TweetFollow Us on Twitter

More on Xcode

Volume Number: 19 (2003)
Issue Number: 9
Column Tag: Programming

Geeting Started

More on Xcode

by Dave Mark

I must say, I am really enjoying digging into Xcode. I'm impressed with what I've seen so far. The bugs I've encountered have mostly been cosmetic and, I assume, easily fixable. My understanding is that the WWDC release is the only Jaguar release and that all fixes and future releases will be Panther-only.

For the moment, I'll stick with the Jaguar version. As soon as a "for public consumption" version of the Panther Xcode makes its way into my hot little hands, I'll shift permanently into Panther mode.

Editor Window Details

Last month's column started off by opening an existing Project Builder project called Sketch.pbxproj in Xcode and updating the target, creating a new target called Sketch (Upgrade). Go ahead and launch Xcode and open the project. If you are starting from scratch, you'll find Sketch.pbxproj in the directory /Developer/Examples/AppKit/Sketch/. Remember, you can open a project by navigating to the right directory and clicking the Open button. Xcode will find the project file for you.

When the project window appears, click and hold on the Build and Debug icon. After a slight pause, a drop-down menu will appear (see Figure 1). The little triangle to the lower right of an Xcode tool icon is your clue that there's a drop-down menu lurking within. Just remember to hold and wait a hitch for the menu to appear.


Figure 1. The Build and Debug drop-down menu.

Go ahead and select Build and Debug from the drop-down menu. Xcode will build and launch a debug-ready version of Sketch and open the debugger window. As you'd expect, the debugging window allows you to control the debugging process.

Use the Dock to bring Sketch to the front. Click on the rectangles icon in the palette, then click and drag out a rectangle in the main window (see Figure 2). Note that the rectangle that appears is not filled.


Figure 2. Dragging out a rectangle with Sketch.

Now go back to the project window and click on the Project Symbols group (the last group in the Groups & Files column). As you saw last month, this "smart group" lists all the symbols in the project. Type init in the search field to reduce the list of symbols (See Figure 3).


Figure 3. Using the search field to find the init method in SKTGraphic.m.

We're looking for the init method in the file SKTGraphic.m. There are two ways to open this file from the listing in the Project Symbols group. We can click on the Editor icon in the toolbar (the cursor is pointing to this icon in Figure 3) to open an editing pane for that file in the Project Window. Alternatively, we can double-click on the line listing the file we want to open that file in a separate editing window. That's the method we're going to use here.

Figure 4 shows the editor window that appeared when I double-clicked on SKTGraphic.m. At the top of the window is the editor toolbar. Just beneath that is the status bar (in Figure 4 it says Sketch (Upgraded)).


Figure 4. A new editing window listing the file SKTGraphic.m.

Below the status bar is the navigation bar. Towards the left edge of the nav bar is a pair of arrows. These act like the left and right arrows in your browser and are used to move between source files. You'll see how this works in a sec.

If you scan to the right side of the nav bar, you'll see an icon showing a pair of overlapping rectangles, a grey one in front of a white one. This is called the counterpart icon. Click on it to switch between a .m and its corresponding .h file. For example, click the counterpart icon to switch to SKTGraphic.h. Note that the left arrow on the left side of the nav bar is now enabled. You can click it to go back to the file SKTGraphic.m. And, as you'd expect, once you click on the left arrow, the right arrow will be enabled so you can go back to SKTGraphic.h. As promised, just like the arrows in your browser.

As you visit different files in your editor window, they are added to a list, sort of a running history. Immediately to the right of the arrows in your nav bar is a popup listing all the files in this history list. Select a file name and the editor edits that file. Makes sense. The tiny dogear icon immediately to the left of the file name is a dirty flag. If the file is dirty (if it has changed since the last save) the icon is grey. Save the file and it returns to white.

Just to the right of the file name is a colon (":") followed by the current line number (either the beginning of a selection, or the line holding the insertion point). If you want to go to a specific line in a file, you can trial and error it, clicking around using the line number in the nav bar to help you home in on the right line. Or you can select Go to Line... from the Find menu (Command-L) and use that interface to select a specific line or range of lines (See Figure 5).


Figure 5. The Go to Line... command from the Find menu.

