继承 初始化方法 遍历构造器

继承:

1.单向继承,一个类只能有一个父类,一个父类可以有多个子类.

2.单向继承,基类(根类)是OSObject

3.子类可以继承父类的属性和方法

当父类的方法不满足子类的需求时,子类可以重写父类的方法,重写父类的方法,在子类中不需要再次声明.

1.完全重写

2.部分重写 使用super

建立继承关系之后,子类可以继承父类的:

1.实例变量,@public@protected修饰情况之下

2.公开的方法

一个方法如果在.h中声明了,那么这个方法就是公开的方法,如果没有声明,则是私有的.

OC中没有绝对私有的方法.

子类调用方法的过程:

先在本类中寻找方法,如果找到就直接调用,如果没有找到就在其父类中寻找,如果在父类中也没有找到,就继续其次向上寻找(父类的父类),直到找到为止.

如果找不到就抛出异常,引起crash.

对象对对象可以赋值,对象就是指针.

自定义初始化方法不需要在.h文件中声明.因为是重写了该方法.

遍历构造器一定是一个类方法

返回值类型(id,instancetype)

都是声明变量 自定义减号需要声明变量 遍历构造器加号 不需要声明变量

自定义初始化方法:初始化+赋值.

便利构造器:开辟空间+初始化+赋值.

自定义初始化方法:

-(id)initWithColor:(NSString *)color

price:(NSString *)price{

if (self=[super init]) {

_price = price;

_color = color;

}

return self;

}

便利构造器:

+(id)appleWithColor:(NSString *)color

price:(NSString *)price{

Apple *apple=[[Apple alloc]initWithColor:color price:price];

return apple;

}

您好，写一个简单地便利构造器
+(Student *)studntWithName :(NSString *)aName  andAge:(int)anAge
{
Student *stu=[Student  alloc]initWithName :aName  andAge:anAge
return stu;
}

//1..h声明文件中
#import <Foundation/Foundation.h>
@interface Person :NSObject
{
NSString * name;//名字
int age;//年龄
}
@property (assign,nonatomic) NSString * name;//声明名字访问属性
@property (assign,nonatomic) int age;//声明年龄访问属性
-(id)initWith:(NSString *)newName  withAge:(int)newAge;//声明构造函数
-(void)sayhi;//打招呼方式
@end

//2..m实现文件中
@implementation Person
@synthesize name;//实现name属性
@synthesize age;//实现age属性
-(id)initWith:(NSString *)newName  withAge:(int)newAge;//实现构造函数
{
self =[super init];//调用父类super init方法
if(self)
{
[self setName:newName];另一种调用方法 self.name:newName;
[self setAge:newAge];//另一种调用方法 self.Age:newAge;
}
return self;
/*构造函数一般书写方式:
self =[super init];
if(self)
{
　　　　函数体
}
return self;
*/
}

-(void)sayhi
{
NSLog(@"hi,My name is %@,I'm %d old!",name,age);
}
@end

//3.主函数中
#import <Person.h>
int main(int argc, const char * argv[])
{
Person * xiaozhang=[[Person alloc]initWith:@"小张" withAge:25];//构造函数调用
[xiaozhang sayhi];//调用sayhi方法
return 0;
}

写一个简单地便利构造器

+(Student *)studntWithName :(NSString *)aName  andAge:(int)anAge
{
Student *stu=[Student  alloc]initWithName :aName  andAge:anAge
return stu;
}

//1..h声明文件中
#import <Foundation/Foundation.h>
@interface Person :NSObject
{
NSString * name;//名字
int age;//年龄
}
@property (assign,nonatomic) NSString * name;//声明名字访问属性
@property (assign,nonatomic) int age;//声明年龄访问属性
-(id)initWith:(NSString *)newName  withAge:(int)newAge;//声明构造函数
-(void)sayhi;//打招呼方式
@end

//2..m实现文件中
@implementation Person
@synthesize name;//实现name属性
@synthesize age;//实现age属性
-(id)initWith:(NSString *)newName  withAge:(int)newAge;//实现构造函数
{
self =[super init];//调用父类super init方法
if(self)
{
[self setName:newName];另一种调用方法 self.name:newName;
[self setAge:newAge];//另一种调用方法 self.Age:newAge;
}
return self;
/*构造函数一般书写方式:
self =[super init];
if(self)
{
　　　　函数体
}
return self;
*/
}

-(void)sayhi
{
NSLog(@"hi,My name is %@,I'm %d old!",name,age);
}
@end

//3.主函数中
#import <Person.h>
int main(int argc, const char * argv[])
{
Person * xiaozhang=[[Person alloc]initWith:@"小张" withAge:25];//构造函数调用
[xiaozhang sayhi];//调用sayhi方法
return 0;
}

//初始化方法

//形式:

//系统的:- (instanceType)init;

//自定义的: - (instanceType)initWithXXX(参数类型)参数名......

