iOS 反射

由于ObjC动态性，在ObjC中实现反射可以说是相当简单，下面代码中演示了常用的反射操作，具体作用也都在代码中进行了注释说明:

 

Account.h

//

//  Account.h

//  FoundationFramework

//

//  Created by Kenshin Cui on 14-2-16.

//  Copyright (c) 2014年 Kenshin＋ Cui. All rights reserved.

//

 

#import <Foundation/Foundation.h>

 

@interface Account : NSObject

 

@property (nonatomic,assign) double balance;

 

@end

 

Account.m

//

//  Account.m

//  FoundationFramework

//

//  Created by Kenshin Cui on 14-2-16.

//  Copyright (c) 2014年 Kenshin Cui. All rights reserved.

//

 

#import "Account.h"

 

@implementation Account

 

@end

 

Person.h

 

//  Person.h

//  FoundationFramework

//

//  Created by Kenshin Cui on 14-2-16.

//  Copyright (c) 2014年 Kenshin Cui. All rights reserved.

//

 

#import <Foundation/Foundation.h>

@class Account;

 

@interface Person : NSObject

 

@property (nonatomic,copy) NSString *name;

@property (nonatomic,retain) Account *account;

 

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

 

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

 

-(void)showMessage:(NSString *)infomation;

 

//自己实现对象比较方法

-(NSComparisonResult)comparePerson:(Person *)person;

@end

 

Person.m

//

//  Person.m

//  FoundationFramework

//

//  Created by Kenshin Cui on 14-2-16.

//  Copyright (c) 2014年 Kenshin Cui. All rights reserved.

//

 

#import "Person.h"

 

@implementation Person

 

-(Person *)initWithName:(NSString *)name{

    if(self=[super init]){

        self.name=name;

    }

    return self;

}

 

+(Person *)personWithName:(NSString *)name{

    Person *person=[[Person alloc]initWithName:name];

    return person;

}

 

-(void)showMessage:(NSString *)infomation{

    NSLog(@"My name is %@,the infomation is \"%@\".",_name,infomation);

}

 

//自己实现对象比较方法

-(NSComparisonResult)comparePerson:(Person *)person{

    return [_name compare:person.name];

}

 

-(NSString *)description{

    return [NSString stringWithFormat:@"name=%@",_name];

}

 

@end

 

main.m

//

//  main.m

//  FoundationFramework

//

//  Created by Kenshin Cui on 14-2-16.

//  Copyright (c) 2014年 Kenshin Cui. All rights reserved.

//

 

#import <Foundation/Foundation.h>

#import "Person.h"

 

 

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

    /*常用方法*/

    Person *person1=[Person personWithName:@"Kenshin"];

    NSLog(@"%i",[person1 isKindOfClass:[NSObject class]]); //判断一个对象是否为某种类型（如果是父类也返回YES），结果：1

    NSLog(@"%i",[person1 isMemberOfClass:[NSObject class]]); //判断一个对象是否是某个类的实例化对象，结果：0

    NSLog(@"%i",[person1 isMemberOfClass:[Person class]]); //结果：1

    NSLog(@"%i",[person1 conformsToProtocol:@protocol(NSCopying)]);//是否实现了某个协议，结果：0

    NSLog(@"%i",[person1 respondsToSelector:@selector(showMessage:)]);//是否存在某个方法，结果：1

    

    [person1 showMessage:@"Hello,world!"];//直接调用一个方法

    [person1 performSelector:@selector(showMessage:) withObject:@"Hello,world!"];

    //动态调用一个方法，注意如果有参数那么参数类型只能为ObjC对象，并且最多只能有两个参数

 

    

    /*反射*/

    //动态生成一个类

    NSString *className=@"Person";

    Class myClass=NSClassFromString(className);//根据类名生成类

    Person *person2=[[myClass alloc]init]; //实例化

    person2.name=@"Kaoru";

    NSLog(@"%@",person2);//结果：name=Kaoru

 

    //类转化为字符串

    NSLog(@"%@,%@",NSStringFromClass(myClass),NSStringFromClass([Person class])); //结果：Person,Person

 

    //调用方法

    NSString *methodName=@"showMessage:";

    SEL mySelector=NSSelectorFromString(methodName);

    Person *person3=[[myClass alloc]init];

    person3.name=@"Rosa";

    [person3 performSelector:mySelector withObject:@"Hello,world!"]; //结果：My name is Rosa,the infomation is "Hello,world!".

 

    //方法转化为字符串

    NSLog(@"%@",NSStringFromSelector(mySelector)); //结果：showMessage:

    

    return 0;

}