TweetFollow Us on Twitter

Sprocket Menus 1
Volume Number:11
Issue Number:5
Column Tag:Getting Started

Sprocket Menus, Part 1

By Dave Mark, MacTech Magazine Regular Contributing Author

Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.

My February ’93 Getting Started column featured a program called MenuMaster. MenuMaster constructed a menu bar consisting of four menus: The traditional Apple, File, and Edit menus, as well as a special Options menu (Figure 1). Selecting the first item changes it from Change My Name to Change Me Back Again. Selecting the first item again changes it back to Change My Name.

Selecting Disable Me disables the second item and enables the third item. If you then select the newly enabled Enable Previous Item, it gets disabled and Disable Me is reenabled.

If you select Add Extra Menu, a new menu is inserted in the menu bar and Add Extra Menu is disabled. The new menu, titled Extra Menu, features a single item, Delete Me. Selecting Delete Me deletes the extra menu from the menu bar and reenables Add Extra Menu.

Finally, selecting Append Item adds an extra item (Can’t Delete Me...) to the end of the menu. As its names implies, there’s no way to delete this extra item.

Fig. 1. MenuMaster’s Options menu.

A Sprocket Version of MenuMaster

This month we’re going to use Sprocket to implement most of MenuMaster’s functionality. We’ll skip the ability to append an item to the end of a menu for two reasons. First, appending a single item to the end of a menu just isn’t done that often and isn’t particularly useful. More importantly (and probably for the same reason), Sprocket doesn’t give you an easy way to append a new item to a menu.

If you come up with a good reason to add this functionality to Sprocket (or if you have any comments or bugs to report), send e-mail to sprocket@hax.com.

As I mentioned last month, Sprocket based its menu-handling model on that used by OpenDoc. At the heart of this model is a replacement for the MENU resource type. A CMNU resource is just like a MENU resource, with one important addition. Each menu item features a command number. You’ll use this command number to refer to the item, instead of the more traditional method of specifying the menu the item belongs to, along with the item’s position in the menu (e.g., menu 129, item 4).

Figure 2. The CMNU resource, featuring a Cmd-Num field for each menu item.

Check out the ResEdit snapshot in Figure 2. It shows the CMNU resource that represents our new Options menu. The first menu item, Change My Name, is selected. The command number for this item is 1000. When the user selects this item, Sprocket will pass the associated command number (in this case, 1000) as a parameter to the routine HandleMenuCommand() (it’s in the file SprocketStarter.cp). Instead of creating a separate item dispatch routine for each menu (HandleAppleMenu(), HandleFileMenu(), etc.), you’ll create a single switch statement containing cases for all your commands.

Sprocket automatically creates a menu bar at application startup. In C++ terms, Sprocket constructs a TMenuBar object, which is implemented in the files TMenuBar.cp and TMenuBar.h. Here’s the TMenuBar class definition:

class TMenuBar
 {
public:
Resource ('MBAR' and 'CMNU') Utilities
 
 OSErr  GetNewMenuBar(short whichMBAR);
 MenuRefGetMenuFromCMNU(short whichMenu);
Menu command mapping functions

 MenuCommandID   GetCommand(MenuID menu, MenuItemID item);
 void   GetMenuAndItem(MenuCommandID commandNum, 
 MenuID * returnedMenu, MenuItemID * returnedItem);
 OSErr  RegisterCommand(  MenuCommandID commandNum, 
   MenuID menu, MenuItemID item);
 OSErr  UnregisterCommand(MenuCommandID commandNum);
Menu enable/disable routines for menu items

 void   EnableCommand(MenuCommandID commandNum, 
 Boolean enable);
 void   EnableAndCheckCommand(MenuCommandID commandNum, 
 Boolean enable, Boolean check);
 void   GetItemString(MenuCommandID commandNum,
 StringPtr itemString);
 void   SetItemString(MenuCommandID commandNum,
 StringPtr itemString);
helpful utility functions
 void   HideMenuBar();
 void   ShowMenuBar();
 void   RedrawIfNeeded();
 void   Invalidate();
 void   Validate();

private:
"globals"
 static Boolean  fgMenuBarNeedsRedraw;
 static Boolean  fgMenuBarHidden;
mapping tables
 TMenuCommandTable fCommandTable;
 TMenuItemTable  fMenuItemTable;
internal methods
 MenuHandle GetMenuHandleAndItemFromCommand(
 MenuCommandID commandNum, 
 MenuID *menu,MenuItemID *item);
 };

