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我正在尝试通过 MfMail Composer 发送一个 CSV 文件。一切正常，但使用 Instruments 时有很多泄漏。我无法找出我出错的地方。这是我的代码。

-(NSData *)getCSV
{
NSManagedObjectContext *moc = [(ETAppDelegate *)[[UIApplication sharedApplication] delegate]managedObjectContext];
NSFetchRequest *request = [[[NSFetchRequest alloc]init]autorelease];
[request setEntity:[NSEntityDescription entityForName:@"Expense" inManagedObjectContext:moc]];
NSError *error = nil;
NSArray *results = [moc executeFetchRequest:request error:&error];
NSMutableArray *expensesList = [[[NSMutableArray alloc]init]autorelease];
for(int i = 0;i<[results count];i++){
    NSString *category = [[results objectAtIndex:i]valueForKey:@"category"];
    NSString *date = [[NSDateFormatter dateFormatterwithMediumStyle]stringFromDate:[[results objectAtIndex:i]valueForKey:@"date"]];
    NSString *amount = [NSNumberFormatter localizedStringFromNumber:[[results objectAtIndex:i]valueForKey:@"amount"] numberStyle:NSNumberFormatterCurrencyStyle];
    NSString *mailString = [NSString stringWithFormat:@"%@,%@,%@",category,date,amount ];
    [expensesList addObject:mailString];
}
NSString *expensesString = [expensesList componentsJoinedByString:@"\n"];
NSData *expensesData = [expensesString dataUsingEncoding:NSUTF8StringEncoding];
return expensesData;
}


-(void)displayComposerSheet
{
NSData *csvFile = [self getCSV];
NSString *csvFileName = @"MyExpenses";
MFMailComposeViewController *mailController = [[MFMailComposeViewController alloc]init];
[mailController setSubject:@"List Of Expenses"];
[mailController setMessageBody:@"Expenses" isHTML:NO];
[mailController addAttachmentData:csvFile mimeType:@"text/csv" fileName:csvFileName];
[mailController setMailComposeDelegate:self];
[self presentModalViewController:mailController animated:YES];
[mailController release];
 }
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1 回答 1

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我不能说我在您提供的代码中看到了任何会导致您泄漏的内容。您的泄漏可能发生在其他地方。

然而，我确实看到的是，在 中的该循环中创建大量自动释放对象的潜力-getCSV，并且取决于您正在执行的迭代次数，这可能几乎同样糟糕。按照您编写的方式，我看到一个日期格式化程序和三个字符串在每次迭代中都指向您的主自动释放池。一个建议是在循环之外创建一个日期格式化程序，您可以在其中重复使用它。另一个建议是使用本地自动释放池来构建循环的核心；这将防止您的主自动释放池变得太大。

顺便说一句，您还应该考虑使用快速枚举。

这是应用了建议的循环：

NSDateFormatter *myDateFormatter = [NSDateFormatter dateFormatterWithMediumStyle];

NSMutableArray *expensesList = [[[NSMutableArray alloc] init] autorelease];
for (id obj in results)
{
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

    NSString *category = [obj valueForKey:@"category"];
    NSString *date = [myDateFormatter stringFromDate:[obj valueForKey:@"date"]];
    NSString *amount = [NSNumberFormatter localizedStringFromNumber:[obj valueForKey:@"amount"] numberStyle:NSNumberFormatterCurrencyStyle];
    NSString *mailString = [NSString stringWithFormat:@"%@,%@,%@", category, date, amount];

    [expensesList addObject:mailString];

    [pool release];
}
于 2013-04-29T14:54:50.223 回答