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!

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Minecraft 302 - Popular sandbox building...
Minecraft allows players to build constructions out of textured cubes in a 3D procedurally generated world. Other activities in the game include exploration, gathering resources, crafting, and combat... Read more
FotoMagico 5.2b8 - Powerful slideshow cr...
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
TeamViewer 11.0.65452 - Establish remote...
TeamViewer gives you remote control of any computer or Mac over the Internet within seconds, or can be used for online meetings. Find out why more than 200 million users trust TeamViewer! Free for... Read more
Dropbox 9.4.49 - Cloud backup and synchr...
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
Geekbench 4.0.0 - Measure processor and...
Geekbench provides a comprehensive set of benchmarks engineered to quickly and accurately measure processor and memory performance. Designed to make benchmarks easy to run and easy to understand,... Read more
Nisus Writer Pro 2.1.5 - Multilingual wo...
Nisus Writer Pro is a powerful multilingual word processor, similar to its entry level products, but brings new features such as table of contents, indexing, bookmarks, widow and orphan control,... Read more
Default Folder X 5.0.6 - Enhances Open a...
Default Folder X attaches a toolbar to the right side of the Open and Save dialogs in any OS X-native application. The toolbar gives you fast access to various folders and commands. You just click on... Read more
Alfred 3.1 - Quick launcher for apps and...
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
MYStuff Pro 2.0.25 - Create inventories...
MYStuff Pro is the most flexible way to create detail-rich inventories for your home or small business. Add items to MYStuff by dragging and dropping existing information, uploading new images, or... Read more
OmniOutliner Pro 4.6 - Pro version of th...
OmniOutliner Pro is a flexible program for creating, collecting, and organizing information. Give your creativity a kick start by using an application that's actually designed to help you think. It's... Read more

Lifeline: Crisis Line (Games)
Lifeline: Crisis Line 1.0.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.0 (iTunes) Description: | Read more »
BLUK (Games)
BLUK 1.1 Device: iOS Universal Category: Games Price: $1.99, Version: 1.1 (iTunes) Description: ** ‘Upcoming Game of the Year’ Finalist at NGF Awards 2015 ** ** ‘Big Indie Pitch’ Nominee at Pocket Gamer Connects 2016... | Read more »
Six! Tips, tricks, and hints for beginne...
There's nothing pretentious about Six!, the latest release from Gram Games. As puzzlers go, it's so unassuming that it took me some time to even realize why it was called what it was. Somewhere, my high school geometry teacher is now sobbing... | Read more »
Mobius Final Fantasy: Multiplayer update...
Up until now, Mobius Final Fantasy has been about as single-player an experience as an RPG can be. Not only do you play solo, but you are literally one among a seemingly unending wave of faceless warriors on the road toward the same goal. [Read... | Read more »
Find out the story behind League of Ange...
If you’re looking for a new thrilling MMORPG to play with your friends then you’ll be excited to hear that there is a sequel to one of the most well known titles in the genre – namely League of Angels 2. With a brand new 3D engine offering... | Read more »
Naruto Shippuden: Ultimate Ninja Blazing...
I'm not sure if it's possible to say you are an anime fan but also never have seen one episode of Naruto. If it is, then I resemble that remark, and if not, I offer a hearty apology. [Read more] | Read more »
5 mobile games that let you explore spac...
No Man's Sky hasn't exactly turned out to be everything it was promised. Though its core concept of exploring an unimaginably vast universe of different planets is an intriguing one, the execution has left many PS4 and PC gamers feeling like they... | Read more »
Mummy madness in new action game Tomb He...
Hot on the tail of Bump Hero, ZPlay is giving gamers another reason to get screen bashing with a brand new release. Tomb Heroes is a challenging action game in which you battle enemies in various tombs around the world. You can select from nine... | 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 »

Price Scanner via MacPrices.net

That Upgrade Itch; How Often Do You Upgrade Y...
I have a quandary to resolve as we head into what is typically a major Apple product upgrade season. My mid-2013 MacBook Air will be three years old and my iPad Air 2 will be two come late November.... Read more
Apple refurbished 12-inch iPad Pros available...
Apple has Certified Refurbished 12″ iPad Pros available for up to $160 off the cost of new iPads. An Apple one-year warranty is included with each model, and shipping is free: - 32GB 12″ iPad Pro... Read more
Tim Cook Posts Open Letter To The Apple Commu...
Apple Inc. CEO Tim Cook has posted an open letter commenting on the European Commission’s bizarre demand that Apple pay more than $14 billion in allegedly underpaid back taxes on its Irish... Read more
Streetwise Drivers Club App Now Features Open...
Streetwise Drivers Club, an app that rewards drivers with deals on everything from dining and gift cards to tires and insurance, has announced the launch of a new enhancement connecting app users... Read more
15-inch Retina MacBook Pros on sale for up to...
B&H Photo has 15″ Retina Apple MacBook Pros on sale for up to $200 off MSRP. Shipping is free, and B&H charges NY tax only: - 15″ 2.2GHz Retina MacBook Pro: $1799 $200 off MSRP - 15″ 2.5GHz... Read more
RESCUECOM 2016 Semi-Annual Computer Reliabili...
The beginning of a new school year is upon us again, in which students and parents have some very important choices to make, often including the purchase of a computer or tablet. Whether you are... Read more
VRS Design Damda Glide Series iPhone 7 and 7...
What makes the Damda Glide Series for the iPhone 7 and iPhone 7 Plus special? Case maker VRS Design says its Damda Glide Series is the first mobile case to incorporate a semi-automatic mechanism for... Read more
Apple refurbished iMacs available for up to $...
Apple has Certified Refurbished 2015 21″ & 27″ iMacs available for up to $350 off MSRP. Apple’s one-year warranty is standard, and shipping is free. The following models are available: - 21″ 3.... Read more
Clearance 2015 13-inch MacBook Airs available...
B&H Photo has clearance 2015 13″ MacBook Airs available for $350 off original MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 1.6GHz/4GB/128GB MacBook Air (MJVE2LL/A): $829... Read more
Check Apple prices on any device with the iTr...
MacPrices is proud to offer readers a free iOS app (iPhones, iPads, & iPod touch) and Android app (Google Play and Amazon App Store) called iTracx, which allows you to glance at today’s lowest... Read more

Jobs Board

*Apple* Retail - Multiple Positions Norfolk,...
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* Retail - Multiple Positions- Tampa,...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, 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
*Apple* Solutions Consultant - Apple (United...
Apple Solutions ConsultantJob Number: 51218534Pleasant Hill, California, United StatesPosted: Aug. 18, 2016Weekly Hours: 40.00Job SummaryAs an Apple Solutions Read more
*Apple* Solutions Consultant - Apple (United...
# Apple Solutions Consultant Job Number: 51218354 Fredericksburg, Virginia, 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.