The first member function, GetNewMenuBar() uses the specified MBAR resource to build a new menu bar. Though this version of Sprocket only creates a single menu bar, this might not be the case in the future. For now, a pointer to the menu bar object is stored in the global gMenuBar. Take a minute to open up the file SprocketMain.cp and check out the code around line 363. This is where Sprocket creates the TMenuBar object based on the MBAR resource in SprocketStarter.rsrc.

The member function GetMenuFromCMNU() loads a CMNU resource and walks through it, one item at a time. It builds a traditional menu structure, passing each item’s command number to the RegisterCommand() member function, which adds the command to Sprocket’s menu command table. If you are going to take advantage of Sprocket’s menu command mechanism, you must register your menu item commands. If you base your menus on a CMNU resource, GetMenuFromCMNU() will register your menu items automatically. If the menus in your MBAR resource correspond to a CMNU resource, Sprocket will register the menu items automatically.

If you don’t want to use a CMNU resource, you can still add and delete your menus to and from the global menu bar yourself. For example, since a font or size menu will have a dynamic number of items, the CMNU resource just doesn’t make sense. We’ll look at that process in a future column.

The member function GetCommand() takes a menu and item ID and returns the associated command. GetMenuAndItem() takes a command and returns the associated menu and item ID.

If you want to delete a menu whose commands have been registered, you can use the UnregisterCommand() member function to, one-at-a-time, unregister the commands in that menu. Otherwise, you’ll orphan commands in the command table.

EnableCommand() and EnableAndCheckCommand() let you enable, disable, check, and uncheck a menu command. GetItemString() and SetItemString() allow you to retrieve and set an items name using its command.

HideMenuBar() and ShowMenuBar() let you hide and show the menu bar (what a concept!). Invalidate() marks the menu bar as needing to be redrawn. Validate() sets the menu bar as up to date. RedrawIfNeeded() redraws the menu bar if the invalid flag has been set. Note that RedrawIfNeeded() is called in Sprocket’s main event loop, so there’s no need for you to call it yourself.

This Month’s Resources

Sprocket gets its resources from four different resource files. CreditsBox.rsrc contains the resources used to build the Sprocket about box. StandardMenus.rsrc contains some standard MENU and CMNU resources. If you want to change any of these menus, copy the appropriate resource from StandardMenus.rsrc into SprocketStarter.rsrc and delete the original from StandardMenus.rsrc. Modify the version you copied into SprocketStarter.rsrc.

Sprocket.rsrc contains various resources used by Sprocket and should not be modified. SprocketStarter.rsrc is your resource center. Put all the resources you add to Sprocket there.

You’ll need to modify one resource and add three new ones to SprocketStarter.rsrc. First, open up MBAR 128 and add menu ID 1000 to the list already in place.

If you’re not using Projector (the sourced code control system), you might want to delete the ckid resources you’ll find in each of the resource files. That will get rid of the annoying link error complaining about the multiply-defined resource.

Next, you’ll create your three CMNU resources. The first represents the Options menu we want to add to the end of the menu bar. In general, when you add a new resource to Sprocket, you’ll start numbering your resources from 1000, instead of at 128 the way you normally would. This is just a convention, and might change as Sprocket grows up.

When you create CMNU 1000, be sure to change the resource ID in both places: once in the “Get Info” box and also in the “Edit Menu and MDEF ID” dialog.

