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问iPhone -数据库读取方法和内存泄漏
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Stack Overflow用户

提问于 2010-04-20 23:27:01

回答 3查看 963关注 0票数 0

在我的应用程序中，一个RSS阅读器，我得到了内存泄漏，我无法修复，因为我不能理解它们来自哪里。以下是Instruments指出的代码。

-(void) readArticlesFromDatabase {



[self setDatabaseInfo];

 sqlite3 *database;

 articles = [[NSMutableArray alloc] init];

 if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) {
  const char *sqlStatement = "select * from articles";
  if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) {
   while(sqlite3_step(compiledStatement) == SQLITE_ROW) {

    NSString *aName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)];
    NSString *aDate = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 2)];
    NSString *aUrl = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 3)];
    NSString *aCategory = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 4)];
    NSString *aAuthor = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 5)];
    NSString *aSummary = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 6)];
    NSMutableString *aContent = [NSMutableString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 7)];
    NSString *aNbrComments = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 8)];
    NSString *aCommentsLink = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 9)];
    NSString *aPermalink = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 11)];

    [aContent replaceCharactersInRange: [aContent rangeOfString: @"http://www.mywebsite.com/img/action-on.gif"] withString: @"hellocoton-action-on.gif"];
    [aContent replaceCharactersInRange: [aContent rangeOfString: @"hhttp://www.mywebsite.com/img/action-on-h.gif"] withString: @"hellocoton-action-on-h.gif"];
    [aContent replaceCharactersInRange: [aContent rangeOfString: @"hthttp://www.mywebsite.com/img/hellocoton.gif"] withString: @"hellocoton-hellocoton.gif"];

    NSString *imageURLBrut = [self parseArticleForImages:aContent];    
    NSString *imageURLCache = [imageURLBrut stringByReplacingOccurrencesOfString:@":" withString:@"_"];
    imageURLCache = [imageURLCache stringByReplacingOccurrencesOfString:@"/" withString:@"_"];
    imageURLCache = [imageURLCache stringByReplacingOccurrencesOfString:@" " withString:@"_"];

    NSString *uniquePath = [tmp stringByAppendingPathComponent: imageURLCache];
    if([[NSFileManager defaultManager] fileExistsAtPath: uniquePath]) {
     imageURLCache = [@"../tmp/" stringByAppendingString: imageURLCache];
     [aContent replaceCharactersInRange: [aContent rangeOfString: imageURLBrut ] withString: imageURLCache];
    }

    Article *article = [[Article alloc] initWithName:aName date:aDate url:aUrl category:aCategory author:aAuthor summary:aSummary content:aContent commentsNbr:aNbrComments commentsLink:aCommentsLink commentsRSS:@"" enclosure:aPermalink enclosure2:@"" enclosure3:@""];

    [articles addObject:article];

    article = nil;
    [article release];
   }
  }
  sqlite3_finalize(compiledStatement);

 }
 sqlite3_close(database);
}

我有很多“文章”泄漏和NSString匹配这些使用：

[NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, X)];

我尝试了很多不同的代码，我总是有这些漏洞。有谁有办法帮我吗？

nsstring

memory-leaks

iphone

database

回答 3

Stack Overflow用户

发布于 2010-04-20 23:35:59

你泄露文章是因为：

article = nil;
[article release];

为什么你要尝试释放nil？

只需删除行设置为nil的文章，它是不需要的。根据上面的示例，该代码中可能存在更多问题。

票数 1

Stack Overflow用户

发布于 2010-06-09 08:58:39

我只是花了几天的时间来追踪这个问题，并在下面为我解决了这个问题。

将dealloc方法添加到您的文章NSObject并释放所有字符串。然后在您的readArticlesFromDatabase方法中，首先发布文章，然后执行初始化。

票数 1

Stack Overflow用户

发布于 2010-04-26 19:26:24

我终于自己找到了解决方案的一部分。

我的错误是将“文章”数组初始化到我的函数中。实际上，每次我调用我的函数时，我都会丢失这个数组中的前一个数据。现在，我在启动时初始化了“文章”数组，并简单地在我的函数中删除了它的内容：

- (void)applicationDidFinishLaunching:(UIApplication *)application {
       // My Code
       articles = [[NSMutableArray alloc] init];
       // My Code
}

然后

-(void) readArticlesFromDatabase {

    [self setDatabaseInfo];
    sqlite3 *database;

    [articles removeAllObjects];

    if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) {
        const char *sqlStatement = "select * from articles";
        sqlite3_stmt *compiledStatement;
        if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) {
            while(sqlite3_step(compiledStatement) == SQLITE_ROW) {

                NSString *aName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)];
                NSString *aDate = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 2)];
                NSString *aUrl = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 3)];
                NSString *aCategory = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 4)];
                NSString *aAuthor = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 5)];
                NSString *aSummary = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 6)];
                NSMutableString *aContent = [NSMutableString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 7)];
                NSString *aNbrComments = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 8)];
                NSString *aCommentsLink = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 9)];
                NSString *aPermalink = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 11)];

                [aContent stringByReplacingOccurrencesOfString: @"http://www.mywebsite.com/img/action-on.gif" withString: @"hellocoton-action-on.gif"];
                [aContent stringByReplacingOccurrencesOfString: @"http://www.mywebsite.com/img/action-on-h.gif" withString: @"hellocoton-action-on-h.gif"];
                [aContent stringByReplacingOccurrencesOfString: @"http://www.mywebsite.com/img/hellocoton.gif" withString: @"hellocoton-hellocoton.gif"];

                NSString *imageURLBrut = [self parseArticleForImages:aContent]; 
                NSString *imageURLCache = [imageURLBrut stringByReplacingOccurrencesOfString:@":" withString:@"_"];
                [imageURLCache stringByReplacingOccurrencesOfString:@"/" withString:@"_"];
                [imageURLCache stringByReplacingOccurrencesOfString:@" " withString:@"_"];

                NSString *uniquePath = [tmp stringByAppendingPathComponent: imageURLCache];
                if([[NSFileManager defaultManager] fileExistsAtPath: uniquePath]) {
                    imageURLCache = [@"../tmp/" stringByAppendingString: imageURLCache];
                    [aContent replaceCharactersInRange: [aContent rangeOfString: imageURLBrut ] withString: imageURLCache];
                }

                Article *article = [[Article alloc] initWithName:aName date:aDate url:aUrl category:aCategory author:aAuthor summary:aSummary content:aContent commentsNbr:aNbrComments commentsLink:aCommentsLink commentsRSS:@"" enclosure:aPermalink enclosure2:@"" enclosure3:@""];

                [articles addObject:article];

                [article release];
            }
        }
        sqlite3_finalize(compiledStatement);
    }
    sqlite3_close(database);
}

现在我要关注的是由文章removeAllObjects引起的“文章”泄漏。如果我不删除所有的对象，我不会有任何泄漏，但如果我删除了，我就会有泄漏。有什么想法吗？如何才能在不泄漏这些文章对象的情况下清空数组？

票数 0

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/2676385

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