在项目中模型是必不可少的, 那么字典转换模型就显得格外重要. 字典转模型我使用的是MJExtension, 想必大家都不陌生这个框架, 下面我们来了解一下这个框架怎么使用.
安装
// 使用cocoaPods
pod 'MJExtension'
示例使用
1.最简单的字典转模型
typedef enum {
SexMale,
SexFemale
} Sex;
@interface User : NSObject
@property (copy, nonatomic) NSString *name;
@property (copy, nonatomic) NSString *icon;
@property (assign, nonatomic) unsigned int age;
@property (copy, nonatomic) NSString *height;
@property (strong, nonatomic) NSNumber *money;
@property (assign, nonatomic) Sex sex;
@property (assign, nonatomic, getter=isGay) BOOL gay;
@end
/***********************************************/
// 构造字典
NSDictionary *dict = @{
@"name" : @"Jack",
@"icon" : @"lufy.png",
@"age" : @20,
@"height" : @"1.55",
@"money" : @100.9,
@"sex" : @(SexFemale),
@"gay" : @"true"
};
// 字典转模型
User *user = [User mj_objectWithKeyValues:dict];
NSLog(@"name=%@, icon=%@, age=%zd, height=%@, money=%@, sex=%d, gay=%d", user.name, user.icon, user.age, user.height, user.money, user.sex, user.gay);
// name=Jack, icon=lufy.png, age=20, height=1.550000, money=100.9, sex=1
2.JSON字符串转模型
// 1.Define a JSONString
NSString *jsonString = @"{\"name\":\"Jack\", \"icon\":\"lufy.png\", \"age\":20}";
// 2.JSONString -> User
User *user = [User mj_objectWithKeyValues:jsonString];
// 3.Print user's properties
NSLog(@"name=%@, icon=%@, age=%d", user.name, user.icon, user.age);
// name=Jack, icon=lufy.png, age=20
3.模型中嵌套模型!!!(重点)
@interface Status : NSObject
@property (copy, nonatomic) NSString *text;
@property (strong, nonatomic) User *user;
@property (strong, nonatomic) Status *retweetedStatus;
@end
/***********************************************/
// 构造字典
NSDictionary *dict = @{
@"text" : @"Agree!Nice weather!",
@"user" : @{
@"name" : @"Jack",
@"icon" : @"lufy.png"
},
@"retweetedStatus" : @{
@"text" : @"Nice weather!",
@"user" : @{
@"name" : @"Rose",
@"icon" : @"nami.png"
}
}
};
// 字典转模型
Status *status = [Status mj_objectWithKeyValues:dict];
NSString *text = status.text;
NSString *name = status.user.name;
NSString *icon = status.user.icon;
NSLog(@"text=%@, name=%@, icon=%@", text, name, icon);
// text=Agree!Nice weather!, name=Jack, icon=lufy.png
NSString *text2 = status.retweetedStatus.text;
NSString *name2 = status.retweetedStatus.user.name;
NSString *icon2 = status.retweetedStatus.user.icon;
NSLog(@"text2=%@, name2=%@, icon2=%@", text2, name2, icon2);
// text2=Nice weather!, name2=Rose, icon2=nami.png
4.模型中有个数组属性，数组里面又要装着其他模型!!!(重点)
@interface Ad : NSObject
@property (copy, nonatomic) NSString *image;
@property (copy, nonatomic) NSString *url;
@end
@interface StatusResult : NSObject
/** Contatins status model */
@property (strong, nonatomic) NSMutableArray *statuses;
/** Contatins ad model */
@property (strong, nonatomic) NSArray *ads;
@property (strong, nonatomic) NSNumber *totalNumber;
@end
/***********************************************/
// 在.m文件里面添加
+ (NSDictionary *)mj_objectClassInArray {
return @{
@"statuses" : @"Status",
@"ads" : @"Ad"
};
}
NSDictionary *dict = @{
@"statuses" : @[
@{
@"text" : @"Nice weather!",
@"user" : @{
