Mac OS X developer's guide

579 Pages·2002·12.635 MB·English

by  Jesse Feiler

ecaferP
When the first Mac OS shipped with the first Macintosh com-
puter in 1984, the development environment was a Lisa com-
puter. No compilers existed on the first Macintosh computers
when they shipped. Much has changed in the almost two de-
cades since then. The first copies of Mac OS X shipped in the
spring of 2001 with compilers for C, C++, Objective-C, and Ja-
va. Apple's integrated development environment featuring
Project Builder and Interface Builder was also on the CD, and
third party products such as CodeWarrior were also available
from the first day.
Born into a mature development environment, Mac OS X pro-
vides new and exciting opportunities for developers of all
xxi
xxii . Preface
sorts to explore the possibilities of personal computing. This
book provides an introduction to those possibilities.
You will find the background of Mac OS X in Part I, including
the architectural features of Mac OS X along with introduc-
tions to its various languages and frameworks. Part II focuses
on developing projects: It explores Project Builder, Interface
Builder, development techniques, and issues related to pro-
viding help and packing your software. Part III looks closely
at code: It hones in on particular tasks that you need to do and
provides line-by-line analysis of the code you will use.
The book looks primarily at the Cocoa framework using its
two languages (Java and Objective-C) equally in the exam-
ples. A lot of space is also given to Carbon, the other major de-
velopment framework that is unique to Mac OS .X Examples
for Carbon are provided in C++.
There are two other significant development environments
that matter on Mac OS :X Java and UNIX. Both are covered ex-
tensively in other books, as they are not unique to Mac OS .X
It is important to note how easy it is to use both of them. In
particular, integration of UNIX command line processing is a
great opportunity for developers. Using the func-
s ys tem()
tion, you can add calls to the command line to any C-based
application (Objective-C, C++, or C). Thus, you can use the so-
phisticated interface development tools such as Interface
Builder to create a spiffy front-end to these critical UNIX-
based tools: That, in large part, is what Apple expects many
developers to do. The opportunities there are enormous, and
the amount of work involved for each one is low.
Major features of the new Aqua interface are dealt with: You
will find drawers and toolbars described, and the implemen-
tation code for them is provided. Services, too, are given a lot
of space, in view of the fact that they represent yet another
area in which individual developers can significantly lever-
age their own work and that of others.
Diary (cid:12)9 xxiii
Diary
This book refers to an actual program written using Cocoa in
both Java and Objective-C. Called Diary, it implements a basic
journal that can contain various entries and images. You can
download the application and the source code from http://
www.philmontmill.com (go to the Mac OS X area). The full
code is not repeated in this book, but major sections of it are
presented and annotated. These sections implement the func-
tionality that many Mac OS X applications use.
For common features that are not used in Diary (drawing, for
example), code from the Mac OS X Developer CD is used~
Sketch, in most cases.
Other Documentation and Developer Resources
Apple provides a great deal of documentation on its Web site,
on the Developer CD, and as printed materials that you can
purchase. Of particular interest are the Project Builder exam-
ples that are installed with Project Builder. The step-by-step
tutorials for Interface Builder and Project Builder walk you
through many of the processes described here.
In addition to the step-by-step tutorials that Apple provides
in several media, there also is definitive and encyclopedic
documentation of Mac OS X APIs available online and with
the Developer CD. As new features are added to the Mac OS
X APIs, sometimes the documentation lags behind the code a
little bit: If you do not find what you are looking for, check
back later.
Rather than duplicate Apple's documentation, this book at-
tempts to provide alternative perspectives in order to provide
a well-rounded view of the technology.
xxiv (cid:12)9 Preface
Apple's Web site is an essential resource for all developers.
Located at http://developer.apple.com, it provides sample
code, technical documentation in a variety of formats, and in-
formation about Apple and third-party resources including
training, consulting, and publications.
In addition to the developer site, the support discussions at
http://www.apple.com/support can be of help to develop-
ers. Sections devoted to developers contain exchanges that
may provide you with information and tips; you can also post
your comments and questions there.
