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...

 
AAPL
$100.86
Apple Inc.
-0.77
MSFT
$46.76
Microsoft Corpora
+0.52
GOOG
$579.95
Google Inc.
+6.85

MacTech Search:
Community Search:

Software Updates via MacUpdate

Capture One Pro 8.0.0.433 - RAW workflow...
Capture One Pro 8 is a professional RAW converter offering you ultimate image quality with accurate colors and incredible detail from more than 300 high-end cameras -- straight out of the box. It... Read more
Adobe Acrobat Pro 11.0.09 - Powerful PDF...
Adobe Acrobat allows users to communicate and collaborate more effectively and securely. Unify a wide range of content in a single organized PDF Portfolio. Collaborate through electronic document... Read more
Adobe Reader 11.0.09 - View PDF document...
Adobe Reader allows users to view PDF documents. You may not know what a PDF file is, but you've probably come across one at some point. PDF files are used by companies and even the IRS to... Read more
iFFmpeg 4.6.1 - Convert multimedia files...
iFFmpeg is a graphical front-end for FFmpeg, a command-line tool used to convert multimedia files between formats. The command line instructions can be very hard to master/understand, so iFFmpeg does... Read more
NTFS 11.3.62 - Provides full read and wr...
Paragon NTFS breaks down the barriers between Windows and OS X. Paragon NTFS effectively solves the communication problems between the Mac system and NTFS, providing full read and write access to... Read more
OS X Yosemite 10.10 DP8 - Developer Prev...
Note: This is a Developer Preview. You must be a registered Apple Mac Developer to download this update. You can also sign up for the free OS X Beta Program to download and preview public beta... Read more
FotoMagico 4.5 - Powerful slideshow crea...
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
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

Latest Forum Discussions

See All

Zynga Unveils First Look at Looney Tunes...
Zynga Unveils First Look at Looney Tunes Dash! Posted by Ellis Spice on September 16th, 2014 [ permalink ] Be vewy, vewy qwiet. I’m hunting wunners featuwing wabbits, and luckily, it’s duck season wunner season. | Read more »
Guardians on the Go – How to Connect to...
At this point I’m relatively certain most of the country is familiar with Destiny. And for those looking to augment their game a bit, Bungie has changed their Bungie Mobile Companion App to Destiny Companion. | Read more »
Kunin Review
Kunin Review By Jordan Minor on September 16th, 2014 Our Rating: :: SHURIKEN DO ITUniversal App - Designed for iPhone and iPad Kunin is a nervous test of ninja reflexes.   Developer: Dodreams Price: FREE Version Reviewed: 1.0.1... | Read more »
4 KEMCO Titles are Just $0.99 for a Limi...
4 KEMCO Titles are Just $0.99 for a Limited Time Posted by Jessica Fisher on September 16th, 2014 [ permalink ] KEMCO RPGs Destiny Fantasia, Infinite Dunamis, Bonds of the Sk | Read more »
Introducing Flash, the Latest Wearable F...
Introducing Flash, the Latest Wearable Fitness Monitor from Misfit Posted by Jessica Fisher on September 16th, 2014 [ permalink ] The Misfit Flash is the newly-released fitness and sleep monitor from | Read more »
Hyper Trip Review
Hyper Trip Review By Jennifer Allen on September 16th, 2014 Our Rating: :: HYPER TWITCHYUniversal App - Designed for iPhone and iPad Tough and unforgiving, Hyper Trip is a bit like Snake – if Snake was really harsh.   | Read more »
Collectible Card Game Earthcore: Shatter...
Collectible Card Game Earthcore: Shattered Elements is Set to Arrive on iOS in 2015 Posted by Ellis Spice on September 16th, 2014 [ permalink ] Polish developers | Read more »
Boogey Boy Review
Boogey Boy Review By Jennifer Allen on September 16th, 2014 Our Rating: :: PRETTY BUT BASICUniversal App - Designed for iPhone and iPad It looks delightful but lack of Game Center support and more variety really affects the fun... | Read more »
Vizzywig 4K (Photography)
Vizzywig 4K 1.0 Device: iOS iPhone Category: Photography Price: $999.99, Version: 1.0 (iTunes) Description: REQUIRES: iOS 7 on iPhone 5S with 32GB or 64GB. (Do not use iOS 8)The world's FIRST mobile 4K video capture, editing and... | Read more »
The Sleeping Prince Review
The Sleeping Prince Review By Jennifer Allen on September 15th, 2014 Our Rating: :: RESTRICTIVE KINGDOM SAVINGUniversal App - Designed for iPhone and iPad The Sleeping Prince looks and feels great to play, but its lack of peril and... | Read more »

Price Scanner via MacPrices.net

Sprint offers 16GB iPad mini for $199.99 with...
Sprint is offering 1st generation 16GB iPad minis for $199.99 with a 2-year service agreement. Standard MSRP for this iPad is $429. Their price is the lowest available for this model. Read more
2.5GHz Mac mini remains on sale for $549, sav...
B&H Photo has the 2.5GHz Mac mini on sale for $549.99 including free shipping. That’s $50 off MSRP, and B&H will also include a free copy of Parallels Desktop software. NY sales tax only. Read more
Apple refurbished iMacs available for up to $...
The Apple Store has Apple Certified Refurbished iMacs available for up to $300 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free. These are the best prices on... Read more
13″ 2.5GHz MacBook Pro offered for $100 off M...
B&H Photo has the 13″ 2.5GHz MacBook Pro on sale for $999.99 including free shipping plus NY sales tax only. Their price is $100 off MSRP. Read more
Free GIMP Professional Grade Graphics App Ver...
The latest 2.8.14 version of the oddly-named GIMP (acronym for: GNU Image Manipulation Program) open source, high-end image editing and creation alternative to Adobe’s Photoshop and refuge from... Read more
Apple Announces Record Pre-orders for iPhone...
Apple has released metrics showing a record number of first day pre-orders of iPhone 6 and iPhone 6 Plus, with over four million sold in the first 24 hours. Demand for the new iPhones exceeds the... Read more
10% off iPhone 6 and 6 Plus Otterbox cases
Get 10% off on popular Otterbox iPhone 6 and iPhone 6 Plus cases at MacMall through September 19th. Use code OTTERBOX10 to see the discount. Read more
15-inch MacBook Pros on sale for up to $125 o...
Amazon has the new 2014 15″ Retina MacBook Pros on sale for up to $125 off MSRP including free shipping: - 15″ 2.2GHz Retina MacBook Pro: $1899.99 save $100 - 15″ 2.5GHz Retina MacBook Pro: $2374... Read more
27-inch 3.2GHz iMac on sale for $1698, $101 o...
Abt has the 27″ 3.2GHz iMac on sale for $1698 including free shipping. Their price is $101 off MSRP. Read more
More To Making A Larger iPad Than Expanded Sc...
CNET’s Ross Rubin has posted a thoughtful analysis of prospects for a larger display iPad Pro, noting that Microsoft and Samsung currently have the large-display touchscreen tablet category to... 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.