Technical Note TN2179

Creating an About Panel in Your Cocoa Application

A Cocoa application's "About" menu item is set up by sending the message orderFrontStandardAboutPanel: up the responder chain and eventually to NSApplication. When NSApplication receives the message, it goes about building its about panel with various sources of information gathered from the Info.plist file and from the Resources folder in the application bundle. No additional work is required to use the standard about panel so long as you provide the required pieces of information in your Xcode project. You can, however, create and display the standard about panel yourself programmatically with values determined at runtime using the orderFrontStandardAboutPanelWithOptions: message. Another alternative is to completely override this behavior by creating your own about panel.

Property List Values For The About Panel Version Display Format About Panel Using 'orderFrontStandardAboutPanelWithOptions' About Panel Using a Custom 'NSView' Technical Documentation Document Revision History

Property List Values For The About Panel

Information property list files contain essential configuration information for a bundled executable. Most bundles have at least one file of this type (usually named Info.plist) containing most of the bundle’s configuration information. Some of this information is used for the app's about panel.

If you choose to use orderFrontStandardAboutPanelWithOptions: to render your about panel, you need to be familiar with the various attributes and keys used in defining the options dictionary.

Table 1: The following key strings are keys that can be used in the options dictionary:

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Version Display Format

The algorithm for building the about panel's version string, depending on the availability of marketing version (MV) and build version (BV) is displayed in the about panel like so:

Version MV (BV)

Version MV

Version BV

To reiterate from the table above, MV comes from ApplicationVersion in the dictionary; if not provided, then from CFBundleShortVersionString in Info.plist. BV comes from Version in the dictionary; if not provided, then from CFBundleVersion in Info.plist.

Tiger and later systems add the word "Version". Pre-Tiger systems, the character "v" is used instead.

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About Panel Using 'orderFrontStandardAboutPanelWithOptions'

This example illusrates how to use the standard about panel with a dictionary of options. It is up to you if you want to implement the credits section (i.e. by including file "Credits.rtf" in your project). Since it also provides a specific copyright statement, the string "NSHumanReadableCopyright" needs to be removed from the InfoPlist.strings file, if it exists.

Listing 1: Sample that uses 'orderFrontStandardAboutPanelWithOptions'.

#import "Controller.h"

@implementation Controller

- (IBAction)openAboutPanel:(id)sender
{
    NSDictionary *options;
    NSImage *img;

    img = [NSImage imageNamed: @"Picture 1"];
    options = [NSDictionary dictionaryWithObjectsAndKeys:
          @"1.1", @"Version",
          @"Super App", @"ApplicationName",
          img, @"ApplicationIcon",
          @"Copyright 2005-2006, My Great Company", @"Copyright",
          @"Super App v1.1", @"ApplicationVersion",
          nil];

    [[NSApplication sharedApplication] orderFrontStandardAboutPanelWithOptions:options];
}

@end

Figure 1: Sample about panel from Listing 1.

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About Panel Using a Custom 'NSView'

If you wish to build your own custom about panel, you can directly read your app's bundle information and display them in your own panel, window or NSView, for example. Note that in Listing 2, InterfaceBuilder IBOutlets are not used. Rather, each embedded NSView is referenced by it's tag. Also keep in mind that the InfoPlist.strings entries have priority over Info.plist ones.

Listing 2: Sample that shows how to use your own about panel inside a custom NSView.

@interface AboutView : NSView
{}
@end

@implementation AboutView

-(id)infoValueForKey:(NSString*)key
{
    if ([[[NSBundle mainBundle] localizedInfoDictionary] objectForKey:key])
        return [[[NSBundle mainBundle] localizedInfoDictionary] objectForKey:key];

    return [[[NSBundle mainBundle] infoDictionary] objectForKey:key];
}

- (void)drawRect:(NSRect)rect
{
    [super drawRect: rect];

    // draw the background in white
    [[NSColor whiteColor] set];
    [NSBezierPath fillRect:rect];

    // display out NSBundle information
    NSString* nameStr = [self infoValueForKey:@"CFBundleName"];
    NSTextField* field = [self viewWithTag: 1];
    [field setStringValue: nameStr];

    NSString* versionStr = [self infoValueForKey:@"CFBundleVersion"];
    field = [self viewWithTag: 2];
    [field setStringValue: versionStr];

    NSString* copyrightStr = [self infoValueForKey:@"NSHumanReadableCopyright"];
    field = [self viewWithTag: 3];
    [field setStringValue: copyrightStr];

    // draw the app's icon
    NSImage* iconImage = nil;
    NSImageView* imageView = [self viewWithTag: 0];
    NSString* iconFileStr = [self infoValueForKey:@"CFBundleIconFile"];
    if ([iconFileStr length] > 0)
    {
        // we have a real icon
        iconImage = [NSImage imageNamed: iconFileStr];
    }
    else
    {
        // no particular app icon defined, use the default system icon
        iconImage = [NSImage imageNamed: @"NSApplicationIcon"];
        // or
        //NSString* appIconType = NSFileTypeForHFSTypeCode(kGenericApplicationIcon);
        //iconImage = [[NSWorkspace sharedWorkspace] iconForFileType:appIconType];
    }
    [imageView setImage: iconImage];
}

@end

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Technical Documentation

• For further information on "orderFrontStandardAboutPanelWithOptions:" refer to:

  NSApplication Class Reference

• For detailed information on the 'plist' or property list refer to:

  Technote TN2013

• For additional technical information on information property list files based on XML refer to:

  Runtime Configuration Guidelines

• For the Property List Key Reference refer to:

  Introduction to Runtime Configuration Guidelines

• To view a Cocoa sample that uses a fancy about panel refer to:

  FancyAbout

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Document Revision History

Posted: 2007-01-22