TweetFollow Us on Twitter

PowerPlant
Volume Number:11
Issue Number:9
Column Tag:Getting Started

PowerPlant

By Dave Mark, MacTech Magazine Regular Contributing Author

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

This month, we’re going to take a look at PowerPlant, the framework included on every CodeWarrior CD. If you own Symantec C++, take heart: we’ll get to the TCL in a future column. In the meantime, follow along anyway. Who knows, you might find yourself making the switch to PowerPlant someday.

This Month’s Program

I don’t know about you but, after four month’s straight of menus, I’m ready for something else. So instead of talking about PowerPlant and menu handling (we’ll do that in a future column), this month’s program will introduce PowerPlant’s messaging system.

As you design your PowerPlant programs, you’ll work with objects called broadcasters and listeners. A broadcaster sends a message and a listener receives that message. In this month’s program, we’ll create a window containing a button. Each time the button is clicked, it will send a message to any objects registered as listeners to it. Basically, this means that the broadcasting objects’ BroadcastMessage() member function calls the listening object’s ListenToMessage() member function.

This mechanism is simpler than it sounds. As we build our project, just remember that the button is a broadcaster, and that the class CDashboardApp will be the listener.

If you have the CW6 documentation, you might want to read the section named LBroadcaster & LListener in the PowerPlant manual (chapter 8, page 93).

As is usually the case when working with a framework, we’ll take an existing PowerPlant example and modify it to suit our needs.

• Duplicate the folder “CodeWarrior6:Metrowerks PowerPlant:More PowerPlant Examples:Dashboard Starter”.

If you run one of the projects in this folder (either Dashboard68K.µ or DashboardPPC.µ), you’ll see the window shown in Figure 1. To quit the program, select Quit from the File menu. As you can see, Quit is the only item in the File menu. In a future column, we’ll add some menus and items to a PowerPlant program. For now, let’s add a button to the Dashboard window.

Figure 1. The Dashboard Starter window, before our modifications.

Editing Dashboard.PPob

CodeWarrior comes with a ResEdit-like program, named Contructor, that lets you create and edit PowerPlant-specific resources. The resource we’re interested in in this column is the PPob resource. A PPob resource is like a combination of a DLOG and DITL, but for any PowerPlant view including windows and dialogs. We’ll use Constructor to add a button to the Dashboard window.

CodeWarrior 6 ships with two different versions of Constructor. Though both will do the job, Constructor 2.0a16 is far newer than Constructor 1.0.1 and seems pretty stable for an alpha release. The screen shots and instructions in this column were all based on 2.0a16. You’ll find both versions in the CodeWarrior 6 folder, inside the Metrowerks PowerPlant subfolder.

• Launch Constructor 2.0a16 and open the file Dashboard.PPob (it’s in the same folder as the two Dashboard project files).

As you can see by the Constructor window shown in Figure 2, the file Dashboard.PPob already contains a resource. This PPob resource represents the main Dashboard window. It has a resource ID of 200 and represents an object belonging to the class LWindow.

Figure 2. The Constructor window listing the view resources in Dashboard.PPob.

Our next step is to edit this PPob resource.

• Double-click on the LWindow PPob with an id of 200.

When you double-click on PPob 200, a PPob editing window will appear (see Figure 3) showing the object view hierarchy defined by this PPob. Right now, the PPob consists of a single window.

Figure 3. A Constructor window showing PPob 200.

If you click on the window view and select Pane Information... from the Pane menu (or just double-click on the window view), a pane info window will appear (see Figure 4) allowing you to edit the selected view. In this case, the selected view describes a document window with a zoom box, no close box, positioned automatically in the Alert position on the main screen, etc. Feel free to edit this view if you like. To test your changes, quit Constructor, saving your changes, then use CodeWarrior to rerun the project.

Figure 4. The Pane Info window describing the Dashboard window.

Figure 5. The items you can place in a window using Constructor.

With the PPob 200 window in front, you should notice a palette window listing all the items you can place in a PPob view. The palette, shown in Figure 5, works just like ResEdit’s DITL palette. To add an item to a view, drag the item off the palette into the PPob window.

Here’s where we’ll add the button to the window.

