iOS KVC 简介

//作用-：利用kvc 赋值 （key value coding）键值编码

void test(){

? ? Person *person = [[Person alloc]init];

? ? [person setValue:@"王五" forKey:@"name"];

? ? [person setValue:@"19" forKey:@"money"];

? ? NSLog(@"---%@ ---- %.2f",person.name,person.money);

}

?

//作用二：修改类的私有成员变量（UIpageControl）

void test2(){

? ? Person *person = [[Person alloc]init];

? ? [person printAge];

? ? [person setValue:@"88" forKeyPath:@"_age"];

? ? [person printAge];

}

//作用三：字典转模型

void test3(){

? ? NSDictionary *dict = @{@"name":@"小黄",@"money":@190.88};

? ? Person *person = [Person personWithDict:dict];

? ? NSLog(@"%@",person);

}

//作用四：利用kvc取值

void test4(){

? ? Person *person = [[Person alloc]init];

? ? person.name = @"你好";

? ? NSString *name = [person valueForKey:@"name"];

? ? NSLog(@"%@",name);

}

//作用五：(模型转字典)

void test5(){

? ? Person *person = [[Person alloc]init];

? ? person.name = @"你好";

? ? person.money = 32.32;

? ? NSDictionary * dict = [person dictionaryWithValuesForKeys:@[@"name",@"money"]];

? ? NSLog(@"%@",dict);

}

//作用六： 取出所有模型中的某个属性

void test6(){

? ? //? ? ? ? 取出所有模型中的某个属性

? ? Person *person1 = [[Person alloc]init];

? ? person1.name = @"你好";

? ? person1.money = 92.32;

?? ?

? ? Person *person2 = [[Person alloc]init];

? ? person2.name = @"lisi";

? ? person2.money = 82.32;

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

? ? person3.name = @"wangwu";

? ? person3.money = 892.32;

? ? NSArray *allPersons = @[person1,person2,person3];

? ? NSArray *allPesonName = [allPersons valueForKeyPath:@"name"];

? ? NSLog(@"%@",allPesonName);

}

//模型

#import <Foundation/Foundation.h>

#import "Dog.h"

NS_ASSUME_NONNULL_BEGIN

?

@interface Person : NSObject

//{

//? ? int _age;//ios9之前默认私有变量

//}

?

@property (nonatomic, weak) NSString *name;

@property (nonatomic, weak) NSString *_id;

@property (nonatomic, weak) NSString *descriptionCus;

@property (nonatomic, strong) Dog *dog;

@property (nonatomic, assign) float money;

-(void)printAge;

-(instancetype)initWithDict:(NSDictionary *)dict;

+(instancetype)personWithDict:(NSDictionary *)dict;

@end

?

#import "Person.h"

@implementation Person

{

? ? int _age;//ios9之后放这里，默认私有变量

}

- (instancetype)init

{

? ? self = [super init];

? ? if (self) {

? ? ? ? _age = 8;

? ? }

? ? return self;

}

-(void)printAge{

? ? NSLog(@"==age== %d===",_age);

}

-(NSString *)description{

? ? return [NSString stringWithFormat:@"===%@===%.2f",self.name,self.money];

}

-(instancetype)initWithDict:(NSDictionary *)dict{

? ? if (self = [super init]) {

? ? ? ? [self setValuesForKeysWithDictionary:dict];

//? ? ? ? self.name = dict[@"name"];

//? ? ? ? self.money = [dict[@"money"] floatValue];

? ? }

? ? return self;

}

+(instancetype)personWithDict:(NSDictionary *)dict{

? ? return [[self alloc]initWithDict:dict];

}

//防止后台返回开发中的关键字

-(void)setValue:(id)value forKey:(NSString *)key{

? ? if ([key isEqualToString:@"id"]) {

? ? ? ? self._id = value;

? ? }else if ([key isEqualToString:@"description"]){

? ? ? ? self.descriptionCus = value;

? ? }

}

//找不到key，此方法防止崩溃，赋值空

-(void)setNilValueForKey:(NSString *)key{

? ? [self setValue:@"" forKey:key];

}