我在我的目标c应用程序中有一个使用JSONModel的模型。 JSONModel github我正在尝试从服务器的响应初始化我的模型。服务器的响应是这样的:
[ { “ id”:0, “名称”:“ Jhon” }, { “ id”:1 “名称”:“迈克” }, { “ id”:2 “名称”:“卢阿” }]
我的JSONModel是:
@protocol People @end
@interface People : JSONModel
@property (nonatomic, strong) NSArray <Person> * peopleArray;
@end
@protocol Person @end
@interface Person : JSONModel
@property (nonatomic, strong) NSNumber <Optional> * id;
@property (nonatomic, strong) NSString <Optional> * name;
@end
我正在尝试初始化它,然后从服务器获取响应:
NSError *error;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:responseData options:NSJSONWritingPrettyPrinted error:&error];
People *peoplemodel = [[People alloc] initWithData:jsonData error:&error];
但是我得到一个空模型。
我认为问题在于格式响应
[{}]
但是我不知道该如何转换。
是否可以从json对象数组中初始化JSONModel?
我该怎么做?
答案 0 :(得分:0)
您引用的库似乎仅与NSDictionary根Json对象兼容,而您具有NSArray根json对象。
https://github.com/jsonmodel/jsonmodel/blob/master/JSONModel/JSONModel/JSONModel.m#L123
https://github.com/jsonmodel/jsonmodel/blob/master/JSONModel/JSONModel/JSONModel.m#L161
如果您检查尝试初始化initWithData时返回的错误,我确定它将显示以下错误消息:
无效的JSON数据:尝试使用initWithDictionary:error初始化JSONModel对象,但dictionary参数不是'NSDictionary'。
您当前的服务器JSON响应:
NSArray <NSDictionary *> *jsonArray = @[ @{ @"id": @(0), @"name": @"Jhon" }, @{ @"id": @(1), @"name": @"Mike" }, @{ @"id": @(2), @"name": @"Lua" } ];
有关JSONModel库能够解析的JSON的示例:
NSDictionary <NSString *, NSArray <NSDictionary *> *> *jsonDictionary = @{ @"peopleArray": @[@{@"id": @(0), @"name": @"Jhon"}, @{ @"id": @(1), @"name": @"Mike" }, @{ @"id": @(2), @"name": @"Lua" }]};
如果您无法在后端上修改服务器响应以使其返回NSDictionary作为根JSON对象,则可以对返回的数据进行预处理,以格式化为JSONModel lib期望的格式(NSDictionary根)。 / p>
这是我的意思的示例(具体地说,您将希望使用jsonDataUsingYourCurrentArrayStructureWithPreProcessing:
之类的东西来预处理JSON数据:
- (void)viewDidLoad {
[super viewDidLoad];
NSArray <NSDictionary *> *jsonArray = @[ @{ @"id": @(0), @"name": @"Jhon" }, @{ @"id": @(1), @"name": @"Mike" }, @{ @"id": @(2), @"name": @"Lua" } ];
NSError *jsonSerializationError;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:jsonArray options:0 error:&jsonSerializationError];
if (jsonSerializationError) {
NSLog(@"jsonSerializationError = %@", jsonSerializationError);
}
jsonData = [self jsonDataUsingYourCurrentArrayStructureWithPreProcessing:jsonData];
NSError *jsonModelError;
People *people = [[People alloc] initWithData:jsonData error:&jsonModelError];
if (people) {
[self printPeople:people];
} else if (jsonModelError != nil) {
NSLog(@"Error returned from jsonModel = %@", jsonModelError);
}
}
- (void)printPeople:(People *)people {
for (Person *person in people.peopleArray) {
NSLog(@"person id = %li, name = %@", [person.id integerValue], person.name);
}
}
- (NSData *)jsonDataUsingYourCurrentArrayStructureWithPreProcessing:(NSData *)jsonData {
NSError *parsingError;
id obj = [NSJSONSerialization JSONObjectWithData:jsonData
options:0
error:&parsingError];
if ([obj isKindOfClass:[NSArray class]] && parsingError == nil) {
NSArray <NSDictionary *> *jsonArray = (NSArray <NSDictionary *> *)obj;
NSDictionary *jsonDictionary = [NSDictionary dictionaryWithObject:jsonArray forKey:@"peopleArray"];
NSError *jsonSerializationError;
NSData *jsonDictData = [NSJSONSerialization dataWithJSONObject:jsonDictionary options:0 error:&jsonSerializationError];
if (jsonDictData && jsonSerializationError == nil) {
return jsonDictData;
} else {
NSLog(@"jsonSerializationError = %@", jsonSerializationError);
return nil;
}
} else {
if (parsingError) {
NSLog(@"Error parsing jsonData = %@", parsingError);
}
return nil;
}
}
或者,您可以从JSON数组中进行自己的初始化,在People类中遵循以下几行:
+ (instancetype)peopleWithJsonArray:(NSArray<NSDictionary *> *)jsonArray {
People *people = [[People alloc] init];
if (people) {
[people setupPeopleArrayFromJsonArray:jsonArray];
}
return people;
}
- (void)setupPeopleArrayFromJsonArray:(NSArray <NSDictionary *> *)jsonArray {
NSMutableArray <Person *> *people = [[NSMutableArray alloc] initWithCapacity:jsonArray.count];
for (NSDictionary *personDictionary in jsonArray) {
Person *person = [Person personWithID:[personDictionary objectForKey:@"id"] andName:[personDictionary objectForKey:@"name"]];
[people addObject:person];
}
self.peopleArray = [NSArray arrayWithArray:people];
}