Objective-C之Foundation框架的NSObject和反射机制的应用

NSObject常用的方法：
所有的OC对象都有这些方法，见demo的代码

反射：
Class的反射
通过类名的字符串形式实例化对象
Class class = NSClassFromString(@"Student");
Student *stu = [[class alloc] init];

类名转换为字符串:
Class class = [Student class];
NSString *className = NSStringFromClass(class);

SEL反射：
通过方法的字符串形式实例化方法
SEL selector = NSSelectorFromString(@"setName:");
[stu performSelector withObject:@"mike"];

方法转变成字符串：
NSStringFromSelector(@selector(setName:));

测试demo代码如下：

#import <Foundation/Foundation.h>
#import "Person.h"
#import "Student.h"

void nsObject(){
    id stu = [[[Student alloc] init] autorelease];
    //isKindOfClass判断对象是否属于某个类或者子类
    if ([stu isKindOfClass:[Person class] ]) {
        NSLog(@"stu属于Person或者继承自Person");
    }
    //isMemberOfClass判断某个对象是否属于某个类（不包含子类）
    BOOL result = [stu isMemberOfClass:[NSObject class]];
    NSLog(@"%i", result);
   
    //直接调用
    [stu tests];
    //间接调用
    [stu performSelector:@selector(tests)];
    [stu performSelector:@selector(test2:) withObject:@"abc"];
   
    //延迟2秒调用
    [stu performSelector:@selector(test2:) withObject:@"123" afterDelay:2];
}

void reflect(){
    //字符串变class
    NSString *str = @"Student";
    Class class = NSClassFromString(str);
   
    Student *stu = [[class alloc] init];
    NSLog(@"%@",stu);
    
    //class 变字符串
    NSString * name = NSStringFromClass([Person class]);
    NSLog(@"name:%@", name);
   
    //方法的反射
    NSString *method = @"tests";
    SEL selector = NSSelectorFromString(method);
    [stu performSelector:selector];
   
    //将SEL转化为字符串
    NSString *selectorName = NSStringFromSelector(selector);
    NSLog(@"%@", selectorName);
   
    [stu release];
   
}

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

    @autoreleasepool {
        NSLog(@"----nsObject----");
        nsObject();
        NSLog(@"----reflect----");
        reflect();
    }
    return 0;
}
Person.h文件：
#import <Foundation/Foundation.h>
@interface Person : NSObject
@end

Person.m文件：
#import "Person.h"
@implementation Person
@end

Student.h文件；

#import "Person.h"
@interface Student : Person
- (void)tests;
- (void)test2:(NSString *) param;
@end

Student.m文件：

#import "Student.h"
@implementation Student
- (void)tests{
    NSLog(@"excute 'test' method");
}
- (void)test2:(NSString *)param{
    NSLog(@"excete 'test2' method and param is %@",param);
}
@end