Objective-c - @property的参数

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1> 回顾@property的功能:

1,自动生成私有的带下划线的属性;

2,自动的生成这个属性的setter/getter方法的声明;

3,自动的生成这个属性的setter/getter方法的实现;

setter的实现,直接赋值;getter的实现,直接返回.

注意: 生成的是不含内存管理代码的setter方法.

2> @property的参数:@property可以带参数,带不同的参数可以实现不同的功能.

语法:@property(参数1,参数2,...)数据类型数据名称;

1,与多线程相关的参数

atomic :默认值.生成的setter/getter方法是很安全的方法,安全但是性能低下.

nonatomic:生成的setter/getter方法不安全,但是效率高.

(注意:推荐使用nonatomic,不写的话默认是atomic).

2,与生成setter方法实现相关的参数

assign:默认值.如果使用assign,生成的setter方法的实现中,就是直接将参数的值赋值给属性.

retain:生成的setter方法中,是标准的MRC内存管理代码.如下:(以YYCar *_car为例)

- (void)setCar:(YYCar *)car

{

if(_car != car)

{

[_car release];

_car = [car retain];

}

(当属性的类型是oc对象的时候,就使用retain.当属性的类型是非oc对象的时候,就使用assign).

(但是并不会在dealloc中也生成release代码,所以dealloc中的release需要自己去写).

3,与生成只读,读写封装相关的参数

readwrite:默认值.同时生成setter/getter方法.

readonly:值生成getter方法,不生成setter.

4,与指定生成的setter/getter方法的名称相关的参数

setter:可以指定生成的setter方法的名称;

语法:setter = abc,即生成的setter方法的名称是abc,即: - (void)abc:(YYCar *)car;

getter:可以指定生成的getter方法的名称;

语法:getter = abc,即生成的getter方法的名称是abc,即: - (YYCar *)abc;

只有当属性的类型是BOOL类型的时候,我们可以修改getter方法的名称,以提高代码的阅读性:

例:@property(getter = isGoodMan) BOOL goodMan;

例:YYPerson *xiaoming = [YYPerson new];

xiaoming.goodMan = YES;

NSLog(@"%d", xiaoming.isGoodMan):

注意:参数的顺序没有要求,同一组参数不可以同时使用.

#import <Foundation/Foundation.h>

#pragma mark -

#pragma mark 车类的创建

//声明

@interface YYCar : NSObject

@property(nonatomic,retain)NSString *brand;

@property(nonatomic,assign)int speed;

- (void)run;

//自定义构造方法

- (instancetype)initWithBrand:(NSString *)brand;

- (instancetype)initWithBrand:(NSString *)brand andSpeed:(int)speed;

+ (instancetype)carWithBrand:(NSString *)brand;

+ (instancetype)carWithBrand:(NSString *)brand andSpeed:(int)speed;

@end

//实现

@implementation YYCar

//重写dealloc方法,监视车对象的回收

- (void)dealloc

{

NSLog(@"%@释放了!",_brand);

[super dealloc];

}

- (void)run

{

NSLog(@"%@在行驶!",_brand);

}

//自定义构造方法

- (instancetype)initWithBrand:(NSString *)brand

{

if(self = [superinit])

{

self.brand = brand;

}

return self;

}

- (instancetype)initWithBrand:(NSString *)brand andSpeed:(int)speed

{

if(self = [superinit])

{

self.brand = brand;

self.speed = speed;

}

return self;

}

+ (instancetype)carWithBrand:(NSString *)brand

{

return [[selfalloc]initWithBrand:brand];

}

+ (instancetype)carWithBrand:(NSString *)brand andSpeed:(int)speed

{

return [[selfalloc]initWithBrand:brandandSpeed:speed];

}

@end

#pragma mark -

#pragma mark 人类的创建

//声明

@interface YYPerson : NSObject

@property(nonatomic,retain)NSString *name;

@property(nonatomic,retain)YYCar *car;

@property(nonatomic,assign,getter=isGoodMan)BOOL goodMan;

- (void)drive;

//自定义构造方法

- (instancetype)initWithName:(NSString *)name;

- (instancetype)initWithName:(NSString *)name andCar:(YYCar *)car;

- (instancetype)initWithName:(NSString *)name andCar:(YYCar *)car andDoodMan:(BOOL)goodMan;

+ (instancetype)personWithName:(NSString *)name;

+ (instancetype)personWithName:(NSString *)name andCar:(YYCar *)car;

+ (instancetype)persontWithName:(NSString *)name andCar:(YYCar *)car andDoodMan:(BOOL)goodMan;

@end

//实现

@implementation YYPerson

//重写dealloc方法,监视人对象的回收

- (void)dealloc

{

NSLog(@"%@释放了",_name);

[_car release];

[super dealloc];

}

- (void)drive

{

NSLog(@"%@开去上学",_name);

[_car run];

}

//自定义构造方法

- (instancetype)initWithName:(NSString *)name

{

if(self = [superinit])

{

self.name = name;

}

return self;

}

- (instancetype)initWithName:(NSString *)name andCar:(YYCar *)car

{

if(self = [superinit])

{

self.name = name;

self.car = car;

}

return self;

}

- (instancetype)initWithName:(NSString *)name andCar:(YYCar *)car andDoodMan:(BOOL)goodMan

{

if(self = [superinit])

{

self.name = name;

self.car = car;

self.goodMan = goodMan;

}

return self;

}

+ (instancetype)personWithName:(NSString *)name

{

return [[selfalloc]initWithName:name];

}

+ (instancetype)personWithName:(NSString *)name andCar:(YYCar *)car

{

return [[selfalloc]initWithName:nameandCar:car];

}

+ (instancetype)persontWithName:(NSString *)name andCar:(YYCar *)car andDoodMan:(BOOL)goodMan

{

return [[selfalloc]initWithName:nameandCar:car andDoodMan:goodMan];

}

@end

#pragma mark -

#pragma mark main函数

int main(int argc,const char * argv[]) {

//创建人对象

YYPerson *xiaoming = [YYPersonpersonWithName:@"小明"];

xiaoming.goodMan = YES;

NSLog(@"%@%@", xiaoming.name, xiaoming.goodMan ==YES?@"是一个好人":@"不是一个好人");

//创建车对象

YYCar *bz = [YYCarcarWithBrand:@"奔驰"andSpeed:120];

//将车对象赋值给人的车属性

xiaoming.car = bz;

[xiaoming drive];

[bz release];

[xiaoming release];

return 0;

}

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