Figure 3. CMNU 1000

Enter a command number of 1000 for the item Change My Name, 1001 for Disable Me, 1002 for Enable Previous Item, 1003 for Add Extra Menu, and 1004 for Beeps. Next, disable the item Enable Previous Item. After that, click on the Beeps item, check the has SubMenu checkbox and enter 100 as the submenu ID (Figure 4). Since submenu IDs are limited to a single byte, we won’t be able to give the submenu CMNU resource an ID greater than 1000. So much for sticking to conventions!

Figure 4. The Beeps item, with its submenu ID of 100 entered.

Next, create a new CMNU resource with an ID of 1001 (Once again, be sure to change the ID in both places). The menu will have a title of Extra Menu and a single item, Delete This Menu. Give the item Delete This Menu a command of 1007 (Figure 5).

Figure 5. CMNU 1001

Finally, create a CMNU resource with an ID of 100. Add two items, Beep Once with a command ID of 1005 and Beep Twice with a command ID of 1006 (Figure 6).

Figure 6. CMNU 100.

Save your changes and quit your resource editor.

Modifying the Source Code

Now launch CodeWarrior or Symantec C++ and edit SprocketStarter.h. Start by adding this global reference to the file:

extern Boolean   gItemNameChanged;

gItemNameChanged is a Boolean that indicates whether the item Change My Name has been selected. It tells us whether the item should read Change My Name or Change Me Back Again.

Next, add this enum to the file:

enum
{
 mSubMenu = 100,
 mExtraMenu = 1001,
 
 cChangeName= 1000,
 cDisableMe = 1001,
 cEnablePrevious = 1002,
 cAddExtraMenu   = 1003,
 cBeeps = 1004,
 cBeepOnce= 1005,
 cBeepTwice = 1006,
 cDeleteExtraMenu= 1007
};

The first two constants specify the two CMNU resource IDs. The next 8 specify the menu command IDs. Notice that the menu constants start with a lower case “m” and the commands start with a lower case “c”. Unfortunately, the Apple event registry starts all its class names with a lower-case “c”, so be on the lookout for name collisions.

Next, add these three constants to the file:

const StringPtr kUnchangedName = "\pChange My Name";
const StringPtr kChangedName = "\pChange Me Back Again";
const short kLastMenu = 0;

The first two are just Pascal strings we used for the menu names. We really should have implemented these strings as ‘STR ’ resources to make the code easier to localize. In general, I try never to specify strings in code, but I guess I was just feeling a bit lazy.

The last constant will be used in our call of InsertMenu(), telling InsertMenu() to insert the menu at the end of the menu bar.

Next, edit the file SprocketStarter.cp. Start by adding this global definition at the top of the file:

Boolean gItemNameChanged = false;

Next, add these three lines to the beginning of the routine SetUpApplication():

MenuRef hierMenu;

hierMenu = gMenuBar->GetMenuFromCMNU( mSubMenu );
InsertMenu( hierMenu, -1 ); 

GetMenuFromCMNU() loads CMNU 100, registers all the commands, and returns a MenuHandle to a standard menu based on the CMNU resource. InsertMenu() inserts the resulting menu in the menu bar.

Finally, add the cases to handle our new commands to the switch in HandleMenuCommand() further down in SprocketStarter.cp. Here’s my edited copy of HandleMenuCommand():

HandleMenuCommand
void
HandleMenuCommand(MenuCommandID theCommand)
 {
 MenuRefextraMenu;
 OSErr  err;
 
 switch (theCommand)
 {
 case cAbout:
 AboutBox();
 break;
 
 case cNew:
 CreateNewDocument();
 break;
 
 case cOpen:
 OpenExistingDocument();
 break;
 
 case cPreferences:
 TPreferencesDialogWindow * prefsDialog = 
 new TPreferencesDialogWindow;
 break;
 
#ifqAOCEAware
 case cNewMailableWindow:
 TMailableDocWindow *aWackyThing = new TMailableDocWindow;
 break;
#endif

