【Objective-C学习-2】OC类

最新推荐文章于 2025-07-04 20:33:39 发布

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本文探讨了Objective-C与Swift两种编程语言在iOS开发领域的应用与区别，包括其优势、特性和最佳实践，旨在帮助开发者选择合适的语言进行项目开发。

一、类的声明 //Person.h

#import <Foundation/Foundation.h>

@interface Person : NSObject {
    /*成员变量声明在类的内部
     *成员变量默认可访问属性为 @Protected
     *OC中自定义的类或系统类对象都必须是一个指针
     */
    NSString *_name;
    NSString *_no;
    int _age;
}

//+ 表示静态方法
+ (id)personWithName:(NSString *)name;

//- 表示动态方法
- (id)initWithName:(NSString *)name;

//get方法
- (NSString *)name;

//set方法，方法名是 setName:
- (void)setName:(NSString *)name;

- (NSString *)no;
- (void)setNo:(NSString *)no;

//方法名是 setName:andNo:
- (void)setName:(NSString *)name andNo:(NSString *)no;

- (int)age;
- (void)setAge:(int)age;

@end

二、类的实现 //Person.m

#import "Person.h"

@implementation Person

+ (id)personWithName:(NSString *)name {
    return [[[self alloc] initWithName:name] autorelease]; //通过静态方法创建的对象，应该自动释放
}

- (id)init {
    return [self initWithName:nil];
}

- (id)initWithName:(NSString *)name {
    if (self = [super init]) {
        _name = [name copy];
    }
    return self;
}

- (void)dealloc {
    [super dealloc];
    NSLog(@"Person dealloc");
}

- (NSString *)name {
    return _name;
}

- (void)setName:(NSString *)name {
    _name = [name copy];
}

- (NSString *)no {
    return _no;
}

- (void)setNo:(NSString *)no {
    _no = [no copy];
}

- (void)setName:(NSString *)name andNo:(NSString *)no {
    _name = [name copy];
    _no = [no copy];
}

- (int)age {
    return _age;
}

- (void)setAge:(int)age {
    _age = age;
}

//重写父类的description方法
//当使用%@打印一个对象的时候调用
- (NSString *)description {
    NSString *str = [NSString stringWithFormat:@"My name is %@, my identify card's number is %@, and I am %d years old.", 
                     _name, _no, _age];
    return str;
}

@end

三、类的使用 //main.m

#import <Foundation/Foundation.h>
#import "Person.h"

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        
        Person *person = [Person personWithName:@"dave"]; //调用静态方法创建对象
        [person setNo:@"110001"];
        [person setAge:25];
    
        NSLog(@"My name is %@, my identify card's number is %@, and I am %d years old.",
              [person name], [person no], [person age]);
        
        Person *person2 = [[[Person alloc] init] autorelease]; //创建的时候指定autorelease，
                                                               //离开autoreleasepool的时候会自动释放
        [person2 setName:@"john" andNo:@"110002"];
        person2.age = 25; //OC点语法，等效于 [person2 setAge:25]
        
        int age = person2.age; //OC点语法，等效于 [person age]
        NSLog(@"My name is %@, my identify card's number is %@, and I am %d years old.",
              person2.name, person2.no, age);
        
        NSLog(@"%@", person2);
    }
    return 0;
}