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
$101.66
Apple Inc.
+0.23
MSFT
$46.70
Microsoft Corpora
-0.31
GOOG
$575.62
Google Inc.
-5.73

MacTech Search:
Community Search:

Software Updates via MacUpdate

Screenshot Path 1.2.1 - Change the defau...
Screenshot Path lets you change the folder where OS X saves screenshots. Screenshots are saved by default to the user’s desktop. This is handy for the occasional screenshot but those looking to take... Read more
Fantastical 1.3.16 - Create calendar eve...
Fantastical is the Mac calendar you'll actually enjoy using. Creating an event with Fantastical is quick, easy, and fun: Open Fantastical with a single click or keystroke Type in your event details... Read more
GIMP 2.8.14 - Powerful, free image editi...
GIMP is a multi-platform photo manipulation tool. GIMP is an acronym for GNU Image Manipulation Program. The GIMP is suitable for a variety of image manipulation tasks, including photo retouching,... Read more
HoudahSpot 3.9.3 - Advanced front-end fo...
HoudahSpot is an advanced file search tool built upon MacOS X Spotlight. Spotlight unleashed Create detailed queries to locate the exact file you need Narrow down searches. Zero in on files Save... Read more
djay 4.2.3 - Transform your Mac into a f...
djay transforms your Mac into a full-fledged DJ system, allowing you to mix your iTunes music library on a hyper-realistic turntable interface. Perform live, record mixes on-the-go, or enable... Read more
iDefrag 2.2.8 - Disk defragmentation and...
iDefrag helps defragment and optimize your disk for improved performance. Features include: Supports HFS and HFS+ (Mac OS Extended). Supports case sensitive and journaled filesystems. Supports... Read more
Bookends 12.2.3 - Reference management a...
Bookends is a full-featured bibliography/reference and information-management system for students and professionals. Access the power of Bookends directly from Mellel, Nisus Writer Pro, or MS Word (... Read more
Copy 1.47.0410 - Cloud storage and file...
Note: You must first sign up to use Copy (get a 5GB sign-up bonus through our 'Download' link above). Copy lets you sync, protect, and share. Everywhere. Want to bring some files home? No problem!... Read more
Stacks 2.6.3 - New way to create pages i...
Stacks is a new way to create pages in RapidWeaver: A plugin designed to combine drag-and-drop simplicity with the power of fluid layout. Features: Fluid Layout: Stacks lets you build pages that... Read more
RestoreMeNot 2.0 - Disable window restor...
RestoreMeNot provides a simple way to disable the window restoration for individual applications so that you can fine-tune this behavior to suit your needs. Please note that RestoreMeNot is designed... Read more

Latest Forum Discussions

See All

This Week at 148Apps: September 8-12, 20...
Expert App Reviewers   So little time and so very many apps. What’s a poor iOS devotee to do? Fortunately, 148Apps is here to give you the rundown on the latest and greatest releases. And we even have a tremendous back catalog of reviews; just check... | Read more »
Rejoice, Kittens! Kitty Powers’ Matchmak...
Rejoice, Kittens! | Read more »
Upcoming Digital Board Game SettleForge...
Upcoming Digital Board Game SettleForge is Headed to iOS Posted by Jessica Fisher on September 12th, 2014 [ permalink ] SettleForge is a single-player board game where players take on the role of the king as they try to | Read more »
Air Supply SOS Set to Bring Retro Sheep...
Air Supply SOS Set to Bring Retro Sheep Rescuing to iOS Soon Posted by Ellis Spice on September 12th, 2014 [ permalink ] Quantum Sheep has announced that the latest entry in the | Read more »
Star Wars: Commander Reveals Who is Winn...
Star Wars: Commander Reveals Who is Winning the Galactic Civil War Posted by Jessica Fisher on September 12th, 2014 [ permalink ] Disney Interactive has released a new infographic detailing the stat | Read more »
The New MOGA REBEL iOS Controller is Set...
The New MOGA REBEL iOS Controller is Set to Be Released on September 17 Posted by Jessica Fisher on September 12th, 2014 [ permalink ] MO | Read more »
Scuba Dupa Review
Scuba Dupa Review By Rob Thomas on September 12th, 2014 Our Rating: :: BUBBLE TROUBLEUniversal App - Designed for iPhone and iPad Scuba Dupa is cute and simple fun, but you’re going to have to part with a bit too much sunken... | Read more »
Get Ready for the iPhone 6 – Amazon Trad...
Get Ready for the iPhone 6 – Amazon Trade-in Program Locks in Used Gadget Prices Until October 10 Posted by Ellis Spice on September 12th, 2014 [ permalink ] | Read more »
Kings of the Realm Review
Kings of the Realm Review By Jennifer Allen on September 12th, 2014 Our Rating: :: STANDARD BASE BUILDINGUniversal App - Designed for iPhone and iPad Kings of the Realm offers some handy tweaks, but it’s still the familiar format... | Read more »
Five Nights at Freddy's (Games)
Five Nights at Freddy's 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: | Read more »