@"name" : @"Rose",
@"icon" : @"nami.png"
}
},
@{
@"text" : @"Go camping tomorrow!",
@"user" : @{
@"name" : @"Jack",
@"icon" : @"lufy.png"
}
}
],
@"ads" : @[
@{
@"image" : @"ad01.png",
@"url" : @"http://www.ad01.com"
},
@{
@"image" : @"ad02.png",
@"url" : @"http://www.ad02.com"
}
],
@"totalNumber" : @"2014"
};
// JSON -> StatusResult
StatusResult *result = [StatusResult mj_objectWithKeyValues:dict];
NSLog(@"totalNumber=%@", result.totalNumber);
// totalNumber=2014
// Printing
for (Status *status in result.statuses) {
NSString *text = status.text;
NSString *name = status.user.name;
NSString *icon = status.user.icon;
NSLog(@"text=%@, name=%@, icon=%@", text, name, icon);
}
// text=Nice weather!, name=Rose, icon=nami.png
// text=Go camping tomorrow!, name=Jack, icon=lufy.png
// Printing
for (Ad *ad in result.ads) {
NSLog(@"image=%@, url=%@", ad.image, ad.url);
}
// image=ad01.png, url=http://www.ad01.com
// image=ad02.png, url=http://www.ad02.com
5.模型中的属性名和字典中的key不相同(或者需要多级映射)!!!(重点)
@interface Bag : NSObject
@property (copy, nonatomic) NSString *name;
@property (assign, nonatomic) double price;
@end
@interface Student : NSObject
@property (copy, nonatomic) NSString *ID;
@property (copy, nonatomic) NSString *desc;
@property (copy, nonatomic) NSString *nowName;
@property (copy, nonatomic) NSString *oldName;
@property (copy, nonatomic) NSString *nameChangedTime;
@property (strong, nonatomic) Bag *bag;
@end
/***********************************************/
// 在.m文件里面添加
+ (NSDictionary *)mj_replacedKeyFromPropertyName {
return @{@"ID" : @"id",
@"desc" : @"description",
@"oldName" : @"name.oldName",
@"nowName" : @"name.newName",
@"nameChangedTime" : @"name.info[1].nameChangedTime",
@"bag" : @"other.bag"};
}
NSDictionary *dict = @{
@"id" : @"20",
@"description" : @"kids",
@"name" : @{
@"newName" : @"lufy",
@"oldName" : @"kitty",
@"info" : @[
@"test-data",
@{
@"nameChangedTime" : @"2013-08"
}
]
},
@"other" : @{
@"bag" : @{
@"name" : @"a red bag",
@"price" : @100.7
}
}
};
// JSON -> Student
Student *stu = [Student mj_objectWithKeyValues:dict];
// Printing
NSLog(@"ID=%@, desc=%@, oldName=%@, nowName=%@, nameChangedTime=%@",
stu.ID, stu.desc, stu.oldName, stu.nowName, stu.nameChangedTime);
// ID=20, desc=kids, oldName=kitty, nowName=lufy, nameChangedTime=2013-08
NSLog(@"bagName=%@, bagPrice=%f", stu.bag.name, stu.bag.price);
// bagName=a red bag, bagPrice=100.700000
6.将一个字典数组转成模型数组!!!(重点)
NSArray *dictArray = @[
@{
@"name" : @"Jack",
@"icon" : @"lufy.png"
},
@{
@"name" : @"Rose",
@"icon" : @"nami.png"
}
];
// JSON array -> User array
NSArray *userArray = [User mj_objectArrayWithKeyValuesArray:dictArray];
// Printing
for (User *user in userArray) {
NSLog(@"name=%@, icon=%@", user.name, user.icon);
}
// name=Jack, icon=lufy.png
// name=Rose, icon=nami.png
7.将一个模型转成字典
// New model
User *user = [[User alloc] init];
user.name = @"Jack";
user.icon = @"lufy.png";
Status *status = [[Status alloc] init];
status.user = user;
status.text = @"Nice mood!";
// Status -> JSON
