如何保存核心數據與XML解析器

Question

我做了這個XML解析器：

XMLToObjectParser.m：

#import "XMLToObjectParser.h" 

@implementation XMLToObjectParser 

- (id)init 
{ 
    self = [super init]; 
    if (self) { 
     // Initialization code here. 
    } 

    return self; 
} 

- (NSArray *)items 
{ 
    return items; 
} 

- (id)parseXMLAtURL:(NSURL *)url 
      toObject:(NSString *)aClassName 
     parseError:(NSError **)error 
{ 
    //[items release]; 
    items = [[NSMutableArray alloc] init]; 
    className = aClassName; 
    NSXMLParser *parser = [[NSXMLParser alloc] initWithContentsOfURL:url]; 
    [parser setDelegate:self]; 
    [parser parse]; 

    if([parser parserError] && error) { 
     *error = [parser parserError]; 
    } 
    //[parser release]; 
    return self; 
} 

- (void)parser:(NSXMLParser *)parser 
didStartElement:(NSString *)elementName 
    namespaceURI:(NSString *)namespaceURI 
qualifiedName:(NSString *)qName 
    attributes:(NSDictionary *)attributeDict 
{ 
    if([elementName isEqualToString:className]) { 
     // create an instance of a class on run-time 
     item = [NSEntityDescription entityForName:className inManagedObjectContext:managedObjectContext]; 
    } 
    else { 
     currentNodeName = [elementName copy]; 
     currentNodeContent = [[NSMutableString alloc] init]; 
    } 
} 

- (void)parser:(NSXMLParser *)parser 
didEndElement:(NSString *)elementName 
    namespaceURI:(NSString *)namespaceURI 
qualifiedName:(NSString *)qName 
{ 
    //NSLog(@"Close tag: %@", elementName); 
    if([elementName isEqualToString:className]) { 
     [items addObject:item]; 
     //[item release]; 
     item = nil; 
    } 
    else if([elementName isEqualToString:currentNodeName]) { 
     // use key-value coding 
     [item setValue:currentNodeContent forKey:elementName]; 

     //[currentNodeContent release]; 
     currentNodeContent = nil; 

     //[currentNodeName release]; 
     currentNodeName = nil; 
    } 
} 

- (void)parser:(NSXMLParser *)parser 
foundCharacters:(NSString *)string 
{ 
    [currentNodeContent appendString:string]; 
} 

- (void)dealloc 
{ 
    //[items release]; 
    //[super dealloc]; 
} 

@end 

XMLToObjectParser.h：

#import <Foundation/Foundation.h> 

@interface XMLToObjectParser : NSObject <NSXMLParserDelegate> { 
    NSString *className; 
    NSMutableArray *items; 
    NSObject *item; // stands for any class 
    NSString *currentNodeName; 
    NSMutableString *currentNodeContent; 
    NSManagedObjectContext *managedObjectContext; 
} 

- (NSArray *)items; 
- (id)parseXMLAtURL:(NSURL *)url 
      toObject:(NSString *)aClassName 
     parseError:(NSError **)error; 

@end 

它解析像這樣的XML ：

<section id="2"> 
    <label>Animaux</label> 
    <image>Images/Rayons/Bandeau/Animaux.png</image> 
    <key>Images/Rayons/Bandeau/Animaux.png</key> 
    <products> 
    <Product id="21"> 
     <category_id>Chat</category_id> 
     <label>Aliments pour chat</label> 
     <price>2.00</price> 
    </Product> 
    <Product id="1286"> 
     <category_id>Chat</category_id> 
     <label>Boite de paté</label> 
     <price>0.00</price> 
    </Product> 
    </products> 
</sections> 

但它在t上崩潰他行

item = [NSEntityDescription entityForName:className inManagedObjectContext:managedObjectContext]; 

任何人都可以幫我嗎？

謝謝

Answer 1

我沒看過的所有代碼貼出來，但我認爲你正在尋找這個方法：

[NSEntityDescription insertNewObjectForEntityForName:name 
        inManagedObjectContext:ctx]; 

+entityForName:只得到實體描述（NSEntityDescription型的），但你試圖創建一個對象。