Objective-C

I have studied objective-C over the past few days and briefly talked about my understanding and views on its memory management mechanism. If you have any ideas or different opinions, I can share them with you, first, objective-C uses the reference

In objective-C, the real implementation of message and method is bound in the execution phase, rather than the compilation phase. The compiler converts the message to the call of the objc_msgsend method.The objc_msgsend method contains two required

// 聊聊NSNumber， NSNumber可以封装c中基本数据类型 char，int，long，float，BOOL，NSInteger，CGFloat等。 NSNumber *num = [NSNumber numberWithChar:'a']; NSLog(@"%@", num); // 97 num = [NSNumber numberWithInteger:97]; num = [NSNumber numberWithFloat:97.0];

// 1. 声明一个NSString对象，注意对象前要加‘*’； NSString *string1; // 赋值方式1，初始化赋值； NSString *string2 = [[NSString alloc] initWithString: @"hello world!"]; // 赋值方式2； string1 = @"hello world!"; string2 =

Objective-C underlying data structure Objective-C underlying data structure Class Data StructureClass (pointer) Typedef struct objc_class * class;/* this is the data structure generated by the compiler for each class. This structure defines a class.

// Implement carparts // Implement carparts # import @ interface tire: nsobject @ end @ implementation tire-(nsstring *) Description {return (@ "I Am a tire. I last a while. ");} @ end @ Interface Engine: nsobject @ end @ implementation

I have had the basics of related programming languages. I believe that I understand the concepts of classes and objects in C ++/Java. I will not repeat it too much here. For the definition and method usage of classes in OC, OC defines a set of its

The attribute mechanism in objective-C 2.0 provides us with a convenient way to obtain and set instance variables. It can also be said that the attribute provides us with a default configurator and accesser implementation. Before learning the

// Date is converted to string + (nsstring *) datetostring :( nsstring *) formatter date :( nsdate *) Date {nsdateformatter * dateformatter = [[nsdateformatter alloc] init]; [dateformatter setdateformat: formatter]; return [dateformatter

Some methods of string usage:   1. Create a dictionary nsstring variable string, and nsmutablestring immutable string. They are both objective objects. Char * STR is an array of letters. 2. String formatting: stringwithformat, which is used to

Personally, I prefer to convert the delegate mode into the proxy mode. In other words, the first contact with the proxy mode is in Java, so it is essential to implement the modern rational mode and interface in Java. At that time, when I learned

1. nsdictionary and nsmutabledictionary   Nsdictionary dictionarywithobjectsandkeys :~, Nil Create a dictionary using a key-Value Pair and end with the NIL flag Nsdictionary initwithobjectsandkeys: Use Key-value pairs to initialize the dictionary,

? ? The notification is a simple analogy. the boss of the company sent a notification to the following employees, saying that the company will go public tomorrow and all departments should make preparations. After the notification is sent, each

Campare trap Nsstring has multiple compare related methods:-(Nscomparisonresult) Compare :( nsstring *) string;-(Nscomparisonresult) Compare :( nsstring *) string options :( nsstringcompareoptions) mask;-(Nscomparisonresult) Compare :( nsstring *)

  @ Interface... @ Property (atomicity, writability, memory management) ID name; @ endAtomicity: nonatomic, atomic default atomic writability: readwrite, readonly default readwrite memory management: Assign, retain, copy default assign default value:

The structures that are frequently used in objective-C include nsange, nspoint, nssize (cgsize), and nsrect. 1 nsange The prototype of nsange is typedef struct _NSRange { NSUInteger location; NSUInteger length; } NSRange; Nsmakerange

#import "AppDelegate.h"#import "Person.h"@implementation AppDelegate@synthesize managedObjectContext = _managedObjectContext;@synthesize managedObjectModel = _managedObjectModel;@synthesize persistentStoreCoordinator = _persistentStoreCoordinator;- (

Enum and typedef, two examples are shown in the two sections respectively, as shown below:Enum direction {north, south, east, west }; Typedef Enum {north, south, east, west} direction; I can't help wondering what are the differences between the

1. What is a protocol? 2. Description and use of protocols and categories   1. What is a protocol? In objective-C, multi-inheritance is not supported, that is, a class cannot have multiple parent classes, but OC provides similar implementation

Nsarray * stringarray = [nsarray arraywithobjects: @ "zhangsan", @ "Lisi", @ "wangjun", @ "Lanlan", @ "yangyi", @ "qianzhongshu ", @ "sunwukong", @ "wugang", nil]; Nsarray * sortedarray = [stringarray sortedarrayusingcomparator: ^