Model--Mantle

相比 MJExtension,Mantle 的使用还是有些烦琐，并且效率也并不占优势，但仍有很多可取之处。
最近抽空看了一下简单记录。

• 基础数据

    
    NSDictionary *dic =   @{
                             @"name": @"Bob",
                             @"cars":@[@{@"make":@"ford",
                                          @"year":@"1972" },
                                        @{@"make":@"mazda",
                                          @"year":@"2000" }],

                            @"owner":@{ @"name":@"arthur",
                                        @"gender":@"male",
                                        @"age":@101,
                                        @"date":@"2018-09-02"
                                       },
                             @"url":@"http://www.baidu.com",
                             @"date":@"2015-09-02",
                             };

• 字典转模型

//MTLJSONAdapter 适配器负责转换
    TestModel *model = [MTLJSONAdapter modelOfClass:[TestModel class]
                                 fromJSONDictionary:dic
                                              error:nil];
    
    NSLog(@"%@",model.name);
    NSLog(@"%@",model.date);
    NSLog(@"%@",model.url);
    NSLog(@"%@",model.ownerName);
    
    NSLog(@"%@",model.owner.name);
    NSLog(@"%@",model.owner.gender);
    NSLog(@"%@",model.owner.age);
    NSLog(@"%@",model.owner.date);
    
    CarModel *car1 = model.cars[0];
    CarModel *car2 = model.cars[1];
    NSLog(@"%@",car1.make);
    NSLog(@"%@",car2.year);
    
    NSLog(@"%@",model.maker);

• 模型创建

//model 必须继承自 MTLModel 
//并且遵守 MTLJSONSerializing 协议
@interface TestModel : MTLModel
@property (nonatomic,retain) NSString * name;
@property (nonatomic,retain) NSDate   * date;
@property (nonatomic,retain) NSURL    * url;
@property (nonatomic, copy ) NSString * ownerName;
@property (nonatomic,retain) OwnerModel * owner;
@property (nonatomic,retain) NSArray    * cars;
@property (nonatomic, copy)  NSString    * maker;
@end

• 方法实现

+(NSDictionary*)JSONKeyPathsByPropertyKey{
    return
    // key为 Model 属性,value 为对应 Json 的值
    // 即使字段名一到处也不可省略，不可省略，不可省略。
    @{
      @"name":@"name",
      @"date":@"date",
      @"url":@"url",
      @"ownerName":@"owner.name",
      @"owner":@"owner",
      @"cars":@"cars",
      @"maker":@"cars"
      
      };
    
}
//类型不一致则需要转变值的类型
+(NSValueTransformer *)JSONTransformerForKey:(NSString *)key{
    //NSString-->NSDate
    if ([key isEqualToString:@"date"]) {
        return
        [MTLValueTransformer transformerUsingForwardBlock:^id(NSString *string, BOOL *success, NSError *__autoreleasing *error) {
            //NSString-->NSDate
            return [self.dateFormatter dateFromString:string];
        }];
        
    //NSString --> NSURL    
    }else if([key isEqualToString:@"url"]){
        return [MTLValueTransformer transformerUsingForwardBlock:^id(NSString * urlStr , BOOL *success, NSError *__autoreleasing *error) {
            NSURL *url = [NSURL URLWithString:urlStr];
            return url;
        }];
    //指向字典
    }else if([key isEqualToString:@"owner"]){
        
        return [MTLJSONAdapter dictionaryTransformerWithModelClass:[OwnerModel class]];
        //或者
        return [MTLValueTransformer transformerUsingForwardBlock:^id(NSDictionary* dic, BOOL *success, NSError *__autoreleasing *error) {
  
            return [MTLJSONAdapter modelOfClass:[OwnerModel class] fromJSONDictionary:dic error:nil];
                  }];
     //指向数组
    }else if([key isEqualToString:@"cars"]){
        
        return [MTLJSONAdapter arrayTransformerWithModelClass:[CarModel class]];
      //指向数组中的某个值
    }else if([key isEqualToString:@"maker"]){
        
       return  [MTLValueTransformer transformerUsingForwardBlock:^id(NSArray * cars , BOOL *success, NSError *__autoreleasing *error) {
            return [cars.firstObject
                    valueForKey:@"make"];
        }];
    }else{
       return nil;
    }
}

+ (NSDateFormatter *)dateFormatter {
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    dateFormatter.dateFormat = @"yyyy-MM-dd";
    return dateFormatter;
}
@end