• Drag an LStdButton off of the palette into the window view in the PPob 200 window.

• Double-click on the button that appears and edit the info window to match the one shown in Figure 6.

Figure 6. The info window for the LStdButton we added to our window view.

There are three important changes to make in the LStdButton info window. First, change the Pane ID: field to read 1000 (be sure the Text ID checkbox is unchecked before you change the ID). The Pane ID serves to identify the button pane from all the other panes in the PPob resource. By convention, number your panes starting at 1000 and moving upwards from there. For example, if you added three items to the Dashboard window represented by PPob 200, you’d set their Pane IDs to 1000, 1001, and 1002.

The second change to make to the LStdButton info window is to fill in the Button Title: field. Since we want our button to beep, the word Beep will make a fine button title.

The third change is to the Value Message: field. This field contains the message that will get sent when the button is clicked. The message is an integer constant that will be passed as a parameter to any objects registered as listeners to the broadcasting button. Again, by convention, we’ll number our messages starting at 1000.

That’s it. Save your changes and quit Constructor.

Dashboard68K.µ or DashboardPPC.µ

If you haven’t already, open up one of the Dashboard projects (either Dashboard68K.µ or DashboardPPC.µ). Since we want to add a button to our window, we’ll need to add the files that contain the PowerPlant classes that implement push buttons: LControl.cp and LStdControl.cp.

• In the project window, click on the triangle to the left of the group named Pane. When we add the two files, we want to add them to this group.

• Add the files LControl.cp and LStdControl.cp to the project. You’ll find them in the folder “CodeWarrior 6:Metrowerks C/C++:PowerPlant Libraries:Pane Classes”

CDashboardApp.h

• Open the file CDashboardApp.h.

• Add this line after the #include of <LApplication.h>:

#include <LListener.h>

• Change the first line of the CDashboardApp class to look like this:

class CDashboardApp : public LApplication, public LListener {

To convert the CDashboardApp class into a listener, we have to make sure it is derived from the class LListener. Deriving a class from more than one class is perfectly acceptable in C++ and is known as multiple inheritence.

Another step in making the CDashboardApp class a listener is to add a member function named ListenToMessage(). ListenToMessage() will get called when any broadcaster it is listening to broadcasts a message.

• Add this line after the definition of the member function FindCommandStatus():

 virtual void    ListenToMessage(MessageT inMessage, void *ioParam);

• Close CDashboardApp.h and save your changes.

CDashboardApp.cp

Here’s where all the action is. Take some time to look through the file and read all the comments (don’t worry, the file isn’t that long). Notice that main() defines a CDashboardApp object and then calls the member function Run() which was inherited from the LApplication class.

• Add this line after all the other #include files:

#include <LStdControl.h>

Notice that even though we added the files LStdControl.cp and LControl.cp to the project, we don’t include the file <LControl.h>. <LControl.h> is included by <LStdControl.h>.

• In the constructor, find the call of the static function URegister::RegisterClass() and add this line right below it:

 URegistrar::RegisterClass(LStdButton::class_ID,
 LStdButton::CreateStdButtonStream);

This line tells PowerPlant which function to call (LStdButton::CreateStdButtonStream()) when an object of type LStdButton is created based on a PPob resource. Before we came along, this program only needed to register the LWindow class. Since we added an LStdButton object to the PPob resource, we’ll need to register that class as well.

• Also in the constructor, just before the call of mDisplayWindow->Show(), add these lines:

 LStdButton *theButton =
 (LStdButton *)mDisplayWindow->FindPaneByID( 1000 );
 theButton->AddListener( this );

The first line searches the window mDisplayWindow for the pane with the id 1000. Now you know why we entered the number 1000 in the LStdButton’s Pane ID: field.

The second line registers the current object (the CDashboardApp object, known here as this) as a listener of the button we just found.

• At the end of the file, add the member function CDashboardApp::ListenToMessage():

// ----------------------------------------------------------
// • ListenToMessage
// ----------------------------------------------------------
// Respond to message 1000 broadcast by pushbutton

void
CDashboardApp::ListenToMessage(MessageT inMessage, void *ioParam)
{
 if ( inMessage == 1000 )
 SysBeep( 20 );
}

This function will get called whenever the button is clicked. The message 1000 will be passed in as the parameter inMessage.