Here come the new commands. This first one switches the first menu item between Change My Name and Change Me Back Again. Notice that we’re using the global TMenuBar object to change the menus. If Sprocket ever gets modified to use more than one menu bar, we’ll have to modify this code to be sure we use the menu bar that contains the menu we want to work with. Of course, if that happens, you can count on some sample code in this column to show you how to do that.

 case cChangeName:
 if ( gItemNameChanged )
 gMenuBar->SetItemString( cChangeName, kUnchangedName );
 else
 gMenuBar->SetItemString( cChangeName, kChangedName );
 gItemNameChanged = ! gItemNameChanged;
 break;

This command disables Disable Me and enables Enable Previous Item.

 case cDisableMe:
 gMenuBar->EnableCommand( cDisableMe, false );
 gMenuBar->EnableCommand( cEnablePrevious, true );
 break;

This command does just the opposite.

 case cEnablePrevious:
 gMenuBar->EnableCommand( cDisableMe, true );
 gMenuBar->EnableCommand( cEnablePrevious, false );
 break;

This command disables the item that spawned this command in the first place (Add Extra Menu), then builds a new menu from the extra menu CMNU resource. We add the new menu to the end of the menu bar, then call Invalidate() to force the menu bar to get redrawn.

 case cAddExtraMenu:
 gMenuBar->EnableCommand( cAddExtraMenu, false );
 extraMenu = gMenuBar->GetMenuFromCMNU( mExtraMenu );
 InsertMenu( extraMenu, kLastMenu );

 gMenuBar->Invalidate();
 break;

This command deletes the extra menu we added with the previous command. First, we reenable the Add Extra Menu item. Notice that we didn’t have to retrieve the menu that this item belongs to. All we needed was the command. This definitely makes life a lot simpler.

 case cDeleteExtraMenu:
 gMenuBar->EnableCommand( cAddExtraMenu, true );

Since the TMenuBar class doesn’t support a DeleteCMNU() method, we’ll have to deregister the command by hand. A DeleteCMNU() method would step through all the items in the specified menu, calling UnregisterCommand() for each item. It would then delete the menu for us. Since our extra menu only contains a single item, it’s no big deal to do this by hand. Once we are done, we’ll force a menu bar redraw. Look for a DeleteCMNU() method in a future version of Sprocket.

 err = gMenuBar->UnregisterCommand( cDeleteExtraMenu );
 DeleteMenu( mExtraMenu );
 
 gMenuBar->Invalidate();
 break;

This next command corresponds to the parent menu of our hierarchical submenu. Normally, this command will never get called because the menu manager won’t detect a selection of the parent item of a submenu (Figure 7). There are times when this is useful, however. For example, imagine if you built a menu of applications, where each application item had a submenu listing some frequently used documents that can be opened by that application (NowMenus does this). If you select a document from a submenu, its parent application gets launched and opens the selected document. If you release the mouse with the application selected (without selecting a document from the submenu), you might want to launch the application without specifying a document.

The point here is this: Specify commands for all your menu items, even the hierarchical parent menus. A future version of Sprocket might include a workaround to execute commands associated with these currently orphaned items.

 case cBeeps:
 break;

Figure 7. A menu item with its submenu showing.
If the mouse button was released at this point, the Beeps item
(rather than either of the submenu items) would be selected.

These next two items are horribly technical. They beep either once or twice, depending on the item selected.

 case cBeepOnce:
 SysBeep( 20 );
 break;
 case cBeepTwice:
 SysBeep( 20 ); SysBeep( 20 );
 break;
 default:
 break;
 }
 }

Till Next Month

There are still some concepts that we need to get into regarding Sprocket and menus. For example, when do you make the decision about which menu items you will enable and disable to ensure that things are set up correctly before a user makes a selection from a menu. How should the frontmost window affect which menu items are enabled or disabled? We’ll explore these important issues in next month’s column. See you then!

