Learn Objective C on the Mac phần 9 ppsx

... of namespaces. C+ + vtable vs. Objective- C Dynamic Dispatch One of the biggest differences between C+ + and Objective- C is the mechanism of dispatch- ing methods (or member functions, as they’re ... against each object of that collection, then turns the resulting values into a collection. The “union” part of the name refers to taking the union of a bunch of objects. T...

Ngày tải lên: 12/08/2014, 20:22

... that contains the code for Hello Objective- C. Hello Objective- C. m contains boilerplate code, kindly provided by Xcode for each new proj- ect. We can make our Hello Objective- C application a ... Hello Objective- C folder. To create the project, start by launching Xcode. You can find the Xcode appli- cation in /Developer/Applications. We put the Xcode icon in the Dock...

Ngày tải lên: 12/08/2014, 20:22

... soon become very important: ■ The interface is the description of the features provided by a class of objects. For example, the interface for class Circle declares that circles can accept the ... the data. Functions are the center of the procedural programming experience: you decide which functions you want to use, and then you call those functions, passing in the data t...

Ngày tải lên: 12/08/2014, 20:22

... you can construct a string that describes all sorts of information about the object, such as the fat content and calories for the cheese Danish. The description method for Cocoa’s NSArray class, ... which manages a collection of objects, provides informa- tion about the array itself, such as the number of objects it contains and descriptions of each object it contains. These des...

Ngày tải lên: 12/08/2014, 20:22

... with each method call. The compiler needs to see the entire contents of the class to correctly calculate the location of the instance variables. Next on the operating table is Slant6. Create the ... use control- period to cycle through the options or shift-control- period to cycle backward. Don’t worry if you don’t catch all the shortcuts as we go along. There’s a handy...

Ngày tải lên: 12/08/2014, 20:22

... characters adjacent to the cursor Control-D Delete the character to the right of the cursor Control-K Delete the line Control-L Center the cursor in the text editor ⌘⌥D Show the Open Quickly window ⌘⌥↑ Open ... class, it creates a class object that represents the class. The class object contains pointers to the superclass, class name, and to the list of the class’s...

Ngày tải lên: 12/08/2014, 20:22

... [SomeClass new], and the second is [[SomeClass alloc] init]. These two techniques are equivalent, but the common Cocoa convention is to use alloc and init rather than new. Typically, Cocoa programmers ... perform object allocation and initialization in a single operation using a constructor. Objective- C splits the two operations into explicit allocation and initialization stage...

Ngày tải lên: 12/08/2014, 20:22

... weirdness CHAPTER 12: Categories 2 19 Like the @interface for the category, the @implementation has the names of the class and the category, along with the bodies of the new methods. The lengthAsNumber ... variable, which has been changed. We can choose to do a search and replace on the name, or we can change direct ivar access to use accessors instead. In init, cha...

Ngày tải lên: 12/08/2014, 20:22

... car is allocated by sending allocWithZone: to the class of the object that’s receiving this message: Car *carCopy; carCopy = [[[self class] allocWithZone: zone] init]; CarParts-copy contains ... do the same thing, but this time, control- drag from the AppController to the Label, and choose the resultsField item to make that connection. Double-check your work by choosing...

Ngày tải lên: 12/08/2014, 20:22

... Inspector, 255 connecting AppController to the user interface controls, 252 connecting the UpperCase and LowerCase but- tons to the AppController, 260 Connections panel, 260 creating the AppController, ... 140 dependencies circular dependency, handling, 96 definition of, 93 forward reference, 96 handling cross-file dependencies, 94 limiting the effects of dependency-caused...

Ngày tải lên: 12/08/2014, 20:22