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

Opera 48.0.2685.50 - High-performance We...
Opera is a fast and secure browser trusted by millions of users. With the intuitive interface, Speed Dial and visual bookmarks for organizing favorite sites, news feature with fresh, relevant content... Read more
Tor Browser Bundle 7.0.7 - Anonymize Web...
The Tor Browser Bundle is an easy-to-use portable package of Tor, Vidalia, Torbutton, and a Firefox fork preconfigured to work together out of the box. It contains a modified copy of Firefox that... Read more
FotoMagico 5.5 - Powerful slideshow crea...
FotoMagico lets you create professional slideshows from your photos and music with just a few, simple mouse clicks. It sports a very clean and intuitive yet powerful user interface. High image... Read more
Adobe Audition CC 2018 11.0.0 - Professi...
Audition CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Audition customer). Adobe Audition CC 2018 empowers you to create and... Read more
Alfred 3.5.1 - Quick launcher for apps a...
Alfred is an award-winning productivity application for OS X. Alfred saves you time when you search for files online or on your Mac. Be more productive with hotkeys, keywords, and file actions at... Read more
AirRadar 4.0 - $9.95
With AirRadar, scanning for wireless networks is now easier and more personalized! It allows you to scan for open networks and tag them as favourites or filter them out. View detailed network... Read more
DEVONthink Pro 2.9.16 - Knowledge base,...
Save 10% with our exclusive coupon code: MACUPDATE10 DEVONthink Pro is your essential assistant for today's world, where almost everything is digital. From shopping receipts to important research... Read more
ForkLift 3.0.8 Beta - Powerful file mana...
ForkLift is a powerful file manager and ferociously fast FTP client clothed in a clean and versatile UI that offers the combination of absolute simplicity and raw power expected from a well-executed... Read more
Data Rescue 5.0.1 - Powerful hard drive...
Data Rescue’s new and improved features let you scan, search, and recover your files faster than ever before. We have modernized the file-preview capabilities, added new files types to the recovery... Read more
Dropbox 37.4.29 - Cloud backup and synch...
Dropbox is an application that creates a special Finder folder that automatically syncs online and between your computers. It allows you to both backup files and keep them up-to-date between systems... Read more

Halcyon 6: Starbase Commander (Games)
Halcyon 6: Starbase Commander 1.4.2.0 Device: iOS Universal Category: Games Price: $6.99, Version: 1.4.2.0 (iTunes) Description: An epic space strategy RPG with base building, deep tactical combat, crew management, alien diplomacy,... | Read more »
Legacy of Discord celebrates its 1 year...
It’s been a thrilling first year for fans of Legacy of Discord, the stunning PvP dungeon-crawling ARPG from YOOZOO Games, and now it’s time to celebrate the game’s first anniversary. The developers are amping up the festivities with some exciting... | Read more »
3 reasons to play Thunder Armada - the n...
The bygone days of the Battleship board game might have past, but naval combat simulators still find an audience on mobile. Thunder Armada is Chinese developer Chyogames latest entry into the genre, drawing inspiration from the explosive exchanges... | Read more »
Experience a full 3D fantasy MMORPG, as...
Those hoping to sink their teeth into a meaty hack and slash RPG that encourages you to fight with others might want to check out EZFun’s new Eternity Guardians. Available to download for iOS and Android, Eternity Guardians is an MMORPG that lets... | Read more »
Warhammer Quest 2 (Games)
Warhammer Quest 2 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Dungeon adventures in the Warhammer World are back! | Read more »
4 of the best Halloween updates for mobi...
Halloween is certainly one of our favorite times for mobile game updates. Many popular titles celebrate this spooky season with fun festivities that can stretch from one week to even the whole month. As we draw closer and closer to Halloween, we'... | Read more »
Fire Rides guide - how to swing to succe...
It's another day, which means another Voodoo game has come to glue our hands to our mobile phones. Yes, it's been an especially prolific month for this particular mobile publisher, but we're certainly not complaining. Fire Rides is yet another... | Read more »
Time Recoil (Games)
Time Recoil 1.0.1 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0.1 (iTunes) Description: Time Recoil is a top-down shooter where you kill to slow time, dominate slow motion gunfights, and trigger devastating special... | Read more »
Campfire Cooking (Games)
Campfire Cooking 1.0 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0 (iTunes) Description: | Read more »
Returner 77 (Games)
Returner 77 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Returner 77 is a cinematic space mystery puzzle game. You are in a giant alien spaceship hovering above Earth, after everything... | Read more »