Figure 7. The Dashboard window. This time it has a button in it.

Running the Program

That’s about it. Save your changes and run the program. The usual Dashboard window will appear, but this time with a button smack-dab in the middle of it. Press the button and, guess what, your Mac will beep at you.

Till Next Month

Obviously, this month’s program gives you only a brief glimpse into the PowerPlant framework. On the other hand, it’s a pretty solid glimpse. Try your hand at adding some other panes to the Dashboard window containment hierarchy. Start by adding a second button with its own pane ID and its own message ID. Next, try to add some other controls.

What part of PowerPlant would you like to learn about next? Should I get into other control types? How about (shudder) menus? Send email. I’ll be waiting to hear from you. See you next month...

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

PDFKey Pro 4.3 - Edit and print password...
PDFKey Pro can unlock PDF documents protected for printing and copying when you've forgotten your password. It can now also protect your PDF files with a password to prevent unauthorized access and/... Read more
Kodi 15.0.beta1 - Powerful media center...
Kodi (was XBMC) is an award-winning free and open-source (GPL) software media player and entertainment hub that can be installed on Linux, OS X, Windows, iOS, and Android, featuring a 10-foot user... Read more
DiskCatalogMaker 6.4.12 - Catalog your d...
DiskCatalogMaker is a simple disk management tool which catalogs disks. Simple, light-weight, and fast. Finder-like intuitive look and feel. Super-fast search algorithm. Can compress catalog data... Read more
Macs Fan Control 1.3.0.0 - Monitor and c...
Macs Fan Control allows you to monitor and control almost any aspect of your computer's fans, with support for controlling fan speed, temperature sensors pane, menu-bar icon, and autostart with... Read more
Lyn 1.5.11 - Lightweight image browser a...
Lyn is a lightweight and fast image browser and viewer designed for photographers, graphic artists and Web designers. Featuring an extremely versatile and aesthetically pleasing interface, it... Read more
NeoOffice 2014.11 - Mac-tailored, OpenOf...
NeoOffice is a complete office suite for OS X. With NeoOffice, users can view, edit, and save OpenOffice documents, PDF files, and most Microsoft Word, Excel, and PowerPoint documents. NeoOffice 3.x... Read more
LaunchBar 6.4 - Powerful file/URL/email...
LaunchBar is an award-winning productivity utility that offers an amazingly intuitive and efficient way to search and access any kind of information stored on your computer or on the Web. It provides... Read more
Remotix 3.1.4 - Access all your computer...
Remotix is a fast and powerful application to easily access multiple Macs (and PCs) from your own Mac. Features Complete Apple Screen Sharing support - including Mac OS X login, clipboard... Read more
DesktopLyrics 2.6.6 - Displays current i...
DesktopLyrics is an application that displays the lyrics of the song currently playing in "iTunes" right on your desktop. The lyrics for the song have to be set in iTunes; DesktopLyrics does nothing... Read more
VOX 2.5.1 - Music player that supports m...
VOX is a beautiful music player that supports many filetypes. The beauty is in its simplicity, yet behind the minimal exterior lies a powerful music player with a ton of features and support for all... Read more

This Week at 148Apps: May 18-22, 2015
May Days at 148Apps How do you know what apps are worth your time and money? Just look to the review team at 148Apps. We sort through the chaos and find the apps you're looking for. The ones we love become Editor’s Choice, standing out above the... | Read more »
Biz Builder Delux (Games)
Biz Builder Delux 1.0.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.0 (iTunes) Description: Ah, there's nothing like the rhythmic bustle of a burgeoning business burg... especially when you're the one building it... | Read more »
Auroch Digital is Bringing Back Games Wo...
| Read more »
Blades of Brim is a New Endless Runner f...
SYBO Games, the minds behind the ever-popular Subway Surfers, have announced their latest project: Blades of Brim. [Read more] | Read more »
Carbo - Handwriting in the Digital Age...
Carbo - Handwriting in the Digital Age 1.0 Device: iOS Universal Category: Productivity Price: $3.99, Version: 1.0 (iTunes) Description: | Read more »
Draggy Dead (Games)
Draggy Dead 1.1 Device: iOS Universal Category: Games Price: $.99, Version: 1.1 (iTunes) Description: Ditch your dead end job and take up a rewarding career in Grave Robbing today!Guide the recently deceased to a fun filled life of... | Read more »
Bad Dinos (Games)
Bad Dinos 1.0.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.0 (iTunes) Description: | Read more »
The Apple Watch isn't Great as a Fi...
| Read more »
Show the World What You See With Stre.am...
Live broadcasting is getting popular on mobile devices, which is why you can now get Stre.am, by Infinite Takes. [Read more] | Read more »
PhotoTime's 2.1 Update Adds Apple W...
The latest PhotoTime update is adding even more functionality to the handy photo organizing app. Yep, including Apple Watch support. [Read more] | Read more »

