged around the menu bar; second they cannot be removed from the menu bar with the mouse; and lastly, they are more "sluggish" than the Apple internal items when another item on the bar is moved or removed.

However, they are still an extremely useful UI element that can be utilized to great effect. The basic concept behind them is that they are a menu with an icon. In that respect, their behavior is very similar to NSMenuItem objects.

Building an NSStatusItem

While it is possible to build an NSStatusItem 100% in code, I prefer to use Interface Builder wherever whenever possible. This makes localizations easier and reduces the amount of code I need to maintain. Therefore, the first step to building an NSStatusItem is to build its menu in Interface Builder.

Building the Menu

To add a new menu to the project, I open the MainMenu.xib file and drag in a new NSMenu object (See Image 1). I normally rename the new menu to "Status Menu" or something similar to keep it clear which menu is which.


Image 1: Drag a new NSMenu into the nib

When an NSMenu is first added it contains three menu items. These items can be added to, removed from and changed as needed. For this example, I have changed the menu so that it has four items: Status, a separator, About and Quit. When I am done the menu looks like Image 2.


Image 2: The finished menu in IB

Now that the menu itself is complete it is time to write some code. For this example, the AppDelegate of my project will be responsible for the NSStatusItem. First, the header:

AppDelegate.h
#import <Cocoa/Cocoa.h>
@interface AppDelegate : NSObject {
   NSStatusItem *myStatusItem;
   IBOutlet NSMenu *myStatusMenu;
   IBOutlet NSMenuItem *myMenuStatusItem;
}
@end

Since both the about menu item and the quit menu item can be handled outside of the AppDelegate in this example, I have not added IBAction methods for them. Once the header has been written, it is time to go back to Interface Builder and link the references as shown in Image 3.

As for the About and Quit menus, they are linked to the Application object as follows:

About -> NSApplication -orderFrontStandardAboutPanel:
Quit -> NSApplication -terminate:

Once all of the linking is complete, I am done withwith the work with Interface Builder is complete;. tTime to move on to the AppDelegate. In this situation I prefer to initialize the NSStatusItem in the applicationDidFinishLaunching: method so that it appears as soon as the application is ready to start receiving events. Depending on an applications particular situation the initialization code can be placed in other locations.

AppDelegate.m
#import "AppDelegate.h"
@implementation AppDelegate
- (void)applicationDidFinishLaunching:(NSNotification*)notification
{
   myStatusItem = [[[NSStatusBar systemStatusBar] statusItemWithLength:NSSquareStatusItemLength] retain];
   
   NSImage *statusImage = [NSImage imageNamed:@"TheZ.tiff"];
   [myStatusItem setImage:statusImage];
   [myStatusItem setHighlightMode:YES];
   
   [myStatusItem setMenu:myStatusMenu];
   
   [myMenuStatusItem setTitle:NSLocalizedString(@"Special Status", @"status menu item text")];
}
@end

The first thing to notice in this code block is that NSStatusItem objects are not initialized directly. Rather, they are requested from an NSStatusBar object. The NSStatusBar object has a class level method that returns the system status bar from which I one can request a NSStatusItem.

Once I have my newthe NSStatusItem request is complete, it is possibleI am able to set its image, highlight mode and menu. The image is the image that is displayed on the Menu Bar and is has a 16x16 resolutionimage. The highlight mode determines whether or not the image is highlighted when clicked. The default is "NO", which is not appropriate when a menu is attached so I have set it to YES in the sample code. The last call to myStatusItem passes it the menu that isI constructed and referenced in Interface Builder. This will be the menu that the NSStatusItem displays when it is clicked.

The last line of the applicationDidFinishLaunching: method is a call to the status menu item that isI referenced from Interface Builder. This call changes the text of that menu item. Note that the sample code doesI have not disabled this menu. Since it does not have a target or action it will be displayed grayed out already so there is no need to disable it.

