Restkit：RKValueTransformer transformationBlock不叫

這是我有：Restkit：RKValueTransformer transformationBlock不叫

在我的JSON響應

我有一組選項： Options : ["red","green", "blue"]

我想將其轉換爲字符串：options = @"red, green, blue";（我已經將menuComponent實體的options屬性定義爲'NSString'）

我已經爲該屬性提供了一個customValueTransformer，但不會調用transformationBlock。有沒有人有任何想法我做錯了什麼？

RKEntityMapping *menuComponentMapping = [RKEntityMapping mappingForEntityForName:@"MenuComponent" inManagedObjectStore:managedObjectStore]; 

menuComponentMapping.identificationAttributes = @[@"menuComponentID"]; 
[menuComponentMapping addAttributeMappingsFromDictionary:@{ 
                  @"ID":@"menuComponentID", 
                  @"Name":@"name", 
                  @"Description":@"descriptions", 
                  @"Thumbnail":@"thumbnail" 
                  }]; 
//every menu component have some options 
RKAttributeMapping *optionsMapping = [RKAttributeMapping attributeMappingFromKeyPath:@"Options" toKeyPath:@"options"]; 

//converting options to string 
RKValueTransformer *arrayToStringTransformer = [RKBlockValueTransformer valueTransformerWithValidationBlock:^BOOL(__unsafe_unretained Class sourceClass, __unsafe_unretained Class destinationClass) { 
    // I don't know check what with what! 
    return ([sourceClass isSubclassOfClass:[NSNumber class]] && [destinationClass isSubclassOfClass:[NSString class]]); 
} transformationBlock:^BOOL(id inputValue, __autoreleasing id *outputValue, Class outputValueClass, NSError *__autoreleasing *error) { 
    // Validate the input and output 

    // Perform the transformation 
// iterating through options and append to a string 

    return YES; 
}]; 

//adding custom value transformer 
optionsMapping.valueTransformer = arrayToStringTransformer; 
//adding optionsMapping 
[menuComponentMapping addPropertyMapping:optionsMapping]; 
[[RKValueTransformer defaultValueTransformer] insertValueTransformer:arrayToStringTransformer atIndex:0]; 

RKRelationshipMapping *menuComponentRelationShip = [RKRelationshipMapping relationshipMappingFromKeyPath:@"MenuComponents" toKeyPath:@"children" withMapping:menuComponentMapping]; 

//adding menucomponent children relationship to menuComponent 
[menuComponentMapping addPropertyMapping:menuComponentRelationShip]; 

return menuComponentMapping; 
}

來源

2014-12-27 Hashem Aboonajmi

你的代碼甚至註釋本節作爲一個問題：

// I don't know check what with what! 
return ([sourceClass isSubclassOfClass:[NSNumber class]] && [destinationClass isSubclassOfClass:[NSString class]]);

，因爲你是不是想從NSNumber轉換，你想從一個NSArray轉換。如果類型不匹配，則不會使用變壓器。

如果該塊沒有被調用，那麼問題出在變換器註冊。這應該不會發生變壓器直接提供給映射，但你沒有顯示如何使用映射...

來源

2014-12-28 10:54:10 Wain

我有一個restaurantEntity與menuComponentEntity有關係。在我的responseDescriptor中，我提供了我的restaurantMapping和一個webApi url。 restaurantManager在沒有任何問題的情況下加載所有數據。選項'valueTransformerWithValidationBlock'調用兩次：第一次目的地是NSString類，sourceClass是NCSFString類，第二次destinationClass是NSNumber類，源類是'NSCFNumber'類，但轉換類不被調用。如果例如將自定義值轉換器添加到另一個屬性（如「name」），則會調用變換塊！ – 2014-12-28 19:46:56

打開跟蹤日誌記錄。數據模型中設置了哪種數據類型？而託管對象類是自動生成的？ – Wain 2014-12-28 22:45:28

Restkit：RKValueTransformer transformationBlock不叫

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