YYModel Effect-> YYModel的作用
Provide some data-model method—>提供一些數據模型的方法
Convert json to any object, or convert any object to json.->對任何對象轉換成JSON，和對任何JSON轉換為對象
Set object properties with a key-value dictionary (like KVC).設置一個屬性與鍵值對字典(如KVC)
KVC -> key - value - coding(鍵值編碼)
Implementations of `NSCoding`, `NSCopying`, `-hash` and `-isEqual:`.->對鍵值編碼、拷貝、哈希、和一樣的
See `YYModel` protocol for custom methods.看到YYModel自定義的方法
Sample Code -> 舉例子
********************** json convertor ********************* ?JSON轉模型對象
@interface YYAuthor : NSObject -> 作者類
@property (nonatomic, strong) NSString *name; ?名字
???? @property (nonatomic, assign) NSDate *birthday; 生日
???? @end
???? @implementation YYAuthor ??
???? @end
???? @property (nonatomic, assign) NSDate *birthday; 生日
???? @end
???? @implementation YYAuthor ??
???? @end
@interface YYBook : NSObject ?-> 書本類
@property (nonatomic, copy) NSString *name; ?書本名字
@property (nonatomic, assign) NSUInteger pages; 書本頁數?
@property (nonatomic, strong) YYAuthor *author; 書本的作者
@end
???? @implementation YYBook
???? @end
???
???? @implementation YYBook
???? @end
???
int main()?{
// create model from json -> 從JSON字符串創建模型
YYAuthor *author = [YYAuthor yy_modelWithJSON:@“{\”name\”:\”Jack\”},\“brithday\”:\”1994-10-22\"}”];
YYBook *book = [YYBook yy_modelWithJSON:@"{\"name\": \"Harry Potter\", \"pages\": 256, \"author\": {\"name\": \"J.K.Rowling\", \"birthday\": \"1965-07-31\" }}"];
?
?
// convert model to json
NSString *json = [book yy_modelToJSONString]; 從模型轉JSON字符串
// {"author":{"name":"J.K.Rowling","birthday":"1965-07-31T00:00:00+0000"},"name":"Harry Potter","pages":256}
}
frist?method
+ (nullable instancetype)yy_modelWithJSON:(id)json; ?外界傳一個JSON給我我返回一個模型給他
?
?
YYModel的方法
/**
Creates and returns a new instance of the receiver from a json.創建和返回一個JSON從接收器中的一個新實例
This method is thread-safe. 這個方法是線程安全的
@param json? A json object in `NSDictionary`, `NSString` or `NSData`.字典參數（JSON對象、字符串、和數據)
@return A new instance created from the json, or nil if an error occurs.返回一個新的JSON格式的實例對象或者如果出現錯誤零
*/
+ (nullable instancetype)yy_modelWithJSON:(id)json; ?外界傳一個JSON給我我返回一個模型給他
實現：
+ (instancetype)yy_modelWithJSON:(id)json {
NSDictionary *dic = [self _yy_dictionaryWithJSON:json];// 這里就把JSON轉化為字典
return [self yy_modelWithDictionary:dic];
}
// 外界傳字典進來返回一個模型
+ (instancetype)yy_modelWithDictionary:(NSDictionary *)dictionary {
??? if (!dictionary || dictionary == (id)kCFNull) return nil;
??? if (![dictionary isKindOfClass:[NSDictionary class]]) return nil;
???
??? if (!dictionary || dictionary == (id)kCFNull) return nil;
??? if (![dictionary isKindOfClass:[NSDictionary class]]) return nil;
???
Class cls = [self class];
// ?Returns the cached model class meta返回存儲模型類元
_YYModelMeta *modelMeta = [_YYModelMeta metaWithClass:cls];
if (modelMeta->_hasCustomClassFromDictionary) {// 自定義類字典
->返回類創建從這字典，使用這個類
cls = [cls modelCustomClassForDictionary:dictionary] ?: cls;
??? }
???
??? NSObject *one = [cls new];
??? if ([one yy_modelSetWithDictionary:dictionary]) return one;
??? return nil;
??? }
???
??? NSObject *one = [cls new];
??? if ([one yy_modelSetWithDictionary:dictionary]) return one;
??? return nil;
}
// 這里是把JSON轉化為字典的實現方法
+ (NSDictionary *)_yy_dictionaryWithJSON:(id)json {// 字典WithJSON
if (!json || json == (id)kCFNull) return nil;// 如果JSON為空直接return
NSDictionary *dic = nil;// 創建一個空的字典
NSData *jsonData = nil;// 創建一個空的數據
// ?因為就只有三種格式可以轉換為字典模型的(JSON、字符串、數據)
if ([json isKindOfClass:[NSDictionary class]]) {
dic = json;
} else if ([json isKindOfClass:[NSString class]]) {// 如果數據類型為字符串的話，還要進行一個NSData轉換
jsonData = [(NSString *)json dataUsingEncoding : NSUTF8StringEncoding];
??? } else if ([json isKindOfClass:[NSData class]]) {
??????? jsonData = json;
??? }
??? if (jsonData) {
??????? dic = [NSJSONSerialization JSONObjectWithData:jsonData options:kNilOptions error:NULL];
??????? if (![dic isKindOfClass:[NSDictionary class]]) dic = nil;
??? }
??? return dic;
??? } else if ([json isKindOfClass:[NSData class]]) {
??????? jsonData = json;
??? }
??? if (jsonData) {
??????? dic = [NSJSONSerialization JSONObjectWithData:jsonData options:kNilOptions error:NULL];
??????? if (![dic isKindOfClass:[NSDictionary class]]) dic = nil;
??? }
??? return dic;
}
/**
If you need to create instances of different classes during json->object transform, ->如果你需要創建實例類在JSON->對象變換
use the method to choose custom class based on dictionary data.-> 利用字典數據選擇自定義類的方法
@discussion If the model implements this method, ->如果這個模型實現咯這個方法
it will be called to determine resulting class -> 它將被調用產生的類
during `+modelWithJSON:`, `+modelWithDictionary:`, ->在轉換的期間里JSON轉換模型或自定啊轉換模型
conveting object of properties of parent objects -> 轉換對父對象的屬性對象
(both singular and containers via `+modelContainerPropertyGenericClass`). ->容器通過
?Example:例子
??????? @class YYCircle, YYRectangle, YYLine;
?
??????? @implementation YYShape
// 這樣判斷更為嚴謹
+ (Class)modelCustomClassForDictionary:(NSDictionary*)dictionary {
if (dictionary[@"radius"] != nil) {// 如果半徑不為空
return [YYCircle class];// 返回一個圈
} else if (dictionary[@"width"] != nil) { // 如果寬度不為空
return [YYRectangle class]; // 返回一個矩形
} else if (dictionary[@"y2"] != nil) { // 如果Y值不為空
return [YYLine class]; // 那么返回一跳線
} else {
return [self class]; // 如果都不滿足返回自己這個類
}
??????? }
??????? @end
?@param dictionary The json/kv dictionary.
??????? }
??????? @end
?@param dictionary The json/kv dictionary.
@return Class to create from this dictionary, `nil` to use current class. ->返回類創建從這字典，使用這個類
*/
cls = [cls modelCustomClassForDictionary:dictionary] ?: cls;
?