Controlling The Menu

In various situations it is appropriate to make changes to the NSStatusItem or one of its menu items. In this example, I have intentionally linked the *myStatusMenuItem ivar to one of the NSMenuItem objects on the menu so that it can be changed during the life of the program. To illustrate this change, I added a button to the main window that when clicked would change this menu item:


Image 3: Linking the AppDelegate to the Menu

AppDelegate.h
-(IBAction)changeMenu:(id)sender;
AppDelegate.m
-(IBAction)changeMenu:(id)sender;
{
  [myMenuStatusItem setTitle:NSLocalizedString(@"Changed Status", @"statuc menu item changed text")];
}

With this addition to the application, the status menu item will change to "Changed Status".

It is also possible to change the image that is displayed on the Menu Bar

AppDelegate.h
-(IBAction)purpleZ:(id)sender;
-(IBAction)blackZ:(id)sender;
AppDelegate.m
-(IBAction)purpleZ:(id)sender;
{
   [myStatusItem setImage:[NSImage imageNamed:@"ThePurpleZ.tiff"]];
}
-(IBAction)blackZ:(id)sender;
{
   [myStatusItem setImage:[NSImage imageNamed:@"TheZ.tiff"]];
}

In the example application, I added these actions are added to the Format menu rather than buttons on the main window.

Lastly, if it is desired to have the NSStatusItem as an option rather than a requirement in the application, it is possible to remove the menu item from the bar:

AppDelegate.h
-(IBAction)removeStatusItem:(id)sender;
-(IBAction)addStatusItem:(id)sender;
AppDelegate.m
-(IBAction)removeStatusItem:(id)sender;
{
   [[NSStatusBar systemStatusBar] removeStatusItem:myStatusItem];
   myStatusItem = nil;
}
-(IBAction)addStatusItem:(id)sender;
{
   if (myStatusItem) return;
   myStatusItem = [[[NSStatusBar systemStatusBar] statusItemWithLength:NSVariableStatusItemLength] retain];
   
   [myStatusItem setImage:[NSImage imageNamed:@"TheZ.tiff"]];
   [myStatusItem setHighlightMode:YES];
   [myStatusItem setMenu:myStatusMenu];
   
   [myMenuStatusItem setTitle:NSLocalizedString(@"Special Status", @"status menu item text")];
}
-(BOOL)validateMenuItem:(NSMenuItem*)item
{
   if ([item action] == @selector(removeStatusItem:)) {
      return (myStatusItem != nil);
   }
   if ([item action] == @selector(addStatusItem:)) {
      return (myStatusItem == nil);
   }
   return YES;
}

The code to remove the status item is very simple. Just one call to NSStatusBar -removeStatusItem: and it is gone. Since there is no way to add the existing item back to the bar it is prudent to set the ivar to nil at this time.

To add the NSStatusItem back to the bar, the example I simply copiesd the code from the applicationDidFinishLaunching: method. Ideally this should be abstracted so that the code is not duplicated.

Lastly, I addedthere is a -validateMenuItem: method to make sure that only one status item is ever added and just as importantly, that the application is not trying to remove a non-existent item I do not try to remove a non-existent item.

Now, with the addition of a checkbox in the preferences linked to NSUserDefaults, it is trivial to add a user preference on whether or not to show the status item. OneI could then add logic to the applicationDidFinishLaunching: method to decide whether or not a NSStatusItem needs to be initialized based on the NSUserDefault.

Conclusion

That is all there is to the NSStatusItem API. Hopefully, one day, Apple will allow third party developers to utilize their internal status items so that we can legitimately produce menu bar items that are feature comparable to the system items. Until then, NSStatusItem is a solid API that we can utilize.

As a parting comment, if I wanted my entire application to run as a menu bar item (without a Dock icon ala Twitterific), that only requires one small addition to the Info.plist:

Info.plist
<key>LSUIElement</key>
<string>1</string>

And the application will not bounce in the dock at all. I do not recommend that for this example application as it is not designed to run in that manner but there are plenty of applications that this is perfectly suited for.

NOTE: This change cannot be made to an application on the fly. So if you wanted to make the Dock icon optional also it would require an application restart and probably some trickery with the Finder as the Finder does tend to "cache" the Info.plist file for applications.