 
AAPL
$97.10
Apple Inc.
+0.07
MSFT
$44.44
Microsoft Corpora
+0.04
GOOG
$588.15
Google Inc.
-5.20

MacTech Search:
Community Search:

Software Updates via MacUpdate

TinkerTool 5.3 - Expanded preference set...
TinkerTool is an application that gives you access to additional preference settings Apple has built into Mac OS X. This allows to activate hidden features in the operating system and in some of the... Read more
Audio Hijack Pro 2.11.0 - Record and enh...
Audio Hijack Pro drastically changes the way you use audio on your computer, giving you the freedom to listen to audio when you want and how you want. Record and enhance any audio with Audio Hijack... Read more
Intermission 1.1.1 - Pause and rewind li...
Intermission allows you to pause and rewind live audio from any application on your Mac. Intermission will buffer up to 3 hours of audio, allowing users to skip through any assortment of audio... Read more
Airfoil 4.8.7 - Send audio from any app...
Airfoil allows you to send any audio to AirPort Express units, Apple TVs, and even other Macs and PCs, all in sync! It's your audio - everywhere. With Airfoil you can take audio from any... Read more
Microsoft Remote Desktop 8.0.8 - Connect...
With Microsoft Remote Desktop, you can connect to a remote PC and your work resources from almost anywhere. Experience the power of Windows with RemoteFX in a Remote Desktop client designed to help... Read more
xACT 2.30 - Audio compression toolkit. (...
xACT stands for X Aaudio Compression Toolkit, an application that encodes and decodes FLAC, SHN, Monkey’s Audio, TTA, Wavpack, and Apple Lossless files. It also can encode these formats to MP3, AAC... Read more
Firefox 31.0 - Fast, safe Web browser. (...
Firefox for Mac offers a fast, safe Web browsing experience. Browse quickly, securely, and effortlessly. With its industry-leading features, Firefox is the choice of Web development professionals... Read more
Little Snitch 3.3.3 - Alerts you to outg...
Little Snitch gives you control over your private outgoing data. Track background activityAs soon as your computer connects to the Internet, applications often have permission to send any... Read more
Thunderbird 31.0 - Email client from Moz...
As of July 2012, Thunderbird has transitioned to a new governance model, with new features being developed by the broader free software and open source community, and security fixes and improvements... Read more
Together 3.2 - Store and organize all of...
Together helps you organize your Mac, giving you the ability to store, edit and preview your files in a single clean, uncluttered interface. Smart storage. With simple drag-and-drop functionality,... Read more

Latest Forum Discussions

See All

Square Register Updates Adds Offline Pay...
Square Register Updates Adds Offline Payments Posted by Ellis Spice on July 25th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Looking For Group – Hearthstone’s Curse...
For the first time since its release (which has thankfully been a much shorter window for iPad players than their PC counterparts), Blizzard’s wildly successful Hearthstone: Heroes of Warcraft CCG is sporting some brand new content: the single... | Read more »
Poptile Review
Poptile Review By Jennifer Allen on July 25th, 2014 Our Rating: :: SIMPLY FUNUniversal App - Designed for iPhone and iPad Simple yet a little bit glorious, Poptile is a satisfying entertaining puzzle game with oodles of the ‘one... | Read more »
Modern Combat 5: Blackout Review
Modern Combat 5: Blackout Review By Brittany Vincent on July 25th, 2014 Our Rating: :: LESS QQ, MORE PEW PEWUniversal App - Designed for iPhone and iPad The fifth entry into the blockbuster Modern Combat series is what mobile... | Read more »
Watch and Share Mobile Gameplay Videos W...
Watch and Share Mobile Gameplay Videos With Kamcord Posted by Jennifer Allen on July 25th, 2014 [ permalink ] iPhone App - Designed for the iPhone, compatible with the iPad | Read more »
THE KING OF FIGHTERS '98 (Games)
THE KING OF FIGHTERS '98 1.0 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0 (iTunes) Description: Series’ masterpiece “KOF ’98” finally joins the battle on iPhone! FEATURES:■ The best game balance in the “KOF”... | Read more »
LEX Goes Free For One Day In Honor of Ne...
LEX Goes Free For One Day In Honor of New Update Posted by Jennifer Allen on July 24th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Thomas Was Alone Goes Universal, Slashes...
Thomas Was Alone Goes Universal, Slashes Price to $3.99 Posted by Ellis Spice on July 24th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Meerkatz Challenge Review
Meerkatz Challenge Review By Jennifer Allen on July 24th, 2014 Our Rating: :: FONDLY PUZZLINGUniversal App - Designed for iPhone and iPad Cute and challenging, Meerkatz Challenge is a fun puzzle game, particularly for fans of... | Read more »
Book Your Appointment with F.E.A.R. this...
Book Your Appointment with F.E.A.R. | Read more »