Price Scanner via MacPrices.net

Apple restocks full line of refurbished 13″ M...
Apple has restocked a full line of Apple Certified Refurbished 2017 13″ MacBook Pros for $200-$300 off MSRP. A standard Apple one-year warranty is included with each MacBook, and shipping is free.... Read more
13″ 3.1GHz/256GB MacBook Pro on sale for $167...
Amazon has the 2017 13″ 3.1GHz/256GB Space Gray MacBook Pro on sale today for $121 off MSRP including free shipping: – 13″ 3.1GHz/256GB Space Gray MacBook Pro (MPXV2LL/A): $1678 $121 off MSRP Keep an... Read more
13″ MacBook Pros on sale for up to $120 off M...
B&H Photo has 2017 13″ MacBook Pros in stock today and on sale for up to $120 off MSRP, each including free shipping plus NY & NJ sales tax only: – 13-inch 2.3GHz/128GB Space Gray MacBook... Read more
15″ MacBook Pros on sale for up to $200 off M...
B&H Photo has 15″ MacBook Pros on sale for up to $200 off MSRP. Shipping is free, and B&H charges sales tax in NY & NJ only: – 15″ 2.8GHz MacBook Pro Space Gray (MPTR2LL/A): $2249, $150... Read more
Roundup of Apple Certified Refurbished iMacs,...
Apple has a full line of Certified Refurbished 2017 21″ and 27″ iMacs available starting at $1019 and ranging up to $350 off original MSRP. Apple’s one-year warranty is standard, and shipping is free... Read more
Sale! 27″ 3.8GHz 5K iMac for $2098, save $201...
Amazon has the 27″ 3.8GHz 5K iMac (MNED2LL/A) on sale today for $2098 including free shipping. Their price is $201 off MSRP, and it’s the lowest price available for this model (Apple’s $1949... Read more
Sale! 10″ Apple WiFi iPad Pros for up to $100...
B&H Photo has 10.5″ WiFi iPad Pros in stock today and on sale for $50-$100 off MSRP. Each iPad includes free shipping, and B&H charges sales tax in NY & NJ only: – 10.5″ 64GB iPad Pro: $... Read more
Apple iMacs on sale for up to $130 off MSRP w...
B&H Photo has 21-inch and 27-inch iMacs in stock and on sale for up to $130 off MSRP including free shipping. B&H charges sales tax in NY & NJ only: – 27″ 3.8GHz iMac (MNED2LL/A): $2179 $... Read more
2017 3.5GHz 6-Core Mac Pro on sale for $2799,...
B&H Photo has the 2017 3.5GHz 6-Core Mac Pro (MD878LL/A) on sale today for $2799 including free shipping plus NY & NJ sales tax only . Their price is $200 off MSRP. Read more
12″ 1.2GHz Space Gray MacBook on sale for $11...
Amazon has the 2017 12″ 1.2GHz Space Gray Retina MacBook on sale for $100 off MSRP. Shipping is free: 12″ 1.2GHz Space Gray MacBook: $1199.99 $100 off MSRP Read more

Jobs Board

*Apple* Retail - Multiple Positions - Farmin...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
Frameworks Engineer, *Apple* Watch - Apple...
Job Summary Join the team that is shaping the future of software development for Apple Watch! As a software engineer on the Apple Watch Frameworks team you will Read more
*Apple* News Product Marketing Mgr., Publish...
Job Summary The Apple News Product Marketing Manager will work closely with a cross-functional group to assist in defining and marketing new features and services. Read more
Fraud Analyst, *Apple* Advertising Platform...
Job Summary Apple Ad Platforms has an opportunity to redefine advertising on mobile devices. Apple reaches hundreds of millions of iPhone, iPod touch, and iPad Read more
*Apple* Information Security - Security Data...
Job Summary This role is responsible for helping to strengthen Apple 's information security posture through the identification and curation of security event data. Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.