Marcus S. Zarra is the owner of Zarra Studios, based out of Colorado Springs, Colorado. He has been developing Cocoa software since 2003, Java software since 1996, and has been in the industry since 1985. Currently Marcus is producing software for OS X. In addition to writing software, he assists other developers by blogging about development and supplying code samples.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Lyn 1.7.2 - Lightweight image browser an...
Lyn is a fast, lightweight image browser and viewer designed for photographers, graphic artists, and Web designers. Featuring an extremely versatile and aesthetically pleasing interface, it delivers... Read more
Lyn 1.7.2 - Lightweight image browser an...
Lyn is a fast, lightweight image browser and viewer designed for photographers, graphic artists, and Web designers. Featuring an extremely versatile and aesthetically pleasing interface, it delivers... Read more
Tunnelblick 3.6.7beta02 - GUI for OpenVP...
Tunnelblick is a free, open source graphic user interface for OpenVPN on OS X. It provides easy control of OpenVPN client and/or server connections. It comes as a ready-to-use application with all... Read more
jAlbum Pro 13.4 - Organize your digital...
jAlbum Pro has all the features you love in jAlbum, but comes with a commercial license. You can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly... Read more
calibre 2.65.1 - Complete e-book library...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital librarian... Read more
jAlbum 13.4 - Create custom photo galler...
With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly, with pro results - Simply drag and drop photos into groups, choose a design... Read more
Backblaze 4.2.0.966 - Online backup serv...
Backblaze is an online backup service designed from the ground-up for the Mac. With unlimited storage available for $5 per month, as well as a free 15-day trial, peace of mind is within reach with... Read more
Backblaze 4.2.0.966 - Online backup serv...
Backblaze is an online backup service designed from the ground-up for the Mac. With unlimited storage available for $5 per month, as well as a free 15-day trial, peace of mind is within reach with... Read more
Tunnelblick 3.6.7beta02 - GUI for OpenVP...
Tunnelblick is a free, open source graphic user interface for OpenVPN on OS X. It provides easy control of OpenVPN client and/or server connections. It comes as a ready-to-use application with all... Read more
calibre 2.65.1 - Complete e-book library...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital librarian... Read more

Siralim 2 (RPG / Roguelike) (Games)
Siralim 2 (RPG / Roguelike) 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Siralim 2 is an old-school monster catching RPG. Summon and customize hundreds of creatures to fight for you as... | Read more »
Clean Text (Productivity)
Clean Text 1.0 Device: iOS Universal Category: Productivity Price: $3.99, Version: 1.0 (iTunes) Description: | Read more »
Gemini - A Journey of Two Stars (Games)
Gemini - A Journey of Two Stars 1.0.1 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.1 (iTunes) Description: *** SPECIAL LAUNCH SALE: $2.99 (25% off) *** "A mesmerizing and unexpectedly emotional journey." -- Los... | Read more »
How to get four NFL superstars for your...
Even though you're probably well on your way to building a top notch squad for the new season in Madden NFL Mobile, let's say you could beef it up by adding Rob Gronkowski, Antonio Brown, Von Miller, and Todd Gurley to your roster. That's... | Read more »
Cartoon Network Superstar Soccer: Goal!!...
Cartoon Network Superstar Soccer: Goal!!! – Multiplayer Sports Game Starring Your Favorite Characters 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Become a soccer superstar with your... | Read more »
NFL Huddle: What's new in Topps NFL...
Can you smell that? It's the scent of pigskin in the air, which either means that cliches be damned, pigs are flying in your neck of the woods, or the new NFL season is right around the corner. [Read more] | Read more »
FarmVille: Tropic Escape tips, tricks, a...
Maybe farming is passé in mobile games now. Ah, but farming -- and doing a lot of a other things too -- in an island paradise might be a little different. At least you can work on your tan and sip some pina coladas while tending to your crops. [... | Read more »
Become the King of Avalon in FunPlus’ la...
King Arthur is dead. Considering the legend dates back to the 5th century, it would be surprising if he wasn’t. But in the context of real-time MMO game King of Avalon: Dragon Warfare, Arthur’s death plunges the kingdom into chaos. Evil sorceress... | Read more »
Nightgate (Games)
Nightgate 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: *** Launch Sale: 25% OFF for a limited time! *** In the year 2398, after a great war, a network of intelligent computers known as... | Read more »
3 best fantasy football apps to get you...
Last season didn't go the way you wanted it to in fantasy football. You were super happy following your drafts or auctions, convinced you had outsmarted everyone. You were all set to hustle on the waiver wire, work out some sweet trades, and make... | Read more »