Also in the nav bar, just to the right of the file popup menu, lies the function/method popup. As you'd expect, this popup lists all the functions in the current file. Click anywhere inside a function and that function is shown in the popup title. Click on the popup and all the functions/methods in the file are listed in the order in which they appear. Option-click and the functions are listed in alphabetical order, separated by implementation. Give it a try. You'll get it right away.

Next over to the right is the counterpart icon (which we discussed above) followed immediately by the included files popup (it looks like a #) which lets you edit the tree of included files. Figure 6 shows the included files popup for SKTGraphic.m.


Figure 6. The included files popup menu.

To the lower right of the included files popup (at the top of the scroll bar) is the split view toggle. Click on the toggle to create a split in the editing window. Click the toggle again to remove the split. Once you create a split, the split resize control appears between the upper and lower scroll bars. To move the split, just drag this control (See Figure 7). Note that in the current Jaguar release (and presumably the only Jaguar release) of Xcode, the split resize control does not get drawn when you first create a split. Just resize the window a tiny bit and the control will appear.


Figure 7. Dragging the split resize control.

Fix and Continue

One of my favorite Xcode features is Fix-and-Continue. With Mac OS X's built-in support for dynamic linking, you can actually modify your code while it is running and watch the change come to life. Really.

So let's try this out. When you played with Sketch earlier in the column, you dragged out a rectangle and saw that the result was unfilled. If you look through the source code, you'll find that the fill color is white, but the setDrawFill: method is called with the parameter NO. In SKTGraphic.m, here's the init method:

- (id)init {
    self = [super init];
    if (self) {
        _document = nil;
        [self setBounds:NSMakeRect(0.0, 0.0, 1.0, 1.0)];
        [self setFillColor:[NSColor whiteColor]];
        [self setDrawsFill:NO];
        [self setStrokeColor:[NSColor blackColor]];
        [self setDrawsStroke:YES];
        [self setStrokeLineWidth:1.0];
        _origBounds = NSZeroRect;
        _gFlags.manipulatingBounds = NO;
    }
    return self;
}

Pay special attention to lines 6 and 7, which correspond to lines 20 and 21 in the file. If you haven't already, launch Sketch in the debugger. You can click on the Debug spray can in the editing window or debug window's toolbar, or select from the hammer/spraycan icon in the Project Window's toolbar.

Once Sketch launches in debug mode (you can tell the debugger is active because the Terminate and Pause icons will be enabled in the Debug window), drag out a couple of rectangles, just to prove that they are, indeed, unfilled.

Now go back to your editing window for SKTGraphic.m and change line 20 and 21 from:

        [self setFillColor:[NSColor whiteColor]];
        [self setDrawsFill:NO];

to:

        [self setFillColor:[NSColor greenColor]];
        [self setDrawsFill:YES];

Do NOT save. You'll see why in a sec.

Basically, we've changed the fill color from white to green and we've told Sketch that we do want our shapes filled.

Now comes the cool part.

Select Fix from the Debug menu.

Remember not to save!

You'll see a message in the Debug window about compiling and building. Once that settles down, go back to the running Sketch and click and drag out a rectangle. Wait, I've done it for you. Check out Figure 8. As you were expecting, the rectangles are now filled and green.


Figure 8. After the fix is applied, our rects are filled with green. Cool!

Once you are done playing with your new green rects, quit Sketch and rerun it, either as a straight run or via the debugger. Notice that your rectangles are back to being unfilled (you did remember to not save your changes, right?) To me, this is a beautiful way to play with your code. You can make changes, experiment, use Debug/Fix to test out your changes, see what works for you, then save what you want to.

I find dynamic linking fascinating. Fix and Continue works for Objective C, Carbon/C++ or even straight C, so it's available to all Mac OS X APIs and development languages. Though the Xcode team did not create dynamic linking, they did an excellent job rolling it into the environment. Brilliant!

    You may have noticed a scotch-tape dispenser icon in the Debug window with the label Fix. Clicking this icon does the same thing as selecting Fix from the Debug menu. There is a bug (I believe it is fixed in the current Panther release) where the icon is disabled (it just beeps when you click it). Fortunately, the bug does not affect the Fix item in the Debug menu.

Till Next Month...

Whelp, I'm out of space again. <sigh>. There's so much more I want to talk about. Next month, we're going to take the debugger through its paces and we'll also play around with a feature called code completion, one of my very favorite parts of Xcode. See you then...