Mailing lists are available through http://www.lists.ap-
ple.com. These lists include announcements as well as discus-
sion lists of interest to developers, including lists devoted to
Project Builder, Cocoa, Carbon, and Java. Most of the lists are
managed by Apple, but some third-party lists are also includ-
ed.
Finally, the author's Web site at http://www.philmont-
mill.com contains a section devoted to Mac OS .X It provides
a question and answer forum as well as a section with post-
ings of information relevant to Mac OS .X
stnemgdelwonkcA
Many people have contributed to this book. At Morgan Kauf-
mann in San Francisco, Tim Cox and Stacie Pierce provided
strong editorial guidance, while Mei Levenson and Laurie
Anderson did great work on designing the cover. Sheri
Dean's help on marketing is always terrific. In Boston at Aca-
demic Press, Julie Bolduc, production editor, and Jill Hobbs,
copy editor, worked wonders with a very complex manu-
script and a very tight deadline.
Notwithstanding the assistance of all of these people, any er-
rors that remain are the author's handiwork alone.
xxiv (cid:12)9 Preface
Apple's Web site is an essential resource for all developers.
Located at http://developer.apple.com, it provides sample
code, technical documentation in a variety of formats, and in-
formation about Apple and third-party resources including
training, consulting, and publications.
In addition to the developer site, the support discussions at
http://www.apple.com/support can be of help to develop-
ers. Sections devoted to developers contain exchanges that
may provide you with information and tips; you can also post
your comments and questions there.
Mailing lists are available through http://www.lists.ap-
ple.com. These lists include announcements as well as discus-
sion lists of interest to developers, including lists devoted to
Project Builder, Cocoa, Carbon, and Java. Most of the lists are
managed by Apple, but some third-party lists are also includ-
ed.
Finally, the author's Web site at http://www.philmont-
mill.com contains a section devoted to Mac OS .X It provides
a question and answer forum as well as a section with post-
ings of information relevant to Mac OS .X
stnemgdelwonkcA
Many people have contributed to this book. At Morgan Kauf-
mann in San Francisco, Tim Cox and Stacie Pierce provided
strong editorial guidance, while Mei Levenson and Laurie
Anderson did great work on designing the cover. Sheri
Dean's help on marketing is always terrific. In Boston at Aca-
demic Press, Julie Bolduc, production editor, and Jill Hobbs,
copy editor, worked wonders with a very complex manu-
script and a very tight deadline.
Notwithstanding the assistance of all of these people, any er-
rors that remain are the author's handiwork alone.
Part I
Introducing Mac OS X
Mac OS X, the new operating system from Apple Computer, si built
no firm foundations. These include the principles of modern operat-
ing systems (including multithreading, multiprocessing, a UNIX-
desab kernel, and memory protection) sa well sa object-oriented pro-
gramming and component software.
This part of the book provides a summary of the Mac OS X architec-
ture, sa well sa the principles of modern operating systems and -bo
ject-oriented programming.
Chapter I
Introduction
Mac OS X is a departure from previous operating systems both on
mainframes and on personal computers. Its structure is thoroughly
modern~it is based on a small kernel that isolates the most critical
aspects of the operating system, and it is object oriented to a degree
that has not been seen in a mainstream operating system. Its user ex-
perience has been developed based not only on Apple's years of re-
search and development in this area, but also on the powerful
processors of today and tomorrow that can provide a rich, sophisti-
cated, and delightful user experience of greater elegance and power
than their earlier incarnations could provide.
This book is for Mac OS X developers~for people who are starting
to explore Mac OS X to find out what's there and what the opportu-
4 (cid:12)9 Chapter I" Introduction
nities are. It is about writing software and about how Mac OS X
makes the developer's job much easier---and very different.
Writing computer software can eb very rewarding~both intellectu-
ally and financially. Yet it requires scrupulous attention to detail
and often consists of continuing repetitions of nearly similar tasks~
tasks that must eb carried out with attention and accuracy, despite
their likenesses. Errors can cause immediate problems, or they can
eil in wait until a particular combination of circumstances conspires
to loose their destructive forces on unsuspecting people.
