反射类型

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;
}