Price Scanner via MacPrices.net

Save $75 on the 16GB iPad mini with Retina Di...
Best Buy has the 16GB iPad mini with Retina Display on sale for $324.99 on their online store for a limited time. Their price is $75 off MSRP, and it’s the lowest price available for this mini.... Read more
21-inch 1.4GHz iMac on sale for $979, $120 of...
B&H Photo has the new 21″ 1.4GHz iMac on sale for $979.99 including free shipping plus NY sales tax only. Their price is $120 off MSRP. B&H will also include free copies of Parallels Desktop... Read more
Apple restocks refurbished 21-inch 1.4GHz iMa...
The Apple Store has restocked Apple Certified Refurbished 21″ 1.4GHz iMacs for $929 including free shipping plus Apple’s standard one-year warranty. Their price is $170 off the cost of new models,... Read more
13-inch 2.6GHz/256GB Retina MacBook Pro on sa...
Adorama has the 13″ 2.6GHz/256GB Retina MacBook Pro on sale for $1379 including free shipping plus NY & NJ sales tax only. Their price is $120 off MSRP, and it’s the lowest price available for... Read more
Macally iPhone 6 Cases
Macally has introduced a Line of Snap-On Shell Cases, Frame Bumper Cases and a Rugged Protective Case for iPhone 6 with 4.7inch Screen, such as the SNAP case in a variety of brilliant metallic... Read more
Belkin Launches New Accessories iPhone 6 and...
Belkin has unveiled a new collection of products for iPhone 6 and iPhone Plus. Belkin’s new iPhone 6 and iPhone 6 Plus accessories include athletic-inspired armbands, classic phone cases and advanced... Read more
Skinit Debuts Customizable Apple iPhone 6 Cas...
Skinit, pioneer creators of protective personalized solutions for consumer electronic devices, has introduced its new collection of customizable Skinit cases and skins for the new Apple iPhone 6.... Read more
Apple refurbished MacBook Pros available for...
The Apple Store has Apple Certified Refurbished 13″ and 15″ MacBook Pros available starting at $929. Apple’s one-year warranty is standard, and shipping is free: - 13″ 2.5GHz MacBook Pros (4GB RAM/... Read more
Save $200 with Apple refurbished 27-inch Thun...
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
Free $25 iTunes gift card with purchase of Ap...
The Apple Store is offering a free $25 iTunes Gift Card with the purchase of a $99 Apple TV for a limited time. Shipping is free. Read more

Jobs Board

*Apple* Retail - Multiple Positions (US) - A...
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
*Apple* Retail - Multiple Positions (US) - A...
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
*Apple* Retail - Multiple Positions (US) - A...
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
*Apple* Retail - Multiple Positions (US) - A...
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
*Apple* Retail - Multiple Positions (US) - A...
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
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.