The work is extraordinarily labor intensive, consuming large
amounts of the lives of often highly paid people while requiring them
to repeat (not mindlessly but )yllufdnim the same tasks over and
over, at the same time exacting high prices for even the slightest
flaws or inattention to these complex, repetitive processes.
For nearly 50 years, people have looked at the process of program-
ming computers and tried to improve it. The impetus for these at-
tempts comes from programmers themselves as well as from their
managers. Management, of course, would like to reduce costs, im-
prove the reliability of code, and produce software more quickly.
These incentives era nothing compared to the goals of program-
mers~people who find themselves writing sort routines, natural
language parsers, report formatters, and mouse-tracking procedures
over and over and over again. Each version is almost like the last
one--similar enough to pose little imaginative challenge, yet differ-
ent enough to eb riddled with snares for the inattentive.
Meanwhile, the nature of computer software has been changing,
with the focus moving from mainframes to personal computers and
then to networks of machines. As the nature of software has changed,
enormous advances in hardware (processing speed, memory, and
storage) coupled with dramatic decreases in their costs have allowed
developers to experiment with new techniques that previously
would have been impractical to implement.
This chapter addresses three basic issues that era at the core of Mac
OS X development:
(cid:12)9 Who is a programmer?
Who Is a Programmer? (cid:12)9 5
(cid:12)9 The search for better ways to write software
(cid:12)9 The evolution of software
Far from being abstract historical issues, these are at the core of the
developer tools and experience in Mac OS X.
Who Is a Programmer?
Traditionally, there has been an enormous barrier between
programmers and software users. With Mac OS ,X that barrier
is being broken down; in fact, it has been wobbling for some
time now. The concept of power users or advanced users has
been around for ages: Macros, Visual Basic scripts, Apple-
Script scripts, and the like are typically written by these peo-
ple. Programs that need compilation, however, have been the
province of programmers. True, some power users have ex-
perimented with them, but by and large, they have stayed
away.
With Mac OS ,X the range of programming tools is vast: it
ranges from the command line that is available in Terminal,
through scripting technologies such as AppleScript and Perl,
and on to services (which allow for the construction of very
customized programs and processes). Also, the development
tools~compilers, Project Builder, and Interface Builder~are
distributed with shrink-wrapped copies of Mac OS X and are
easily downloadable from Apple's developer site located at
(http://developer.apple.com). Apple is making it easier to
program, and it is making those tools more widely available.
The bulk of programming is done not for shrink-wrapped
products but for custom applications. Some of these are ex-
tremely tailored: one person writing code for private use. Oth-
ers are written for a particular environment (one school or
office) or for vertical markets (libraries, veterinarians, or
graphic artists).
6 (cid:12)9 Chapter I: Introduction
If you are wondering if you could possibly write a program,
worry no more: You can with Mac OS .X This book helps you
understand the concepts behind developing for Mac OS .X
The development tools that are on the Developer CD as well
as the tools and sample code on Apple's developer site
(www.apple.com/developer) are thorough and informative:
their information is not repeated here to any great extent.
The Search for Better Ways to Write Software
Perhaps more than the economic motives of management, the
sense among many programmers that they are wasting enor-
mous amounts of time repeating and repeating the same old
code has inspired a decades-long search for better ways to de-
velop software.
This search for better ways to write software has centered on
three primary areas:
(cid:12)9 The process of producing code
(cid:12)9 The reuse of existing code
(cid:12)9 The abstraction of code
Improving the In this strategy to improve the production of software, the fo-
Production of cus is on the actual production of code. Compilers and code
Code generators automate its production while techniques of cod-
ing such as structured programming improve the quality of
the code. Nontextual programmer tools bring the power of
graphical user interfaces to programmers (at last!).
srelipmoC dna leveL-hgiH segaugnaL Strange sa it may seem
today, the possibility of writing a compiler was not widely ac-
cepted in the early 1950s. Compilers and high-level languages
(starting with Fortran, Algol, and Cobol in the late 1950s) have
grown far beyond their early implementations.