OBJECTIVE-C Study Notes

OBJECTIVE-C Study Notes

1. Use #import Import header file, General OSX command line development using <foundation/foundation.h>, GUI development use <Cocoa/Cocoa.h>

The string in 2.OC is no longer an array, but instead becomes an object of type NSString, where the string is the object, and when the static string is assigned, you should use @ To do the identification, for example @ "HelloWorld"

3.OC is true and false bool type, while true yes false for no, accounting for eight bits, the system relies on the lowest bit to determine, the lowest bit is 0 for no, the lowest bit is not zero, is yes, so, when compared with bool, should compare with no

4./tmp is the system cache directory, the system restarts when the time is emptied

The 5.id type is a generic pointer to OC, which can point to any object, but it is best not to misuse

The interface definition mode for 6.OC is as follows

@interface

{

The @ property's access rights

Property value

}

-(return type of method) method name: (type of parameter 1) parameter name, (type of parameter two) argument name;

@end

The 7.OC interface is implemented as follows

@implemention

-(return type of method) method name: (type of parameter 1) parameter name (type of parameter two) argument name

{

function Implementation/method implementation

}

@end

The 8.OC call method uses brackets, such as [instance pointer method name: Parameter 1, parameter 2]

9. In the implementation of the class, the instance variable of the class can be accessed directly, because the OC compiler hides a parameter self when directly accessing it.

10. The simplest way to generate a new instance is [class name new] (not recommended later)

11,OC itself does not support multiple inheritance, but it can be implemented with a delegation mechanism to implement multiple inheritance

12. A method in a subclass that wants to invoke the parent class can use the Super keyword, for example [Super init]

13. When defining an interface, you can specify the inherited parent class, as in the following example

@interface Interface Name: Parent class name

@end

14. Use NSLog to output, similar to printf

15.NSLog can print the object, adapt to the%@ parameter, so the system will automatically call the object's description method

16. The method of accessing the property, using the set+ attribute name method to use the property name directly, assuming that the property is xxx;

-(void) SETXXX: (id) XXX-(id) xxx;

17.oc uses the. m format of the source file and the. h format header file, which is usually stated in the. h file, implemented in the. m file

[email protected] class Name This keyword generally represents the import class, which is used in the. h file when you do not want to include the header file when you Use the keyword

19. Scope structure Body Nsrange, indicating the starting point and size of the number, the parameters are unsigned shaping, the assignment has function nsmakerange () function

20. Coordinate structure body cgpoint, parameters are floating point type, representing coordinates, Cgpointmake fast assignment

Graphical structure Body cgsize parameter is floating point, cgsizemake fast Assignment

The rectangular structure CGRect contains two structure-type parameters and is quickly assigned to CGRectMake

21. Methods of String class NSString

stringWithFormat creating a new string

Length gets the number of strings

Isequaltostring string comparison

Compare string comparison

Nscompareresult comparison structure enumeration, value including Nsorderascending, etc. three

Hasprefix detects whether a string begins with a specified string

Hassuffix detects whether a string ends with a specified string

Rangeofstring detects if there is a specified string in the string that does not return Nsrange in location is Nsnotfound

22.NSString is immutable at run time and requires nsmuteablestring if run-time variable strings are required

Stringwithcapacity specifying the capacity of initialization

AppendString additional substrings

AppendFormat attaching a formatted string

Deletecharactersinrange Delete a character at a specified position in a string

Because Nsmuteablestring is a subclass of NSString, NSString's function nsmuteablestring can be used

22.NSArray

Nsarray can be placed in any type of object, but cannot hold native data types

Arraywithobjects initialization, specifying the original list of data

Count gets the number of elements

Objectatindex getting elements of a specific location

Componentsjoinedbystring uses a specific string to link all elements into a new string to return

22, variable group Nsmutablearray

Arraywithcapacity specifying the capacity of initialization

AddObject adding objects at the end

Removeobjectatindex removing elements from a specified position

Objectenumerator getting an enumerator for an array object

23. Enumerations, using enumerators

while (id thing = [enum Nextobject])

{

//dosomething

}

24. Quick Enumeration

New features after 10.5, while (nsstring* str in array) {//dosomething}

25.NSDictionary Dictionary

Dictionarywithobjectsandkeys creating a key-value pair, initializing the object

Objectforkey getting objects by key

26. Variable Dictionary nsmutabledictionary

Dictionarywithcapacity Initializing a mutable dictionary, specifying the capacity

SetObject Forkey Adding key-value pairs

Removeobjectforkey Delete a key-value pair

27. For NSString and Nsarray, do not inherit, preferably using composite

28.NSNumber Numerical class

Used to boxing native data types

Numberwithchar numberwithint numberwithfloat Numberwithbool Boxing

Charvalue intvalue floatvalue boolvalue stringvalue Unpacking

29.NSNumber is actually a subclass of Nsvalue, Nsvalue can encapsulate any value,

Valuewithbytes specify data length and data type to be boxed

GetValue for extracting values

30.NSNull

Nil boxed data structure, only one method null

The 31.oc method is divided into two types, the instance method and the class method, the use of-defined is the instance method uses the + definition method is the class method, the class method can be called directly through the class name when there is no instance, such as the Init method, as follows

Class method +void init: (int) A, (int) b;

Instance method-void init: (int) A, (int) b;

OBJECTIVE-C Study Notes