Dave Mark is a long-time Mac developer and MacTech contributor. Author of more than a dozen books on various Mac-development topics, Dave is all about Xcode these days. Last month's column focused on the basics of opening a Project Builder project, target conversion, and the project window user interface. This month's installment will focus on the editor interface and a demo of fix-and-continue.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

NetShade 6.3.1 - Browse privately using...
NetShade is an anonymous proxy and VPN app+service for Mac. Unblock your Internet through NetShade's high-speed proxy and VPN servers spanning seven countries. NetShade masks your IP address as you... Read more
Dragon Dictate 4.0.7 - Premium voice-rec...
With Dragon Dictate speech recognition software, you can use your voice to create and edit text or interact with your favorite Mac applications. Far more than just speech-to-text, Dragon Dictate lets... Read more
Persecond 1.0.2 - Timelapse video made e...
Persecond is the easy, fun way to create a beautiful timelapse video. Import an image sequence from any camera, trim the length of your video, adjust the speed and playback direction, and you’re done... Read more
GIMP 2.8.14p2 - Powerful, free image edi...
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
Sandvox 2.10.2 - Easily build eye-catchi...
Sandvox is for Mac users who want to create a professional looking website quickly and easily. With Sandvox, you don't need to be a Web genius to build a stylish, feature-rich, standards-compliant... Read more
LibreOffice 5.0.1.2 - Free, open-source...
LibreOffice is an office suite (word processor, spreadsheet, presentations, drawing tool) compatible with other major office suites. The Document Foundation is coordinating development and... Read more
f.lux 36.1 - Adjusts the color of your d...
f.lux makes the color of your computer's display adapt to the time of day, warm at night and like sunlight during the day. Ever notice how people texting at night have that eerie blue glow? Or wake... Read more
VirtualBox 5.0.2 - x86 virtualization so...
VirtualBox is a family of powerful x86 virtualization products for enterprise as well as home use. Not only is VirtualBox an extremely feature rich, high performance product for enterprise customers... Read more
File Juicer 4.43 - Extract images, video...
File Juicer is a drag-and-drop can opener and data archaeologist. Its specialty is to find and extract images, video, audio, or text from files which are hard to open in other ways. In computer... Read more
Apple MainStage 3.2 - Live performance t...
MainStage 3 makes it easy to bring to the stage all the same instruments and effects that you love in your recording. Everything from the Sound Library and Smart Controls you're familiar with from... Read more

ReBoard: Revolutionary Keyboard (Utilit...
ReBoard: Revolutionary Keyboard 1.0 Device: iOS Universal Category: Utilities Price: $1.99, Version: 1.0 (iTunes) Description: Do everything within the keyboard without switching apps! If you are in WhatsApp, how do you schedule a... | Read more »
Tiny Empire (Games)
Tiny Empire 1.1.3 Device: iOS Universal Category: Games Price: $2.99, Version: 1.1.3 (iTunes) Description: Launch cannonballs and blow tiny orcs into thousands of pieces in this intuitive fantasy-themed puzzle shooter! Embark on an... | Read more »
Astropad Mini (Productivity)
Astropad Mini 1.0 Device: iOS iPhone Category: Productivity Price: $4.99, Version: 1.0 (iTunes) Description: *** 50% off introductory price! ​*** Get the high-end experience of a Wacom tablet at a fraction of the price with Astropad... | Read more »
Emo Chorus (Music)
Emo Chorus 1.0.0 Device: iOS Universal Category: Music Price: $1.99, Version: 1.0.0 (iTunes) Description: Realistic Choir simulator ranging from simple Chorus emulation to full ensemble Choir with 128 members. ### introductory offer... | Read more »
Forest Spirit (Games)
Forest Spirit 1.0.5 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.5 (iTunes) Description: | Read more »
Ski Safari 2 (Games)
Ski Safari 2 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: The world's most fantastical, fun, family-friendly skiing game is back and better than ever! Play as Sven's sister Evana, share... | Read more »
Lara Croft GO (Games)
Lara Croft GO 1.0.47768 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.47768 (iTunes) Description: Lara Croft GO is a turn based puzzle-adventure set in a long-forgotten world. Explore the ruins of an ancient... | Read more »
Whispering Willows (Games)
Whispering Willows 1.23 Device: iOS Universal Category: Games Price: $4.99, Version: 1.23 (iTunes) Description: **LAUNCH SALE 50% OFF** - Whispering Willows is on sale for 50% off ($4.99) until September 9th. | Read more »
Calvino Noir (Games)
Calvino Noir 1.1 Device: iOS iPhone Category: Games Price: $3.99, Version: 1.1 (iTunes) Description: The film noir stealth game. Calvino Noir is the exploratory, sneaking adventure through the 1930s European criminal underworld.... | Read more »
Angel Sword (Games)
Angel Sword 1.0 Device: iOS Universal Category: Games Price: $6.99, Version: 1.0 (iTunes) Description: Prepare to adventure in the most epic full scale multiplayer 3D RPG for mobile! Experience amazing detailed graphics in full HD.... | Read more »

