Question

iOS初学者。我正在尝试为新闻网站创建一个RSS阅读器，RSS解析器处于正常工作状态，但如果它是在启用ARC的情况下编译的，它会给出异常EXC_BAD_ACCESS（代码= 2地址= 0xc）。

以下是我调用解析器的方法:(在我的视图控制器中）

NSMutableArray* articleListMainPage;

- (void)viewDidLoad
{
    NSURL *mainFeed = [[NSURL alloc]initWithString:@"http://my.domain.com/rss.xml"];
    NSXMLParser *nsXmlParser = [[NSXMLParser alloc] initWithContentsOfURL:mainFeed];
    NewsParser *myparser = [[NewsParser alloc] initNewsParser];
    [nsXmlParser setDelegate:myparser];

    if ([nsXmlParser parse]) {
        NSLog(@"Parsed article count : %i", [myparser.articles count]);
        articleListMainPage = [myparser.articles copy];
    } else {
        NSLog(@"Error parsing document!");
    }
    nsXmlParser = nil;
    mainFeed = nil;
    myparser = nil; // This line throws the exception.

    [super viewDidLoad];
}

这是解析器本身：

// NewsParser.m
#import "NewsParser.h"
#import "RSSEntry.h"

@implementation NewsParser

@synthesize article, articles, currValue;

- (NewsParser *) initNewsParser
{
    if (self = [super init]) return self; else return nil;
}

- (void)parser:(NSXMLParser *)parser
    didStartElement:(NSString *)elementName
    namespaceURI:(NSString *)namespaceURI
    qualifiedName:(NSString *)qualifiedName
    attributes:(NSDictionary *)attributeDict {

    if ([elementName isEqualToString:@"channel"]) {
        self.articles = [[NSMutableArray alloc] init];
    }
    if ([elementName isEqualToString:@"item"]) {
        self.article = [[ArticleEntry alloc] init];
    }
}

- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string {
    if (!currValue) {
        self.currValue = [[NSMutableString alloc] initWithString:string];
    } else {
        [self.currValue appendString:string];
    }
}

- (void)parser:(NSXMLParser *)parser
    didEndElement:(NSString *)elementName
     namespaceURI:(NSString *)namespaceURI
    qualifiedName:(NSString *)qName {

    if ([elementName isEqualToString:@"channel"]) {
        return;
    }

    if ([elementName isEqualToString:@"item"]) {
        [self.articles addObject:self.article];
        self.article = nil;
    } else {
        if ([[NSArray arrayWithObjects:@"title",@"link",@"description",nil] containsObject:elementName])
             [self.article setValue:self.currValue forKey:elementName];
    }
    self.currValue = nil;
}

@end

//NewsParser.h

#import <Foundation/Foundation.h>
#import "RSSEntry.h"

@interface NewsParser : NSXMLParser <NSXMLParserDelegate> {
    NSMutableString *currValue;
    NSMutableArray *articles;
    ArticleEntry *article;
}
- (NewsParser *) initNewsParser;
@property (nonatomic,retain) ArticleEntry *article;
@property (nonatomic,retain) NSMutableArray *articles;
@property (nonatomic,retain) NSMutableString *currValue;
@end

..和我用来存储RSS条目的类。

//RSSEntry.h
#import <Foundation/Foundation.h>

@interface ArticleEntry : NSObject {
    NSString *title;
    NSString *link;
    NSString *description;
}

@property (nonatomic, retain) NSString *title;
@property (nonatomic, retain) NSString *link;
@property (nonatomic, retain) NSString *description;

- (id)initNewArticle:(NSString*)_title url:(NSString*)_link description:(NSString*)_desc;

@end

//RSSEntry.m

#import "RSSEntry.h"

@implementation ArticleEntry
@synthesize title,link,description;
- (id)initNewArticle:(NSString *)_title url:(NSString *)_link description:(NSString *)_desc
{
    if ((self = [super init])) {
        title = [_title copy];
        link = [_link copy];
        description = [_desc copy];
        return self;
    }
    else return nil;
}
@end

就像我说的那样，如果没有ARC，它可以正常工作，但我想知道我是否正在做一些我不应该做的事情（例如保留一些我不应该做的事情或者没有正确释放某些东西/过度发布的东西）代码。

谢谢你的时间..

Answer 1

这里的一个问题是你声明NewsParser是NSXMLParser的子类，它不应该是。它应该是NSObject的子类（或其他适当的）

所以在NewsParser.h中，试试这个：

@interface NewsParser : NSObject <NSXMLParserDelegate>

顺便说一下，没有ARC，你确实有内存泄漏。如果您打算在没有ARC的情况下再次编译此代码，分析器可以帮助您解决这些问题。有或没有ARC，这里没有垃圾收集器（听起来好像你指望一个？）

启用ARC时，NSXMLParser会抛弃EXC_BAD_ACCESS

1 个答案: