Learn Objective C on the Mac phần 4 pptx

... 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 ... bring up the menu, you can 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...

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 ... extension to the C language. @interface Circle says to the compiler, “Here comes the interface for a new class named Circle.” NOTE NSObject in the @interface line tells the...

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

... 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

... ever be cleaned up. Car’s dealloc won’t get called until the engine releases the car in its dealloc, and the engine’s dealloc won’t get called until car’s dealloc releases the Engine. They just ... 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, change name = @"C...

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

... 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 ... 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. The “dist...

Ngày tải lên: 12/08/2014, 20:22

... std::string. You can put pointers to Objective- C objects into C+ + objects. Since all Objective- C objects are dynamically allocated, you can’t have complete objects embedded in a class or declared on a stack. ... *piece[32]; } @end // SWChessBoard C+ + objects embedded in Objective- C objects, rather than having a pointer relationship, will have their constructors called whe...

Ngày tải lên: 12/08/2014, 20:22