NSDictionary *statusDict = status.mj_keyValues;
NSLog(@"%@", statusDict);
/*
{
text = "Nice mood!";
user = {
icon = "lufy.png";
name = Jack;
};
}
*/
// More complex situation
Student *stu = [[Student alloc] init];
stu.ID = @"123";
stu.oldName = @"rose";
stu.nowName = @"jack";
stu.desc = @"handsome";
stu.nameChangedTime = @"2018-09-08";
Bag *bag = [[Bag alloc] init];
bag.name = @"a red bag";
bag.price = 205;
stu.bag = bag;
NSDictionary *stuDict = stu.mj_keyValues;
NSLog(@"%@", stuDict);
/*
{
ID = 123;
bag = {
name = "\U5c0f\U4e66\U5305";
price = 205;
};
desc = handsome;
nameChangedTime = "2018-09-08";
nowName = jack;
oldName = rose;
}
*/
8.将一个模型数组转成字典数组
// New model array
User *user1 = [[User alloc] init];
user1.name = @"Jack";
user1.icon = @"lufy.png";
User *user2 = [[User alloc] init];
user2.name = @"Rose";
user2.icon = @"nami.png";
NSArray *userArray = @[user1, user2];
// Model array -> JSON array
NSArray *dictArray = [User mj_keyValuesArrayWithObjectArray:userArray];
NSLog(@"%@", dictArray);
/*
(
{
icon = "lufy.png";
name = Jack;
},
{
icon = "nami.png";
name = Rose;
}
)
*/
9.Core Data存储
NSDictionary *dict = @{
@"name" : @"Jack",
@"icon" : @"lufy.png",
@"age" : @20,
@"height" : @1.55,
@"money" : @"100.9",
@"sex" : @(SexFemale),
@"gay" : @"true"
};
// This demo just provide simple steps
NSManagedObjectContext *context = nil;
User *user = [User mj_objectWithKeyValues:dict context:context];
[context save:nil];
10.统一转换属性名（比如驼峰转下划线）
// Dog
#import "MJExtension.h"
@implementation Dog
+ (NSString *)mj_replacedKeyFromPropertyName121:(NSString *)propertyName
{
// nickName -> nick_name
return [propertyName mj_underlineFromCamel];
}
@end
// NSDictionary
NSDictionary *dict = @{
@"nick_name" : @"旺财",
@"sale_price" : @"10.5",
@"run_speed" : @"100.9"
};
// NSDictionary -> Dog
Dog *dog = [Dog mj_objectWithKeyValues:dict];
// printing
NSLog(@"nickName=%@, scalePrice=%f runSpeed=%f", dog.nickName, dog.salePrice, dog.runSpeed);
11.NSString -> NSDate, nil -> @""【过滤字典的值（比如字符串日期处理为NSDate、字符串nil处理为@""）】!!!(重点)
// Book
#import "MJExtension.h"
@implementation Book
- (id)mj_newValueFromOldValue:(id)oldValue property:(MJProperty *)property
{
if ([property.name isEqualToString:@"publisher"]) {
if (oldValue == nil) return @"";
} else if (property.type.typeClass == [NSDate class]) {
NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
fmt.dateFormat = @"yyyy-MM-dd";
return [fmt dateFromString:oldValue];
}
return oldValue;
}
@end
// NSDictionary
NSDictionary *dict = @{
@"name" : @"5分钟突破iOS开发",
@"publishedTime" : @"2011-09-10"
};
// NSDictionary -> Book
Book *book = [Book mj_objectWithKeyValues:dict];
// printing
NSLog(@"name=%@, publisher=%@, publishedTime=%@", book.name, book.publisher, book.publishedTime);
12.模型归档!!!(重点)
// 在.m文件里面添加
//对象的归档和反归档
MJExtensionCodingImplementation
13.转换完成
/**
* 当字典转模型完毕时调用
*/
- (void)mj_didConvertToObjectWithKeyValues:(NSDictionary *)keyValues;
/**
* 当模型转字典完毕时调用
*/
- (void)mj_objectDidConvertToKeyValues:(NSDictionary *)keyValues;
14.更多用法
参考 NSObject+MJKeyValue.h and NSObject+MJCoding.h