Price Scanner via MacPrices.net

MacBook Airs on sale for up to $101 off MSRP
Amazon has 11″ and 13″ MacBook Airs on sale for up to $101 off MSRP for a limited time. Shipping is free: - 11″ 1.6GHz/128GB MacBook Air (model MJVM2LL/A): $798 $101 off MSRP - 11″ 1.6GHz/256GB... Read more
Apple certified refurbished iPad mini 4s avai...
Apple has certified refurbished iPad mini 4s now available for up to $120 off the cost of new models. An Apple one-year warranty is included with each iPad, and shipping is free. The following models... Read more
Apple price trackers, updated continuously
Scan our Apple Price Trackers for the latest information on sales, bundles, and availability on systems from Apple’s authorized internet/catalog resellers. We update the trackers continuously: - 15″... Read more
Global Tablet Shipments Projected to Increase...
Digitimes’ Jim Hsiao reports that global tablet shipments will increase by 16.3 percent sequentially to reach nearly 47 million units in 2016′s third quarter, but that volume will still be down over... Read more
Apple’s 2016 Back to School promotion: Free B...
Purchase a new Mac or iPad using Apple’s Education Store and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free, and... Read more
Apple refurbished iPad Air 2s available start...
Apple has Certified Refurbished iPad Air 2 available starting at $339. Apple’s one-year warranty is included with each model, and shipping is free: - 128GB Wi-Fi iPad Air 2: $499 - 64GB Wi-Fi iPad... Read more
13-inch 2.5GHz MacBook Pro available for $961...
Overstock has the 13″ 2.5GHz MacBook Pro available for $961.63 including free shipping. Their price is $138 off MSRP. Read more
Clearance 12-inch Retina MacBooks, Apple refu...
Apple has Certified Refurbished 2015 12″ Retina MacBooks available starting at $929. Apple will include a standard one-year warranty with each MacBook, and shipping is free. The following... Read more
BookBook Releases SurfacePad, BookBook &...
BookBook has released three new covers just for iPad Pro: SurfacePad, BookBook and BookBook Rutledge Edition. BookBook for iPad Pro is a gorgeous leather case reminiscent of a vintage sketchbook.... Read more
Clean Text 1.0 for iOS Reduces Text Cleanup a...
Apimac today announced availability of Clean Text for iOS, a tool for webmasters, graphic designers, developers and magazine editors to reduce text cleanup and editing time, and also for any iPhone... Read more

Jobs Board

*Apple* Retail - Multiple Positions Victor,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* /Mac Support Engineer - GFI Digital,...
FI Digital, Inc. is currently seeking candidates for a full time Apple Support Engineer to add to our Maryland Heights, Missouri IT team. Candidates must be dynamic Read more
SW Engineer *Apple* TV - Apple Inc. (United...
The Apple TV team is looking for excellent software engineers with experience in hardware, media management, media playback, content delivery and a passion for Read more
Senior *Apple* Administrator - Pratt Instit...
POSITION SUMMARY: Directs the coordination and standardization of campus-wide Apple systems, including planning, analysis and implementation of Apple -related Read more
*Apple* Solutions Consultant - Apple (United...
# Apple Solutions Consultant Job Number: 51218534 Pleasant Hill, California, United States Posted: Aug. 18, 2016 Weekly Hours: 40.00 **Job Summary** As an Apple Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.