Price Scanner via MacPrices.net

12-inch MacBook stock status for Monday, May...
The new 12″ Retina MacBooks are still on backorder at The Apple Store with a 3-5 week waiting period. However, a few models are in stock today at Apple resellers. Stock is limited, so act now if you’... Read more
New 27-inch 3.3GHz 5K iMac in stock with free...
Adorama has the new 27″ 3.3GHz 5K iMac in stock today for $1999 including free shipping plus NY & NJ sales tax only. Adorama will include a free copy of Apple’s 3-year AppleCare Protection Plan. Read more
Memorial Day Weekend Sale: New 27-inch 3.3GHz...
Best Buy has the new 27″ 3.3GHz 5K iMac on sale for $1899.99 this weekend. Choose free shipping or free local store pickup (if available). Sale price for online orders only, in-store prices may vary... Read more
OtterBox Maximizes Portability, Productivity...
From the kitchen recipe book to the boarsroom presentation, the OtterBox Agility Tablet System turns tablets into one of the most versatile pieces of handheld technology available. Available now, the... Read more
Launch of New Car App Gallery and Open Develo...
Automatic, a company on a mission to bring the power of the Internet into every car, has announced the launch of the Automatic App Gallery, an app store for nearly every car or truck on the road... Read more
Memorial Day Weekend Sale: 13-inch 1.6GHz Mac...
Best Buy has the new 13″ 1.6GHz/128GB MacBook Air on sale for $849 on their online store this weekend. Choose free shipping or free local store pickup (if available). Sale price for online orders... Read more
Memorial Day Weekend Sale: 27-inch 3.5GHz 5K...
Best Buy has the 27″ 3.5GHz 5K iMac on sale for $2099.99 this weekend. Choose free shipping or free local store pickup (if available). Sale price for online orders only, in-store prices may vary.... Read more
Sale! 16GB iPad mini 3 for $349, save $50
B&H Photo has the 16GB iPad mini 3 WiFi on sale for $349 including free shipping plus NY sales tax only. Their price is $50 off MSRP, and it’s the lowest price available for this model. Read more
Price drop on 2014 15-inch Retina MacBook Pro...
B&H Photo has dropped prices on 2014 15″ Retina MacBook Pros by $200. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $1799.99 save $200 - 15″ 2.5GHz... Read more
With a Mission to Make Mobile Free, Scratch W...
Scratch Wireless, claiming to be the world’s first truly free mobile service, has announced the availability of a new Scratch-enabled Android smartphone, the Coolpad Arise. The smartphone is equipped... Read more

Jobs Board

Payments Counsel, *Apple* Pay (mobile payme...
**Job Summary** Apple is looking for an atto ey to join Apple 's Legal Department to support Apple Pay. **Key Qualifications** 7+ years of relevant experience Read more
Touch Hardware Design and Integration Enginee...
…Summary** Design, develop, and launch next-generation Touch solutions in the new Apple Watch product category. The Touch team develops cutting-edge Touch solutions and Read more
*Apple* Solutions Consultant - Retail Sales...
**Job Summary** As an Apple Solutions Consultant (ASC) you are the link between our customers and our products. Your role is to drive the Apple business in a retail Read more
*Apple* TV Live Streaming Frameworks Test En...
**Job Summary** Work and contribute towards the engineering of Apple 's state-of-the-art products involving video, audio, and graphics in Interactive Media Group (IMG) at 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.