Price Scanner via MacPrices.net

Mac minis on sale for $100 off MSRP, starting...
Best Buy has Mac minis on sale for $100 off MSRP. Choose free shipping or free instant local store pickup. Prices are for online orders only, in-store prices may vary: 2.5GHz Mac mini: $499.99 2.3GHz... Read more
Global Tablet Market Grows 11% in Q2/14 Notwi...
Worldwide tablet sales grew 11.0 percent year over year in the second quarter of 2014, with shipments reaching 49.3 million units according to preliminary data from the International Data Corporation... Read more
New iPhone 6 Models to Have Staggered Release...
Digitimes’ Cage Chao and Steve Shen report that according to unnamed sources in Apple’s upstream iPhone supply chain, the new 5.5-inch iPhone will be released several months later than the new 4.7-... Read more
New iOS App Helps People Feel Good About thei...
Mobile shoppers looking for big savings at their favorite stores can turn to the Goodshop app, a new iOS app with the latest coupons and deals at more than 5,000 online stores. In addition to being a... Read more
Save on 5th generation refurbished iPod touch...
The Apple Store has Apple Certified Refurbished 5th generation iPod touches available starting at $149. Apple’s one-year warranty is included with each model, and shipping is free. Many, but not all... Read more
What Should Apple’s Next MacBook Priority Be;...
Stabley Times’ Phil Moore says that after expanding its iMac lineup with a new low end model, Apple’s next Mac hardware decision will be how it wants to approach expanding its MacBook lineup as well... Read more
ArtRage For iPhone Painting App Free During C...
ArtRage for iPhone is currently being offered for free (regularly $1.99) during Comic-Con San Diego #SDCC, July 24-27, in celebration of the upcoming ArtRage 4.5 and other 64-bit versions of the... Read more
With The Apple/IBM Alliance, Is The iPad Now...
Almost since the iPad was rolled out in 2010, and especially after Apple made a 128 GB storage configuration available in 2012, there’s been debate over whether the iPad is a serious tool for... Read more
MacBook Airs on sale starting at $799, free s...
B&H Photo has the new 2014 MacBook Airs on sale for up to $100 off MSRP for a limited time. Shipping is free, and B&H charges NY sales tax only. They also include free copies of Parallels... Read more
Apple 27″ Thunderbolt Display (refurbished) a...
The Apple Store has Apple Certified Refurbished 27″ Thunderbolt Displays available for $799 including free shipping. That’s $200 off the cost of new models. Read more

Jobs Board

*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
Sr. Project Manager for *Apple* Campus 2 -...
…the design and construction of one building or building components of the New Apple Campus located in Cupertino, CA. They will provide project management oversight for Read more
WW Sales Program Manager, *Apple* Online St...
**Job Summary** Imagine what you could do here. At Apple , great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
Project Manager / Business Analyst, WW *Appl...
…a senior project manager / business analyst to work within our Worldwide Apple Fulfillment Operations and the Business Process Re-engineering team. This role will work Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.