// Zombie *zombie = [[Zombie alloc]

// initWithName:@"wuye" hp:20 ap:2 speed:10];

// NSLog(@"%@", zombie.name);

//[zombie setName:@"wuye" ap:20 hp:2 speed:1];

//遍历构造器

//+ (instanceType)类名;

//+ (instanceType)类名WithXXX:(参数类型)参数......

BlockZombie *z = [BlockZombie
zombie];

z.name =
@"zahngyang";
自定义初始化方法

#import <Foundation/Foundation.h>

@interface Zombie :
NSObject

{

NSInteger _hp;//血量

NSInteger _ap;//攻击力

CGFloat _speed;//速度

NSString *_name;//名字

}

- (void)move;//移动

- (void)attack;//攻击

- (void)die;//死亡

-(void)setName:(NSString *)name;

- (NSString *)name;

- (void)setSpeed:(CGFloat )speed;

- (CGFloat )speed;

- (void)setAp:(NSInteger )ap;

- (NSInteger )ap;

- (void)setHp:(NSInteger )hp;

- (NSInteger )hp;

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

- (instancetype)initWithName:(NSString *)name hp:(NSString *)hp ap:(NSInteger )ap speed:(CGFloat
)speed;

@end

#import "Zombie.h"

@implementation Zombie

//自定义初始化方法

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

{

//1.调用从父类继承的init方法,作用:初始化从父类继承的成员变量

self = [super
init];

//2.self是否为空,

if (self) {

//3.如果self不是空,就给成员变量赋值

_name = name;

}

//4.

return self;

}

- (instancetype)initWithName:(NSString *)name hp:(NSInteger )hp ap:(NSInteger )ap speed:(CGFloat
)speed

{

self = [super
init];

if (self) {

_name = name;

_hp = hp;

_ap = ap;

_speed = speed;

}

return
self;

}

- (void)move

{

NSLog(@"fast");

}

- (void)attack

{

NSLog(@"strong");

}

- (void)die

{

NSLog(@"fast");

}

-(void)setName:(NSString *)name

{

_name = name;

}

- (NSString *)name

{

return _name;

}

- (void)setSpeed:(CGFloat )speed

{

_speed = speed;

}

- (CGFloat )speed

{

return _speed;

}

- (void)setAp:(NSInteger )ap

{

_ap = ap;

}

- (NSInteger )ap

{

return _ap;

}

- (void)setHp:(NSInteger )hp

{

_hp = hp;

}

- (NSInteger )hp

{

return _hp;

}

@end
建一个student类

#import <Foundation/Foundation.h>

@interface Student :
NSObject

@property NSString *name;

@property NSInteger age;

@property NSInteger number;

@property NSString *gender;

@property CGFloat score;

- (instancetype)initWithName:(NSString *)name Gender:(NSString *)gender Number:(NSInteger )number Age:(NSInteger
)age Score:(CGFloat )score;

+ (instancetype)studentWithName:(NSString *)name Gender:(NSString *)gender Number:(NSInteger )number Age:(NSInteger
)age Score:(CGFloat )score;

@end

#import "Student.h"

@implementation Student

- (instancetype)initWithName:(NSString *)name Gender:(NSString *)gender Number:(NSInteger )number Age:(NSInteger
)age Score:(CGFloat )score

{

self = [super
init];//self继承父类super初始化

if (self) {//如果继承完成以下

self.name = name;

self.gender = gender;

self.number = number;

self.age = age;

self.score = score;

}

return
self;

}

+ (instancetype)studentWithName:(NSString *)name Gender:(NSString *)gender Number:(NSInteger )number Age:(NSInteger
)age Score:(CGFloat )score

{

Student *s = [[Student
alloc] initWithName:name
Gender:gender Number:number
Age:age Score:score];

return s;

}

@end