NSObject方法介绍

NSObject是OC中的基类,所有类都继承于此,这里面也给我们提供了很多与“类”和“方法”相关的方法,本文将讲解几个非常实用的方法。


环境信息
Mac OS X 10.9
xcode 5.1.1

正文:

Person.h


#import <Foundation/Foundation.h>

@interface Person : NSObject
@end

Student.h


#import "Person.h"

// 继承Person类
@interface Student : Person

- (void)test1;
- (void)test2:(NSString *)string;

@end

MyProtocol.h


#import <Foundation/Foundation.h>

@protocol MyProtocol
@end

1. 判断student是否是Person类的对象


// - (BOOL)isMemberOfClass:(Class)aClass;
[student isMemberOfClass:[Person class]];

2. 判断student是否是Person类或子类的对象


// - (BOOL)isKindOfClass:(Class)aClass;
[student isKindOfClass:[Person class]];

3. 判断student是否遵循MyProtocol协议(也可以用类调用,判断该类是否遵循)


// - (BOOL)conformsToProtocol:(Protocol *)aProtocol;
[student conformsToProtocol:@protocol(MyProtocol)];

// 或者使用类方法
// + (BOOL)conformsToProtocol:(Protocol *)protocol;
[Student conformsToProtocol:@protocol(MyProtocol)];

4. 判断student的test1方法是否响应(即:是否声明并实现了test1方法)


// - (BOOL)respondsToSelector:(SEL)aSelector;
[student respondsToSelector:@selector(test1)];

5. 间接调用student的test1方法(test1无参数)


// - (id)performSelector:(SEL)aSelector;
[student performSelector:@selector(test1)];

6. 间接调用student的test2方法(test2有一个参数)


// - (id)performSelector:(SEL)aSelector withObject:(id)object;
[student performSelector:@selector(test2:) withObject:@"123"];

// 最多带两个参数
//- (id)performSelector:(SEL)aSelector withObject:(id)object1 withObject:(id)object2;

7. 延迟2s调用student的test1方法

(在命令行没有延迟效果,因为命令行执行完后就退出main函数了 ,在IOS部分main函数一直在执行,所以可以看到延迟效果)


// - (void)performSelector:(SEL)aSelector withObject:(id)anArgument afterDelay:(NSTimeInterval)delay;
// delay单位为(秒)
[student performSelector:@selector(test2:) withObject:@"123" afterDelay:2];