iOS -- KVC && KVO

#import "ViewController.h"
#import "Person.h"
#import "Student.h"
@interface ViewController ()
{
    NSString *_text;
}
@property (weak, nonatomic) IBOutlet UITextField *plicceholder;
@property (nonatomic, strong) Person *person;
@property (nonatomic, strong) NSMutableArray *tempArray;
@end

@implementation ViewController
//KVC key -Value - Coding

//KVO ,key - value - observer,键值观察,属性只要调用set方法就会触发KCO
- (void)viewDidLoad {
    [super viewDidLoad];
  
    [self.plicceholder setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];
    //属性初始化,必须使用self.进行调用.
    self.person = [[Person alloc] init];
    //1.添加观察者
    //2.self.person是被观察的对象本身
    //self,观察者
    //keyPath,观察的实例变量
    //options ,观察哪方面
    [self.person addObserver:self forKeyPath:@"name" options:NSKeyValueObservingOptionNew context:nil];
    
    
    [self.person addObserver:self forKeyPath:@"_age" options:NSKeyValueObservingOptionNew context:nil];
    
    [self addObserver:self forKeyPath:@"_text" options:NSKeyValueObservingOptionNew context:nil];
    
    
    self.tempArray = [@[] mutableCopy];
    [self addObserver:self forKeyPath:@"tempArray" options:NSKeyValueObservingOptionNew context:nil];
}

- (IBAction)kvo_fire:(id)sender {
    
    //self.person.name = @"张浩浩";
    [self.person setValue:@"18" forKey:@"_age"];
    
    
}



//接收kvo触发事件
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context{
    NSLog(@"object = %@,keyPath = %@", object,keyPath);
   // NSLog(@"%@", keyPath);
}
- (IBAction)kvc_setValueForKey:(id)sender {
    
    Person *p = [[Person alloc] init];
    
    [p setValue:@"豪豪" forKey:@"name"];
    NSLog(@"%@", p.name);
    
    [p setValue:@"18" forKey:@"_age"];
    NSLog(@"%@",[p valueForKey:@"_age"]);
}
- (IBAction)kvc_setValueForPath:(id)sender {
    Student *stu =[[Student alloc] init];
//    Person *p = [[Person alloc] init];
//    stu.per = p;
    [stu setValue:@"豪豪" forKeyPath:@"per.age"];
    NSLog(@"%@", [stu valueForKeyPath:@"per.age"]);
    
}




- (IBAction)kvc_setValuserForkeysWithDictionary:(id)sender {
    
    NSDictionary *dic = @{@"name":@"张豪豪",@"gender":@"男"};
    Person *p = [[Person alloc] init];
    
    [p setValuesForKeysWithDictionary:dic];
    
    NSLog(@"%@", p.name);
    
    
}
- (IBAction)kvc_sum:(id)sender {
    
    NSMutableArray *ary = [@[] mutableCopy];
    for (int i = 0; i < 100; i++) {
        [ary addObject:[NSString stringWithFormat:@"%d", i]];
    }
    NSLog(@"%@", [ary valueForKeyPath:@"@sum.integerValue"]); 
}

- (IBAction)kvo_observerself:(id)sender {
    
    [self setValue:@"biubiu" forKey:@"_text"];
    
}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
- (void)dealloc{
    
    //观察着不需要的时候,就需要进行注销,并不是绝对的在dealloc里面
    [self.person removeObserver:self forKeyPath:@"name"];
    [self.person removeObserver:self forKeyPath:@"_age"];
    [self removeObserver:self forKeyPath:@"_text"];
}
- (IBAction)kvo_mutableArray:(id)sender {
    //kvo 观察数组
    [[self mutableArrayValueForKey:@"tempArray"] addObject:@"zhaoahao"];
    
}




@end

Person.h

#import <Foundation/Foundation.h>

@interface Person : NSObject
{
    NSString *_age;
}
@property (nonatomic, copy) NSString *name;

@end

person.m

#import "Person.h"

@implementation Person
//属性关联实例变量
@synthesize name = _name;
- (void)setValue:(id)value forUndefinedKey:(NSString *)key{
    
}


@end

student.h

#import <Foundation/Foundation.h>
@class Person;
@interface Student : NSObject
@property (nonatomic, strong) Person *per;
@end

student.m

#import "Student.h"
#import "Person.h"
@implementation Student
- (id)init{
    self = [super init];
    if (self) {
        self.per = [[Person alloc] init];
    }
    return self;
}
@end