Price Scanner via MacPrices.net

Big Grips Lift Handle For iPad Air and iPad A...
KEM Ventures, Inc. which pioneered the extra-large, super-protective iPad case market with the introduction of Big Grips Frame and Stand in 2011, is launching Big Grips Lift featuring a new super-... Read more
Samsung Launches Galaxy Tab S2, Its Most Powe...
Samsung Electronics America, Inc. has announced the U.S. release of the Galaxy Tab S2, its thinnest, lightest, ultra-fast tablet. Blending form and function, elegant design and multitasking power,... Read more
Tablet Screen Sizes Expanding as iPad Pro App...
Larger screen sizes are gaining favor as the tablet transforms into a productivity device, with shipments growing 185 percent year-over-year in 2015. According to a new Strategy Analytics’ Tablet... Read more
Today Only: Save US$50 on Adobe Elements 13;...
Keep the memories. lose the distractions. Summer’s winding down and it’s time to turn almost perfect shots into picture perfect memories with Elements 13. And get the power to edit both photos and... Read more
1.4GHz Mac mini on sale for $449, save $50
Best Buy has the 1.4GHz Mac mini on sale for $50 off MSRP on their online store. Choose free shipping or free local store pickup (if available). Price for online orders only, in-store price may vary... Read more
12-inch 1.1GHz Gold MacBook on sale for $1149...
B&H Photo has the 12″ 1.1GHz Gold Retina MacBook on sale for $1149.99 including free shipping plus NY sales tax only. Their price is $150 off MSRP, and it’s the lowest price available for this... Read more
27-inch 3.3GHz 5K iMac on sale for $1849, sav...
Best Buy has the 27″ 3.3GHz 5K iMac on sale for $1849.99. Their price is $150 off MSRP, and it’s the lowest price available for this model. Choose free shipping or free local store pickup (if... Read more
Worldwide Tablet Shipments Expected to Declin...
Does Apple badly need a touchscreen convertible/hybrid laptop MacBook? Yes, judging from a new market forecast from the International Data Corporation (IDC) Worldwide Quarterly Tablet Tracker, which... Read more
Continued PC Shipment Shrinkage Expected Thro...
Worldwide PC shipments are expected to fall by -8.7 percent in 2015 and not stabilize until 2017, according to the latest International Data Corporation (IDC) Worldwide Quarterly PC Tracker data. The... Read more
Imminent iPhone 6s Announcement Leads To 103%...
NextWorth Solutions, with its online and in-store electronics trade-in programs including http://NextWorth.com, reports that it has experienced a 103 percent surge in quoted trade-in values over the... Read more

Jobs Board

*Apple* Retail Online Store: Customer Insigh...
**Job Summary** Apple Retail (Online Store) is seeking an experienced e-commerce analytics professional to join the Customer Insights Team. The Web e-Commerce Analyst Read more
*Apple* Music, Business Operations - Apple I...
Changing the world is all in a day039s work at Apple . If you love innovation, here039s your chance to make a career of it. You039ll work hard. But the job comes with Read more
WW *Apple* Retail Online Store: Customer In...
**Job Summary** The Apple Retail - Online Store is seeking an experienced web merchandising analytics professional to join the Customer Insights Team. The Web Read more
Senior Payments Security Manager - *Apple*...
**Job Summary** Apple , Inc. is looking for a highly motivated, innovative and hands-on senior payments security manager to join the Apple Pay security team. You will Read more
Software QA Engineer, *Apple* Pay Security...
**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
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.