解决 Cocoa 中的 EXC_BAD_ACCESS 问题？

嘿..我在可可中有以下方法..

-(void)startUploadWithContainerName:(NSString *)containerName
{
//Make an object of NSFileManager and Fetch an array of local folder contents and cloud folder contents
NSFileManager *uploadManager=[[NSFileManager alloc] init];
NSString *uploadPath=[[[NSString alloc] initWithString:@"~/Cloud Briefcase"] stringByExpandingTildeInPath];
NSError *err;
NSArray *uploadFolderContents=[uploadManager contentsOfDirectoryAtPath:uploadPath error:&err];
ASICloudFilesObjectRequest *cloudList = [ASICloudFilesObjectRequest listRequestWithContainer:containerName];
[cloudList startSynchronous];
NSArray *cloudFolderContents = [cloudList objects];

[cloudList release];
[uploadManager release];

NSLog(@"%lu",[uploadFolderContents count]);
NSLog(@"\n%@\n\n%@",cloudFolderContents,uploadFolderContents);
NSString *notFoundPath;
NSString *foundPath;
NSString *foundCloudMatch;
NSDate *cloudUploadDate;

for (int j=1; j<[uploadFolderContents count]; j++) {
    int i=0;
    for (int k=0; k<[cloudFolderContents count]; k++) {
        if ([[[cloudFolderContents objectAtIndex:k] name] isEqualToString:[uploadFolderContents objectAtIndex:j]]) {
            i=1;
            foundPath=[uploadFolderContents objectAtIndex:j];
            foundCloudMatch=[cloudFolderContents objectAtIndex:k];
            cloudUploadDate=[[cloudFolderContents objectAtIndex:k] lastModified];
            break;
        }
        else{
            i=0;
            notFoundPath=[uploadFolderContents objectAtIndex:j];
            continue;
        }
    }

    if (i==1) {
        NSLog(@"Found In Cloud: %@",foundPath);
        NSString *uploadPath=[[NSString stringWithFormat:@"~/Cloud Briefcase/%@",foundPath] stringByExpandingTildeInPath];
        NSTimeZone *tCST=[NSTimeZone timeZoneWithAbbreviation:@"CST"];
        NSInteger cloudDifference=[tCST secondsFromGMTForDate:cloudUploadDate];

        NSFileManager *typeManager=[[NSFileManager alloc] init];
        NSError *Er;
        NSDictionary *propertiesOfUploadFile=[typeManager attributesOfItemAtPath:uploadPath error:&Er];

        NSDate *localUploadDate=[propertiesOfUploadFile objectForKey:NSFileModificationDate];

        NSInteger sourceUploadDifference=[[NSTimeZone systemTimeZone] secondsFromGMTForDate:localUploadDate];


        NSLog(@"Local Date %@",localUploadDate);
        NSLog(@"Local Difference %ld",sourceUploadDifference);
        NSTimeInterval diff=sourceUploadDifference-cloudDifference;
        NSTimeInterval sDiff=sourceUploadDifference;
        NSDate *lDate=[[NSDate alloc] initWithTimeInterval:sDiff sinceDate:localUploadDate];
        NSDate *comparisonDate=[[NSDate alloc] initWithTimeInterval:diff sinceDate:cloudUploadDate];
        NSLog(@"\nSDiff Value %@",lDate);
        NSLog(@"Comparison Date %@",comparisonDate);

        [localUploadDate release];
        [propertiesOfUploadFile release];
        [typeManager release];
        [tCST release];

        if ([comparisonDate compare:lDate]==NSOrderedAscending) {
            [comparisonDate release];
            [lDate release];
            NSLog(@"Got It");
            NSString *escString=[foundPath stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding];
            ASICloudFilesObjectRequest *request = 
            [ASICloudFilesObjectRequest putObjectRequestWithContainer:containerName objectPath:escString contentType:@"file" file:uploadPath metadata:nil etag:nil];
            [request startSynchronous];
            NSLog(@"Uploaded %@",foundPath);
        }



    }
    else{
        NSLog(@"Not Found In Cloud: %@",notFoundPath);
        NSString *uploadPath=[[NSString stringWithFormat:@"~/Cloud Briefcase/%@",notFoundPath] stringByExpandingTildeInPath];
        //          NSLog(@"%@",uploadPath);


        NSString *escString=[notFoundPath stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding];
        NSLog(@"URL ENCODED VALUE: %@",escString);

        ASICloudFilesObjectRequest *request = 
        [ASICloudFilesObjectRequest putObjectRequestWithContainer:containerName objectPath:escString contentType:@"file" file:uploadPath metadata:nil etag:nil];
        [request startSynchronous];
        NSLog(@"Upload Complete");
    }
}
[uploadPath release];

[cloudList release];
[uploadFolderContents release];

 }

但它挂起显示异常

收到信号 EXC_BAD_ACCESS

有人能解决这个问题吗？异常发生在NSLog(@"在云端找到：%@",foundPath);

通常，您会将环境变量 NSZombieEnabled 设置为 YES，然后解决问题。 在你的例子中，我看到你声明了指针，但没有指向任何危险的对象。在 Clang 分析器中运行代码会将其报告为警告。 将这些指针设置为零。您已经声明了字符串指针，但在 for 循环中，如果“if”不为 true，则它会转到 else ，其中 findPath 从未指向任何内容，并且您尝试在 if(i==1) 中访问它

Update:另请考虑 Lou Franco 的答案。他也是对的。您不拥有 cloudList 对象。它是自动释放的，并且您通过将释放消息传递给 cloudList 对象 [cloudList release] 来过度释放它。 在您的情况下，当您释放它时，它可能不会立即崩溃，因为控制位于同一循环中。一旦当前线程自动释放池耗尽，您的代码将因 EXC_BAD_ACCESS 崩溃。

ASICloudFilesObjectRequest *cloudList = [ASICloudFilesObjectRequest listRequestWithContainer:containerName];
[cloudList startSynchronous];
NSArray *cloudFolderContents = [cloudList objects];
[cloudList release];// Remove this line 

Update2:

NSString *uploadPath=[[[NSString alloc] initWithString:@"~/Cloud Briefcase"] stringByExpandingTildeInPath];

将上面的内容改为

NSString *uploadPath=[[NSString stringWithFormat:@"~/Cloud Briefcase"] stringByExpandingTildeInPath];

上面一行中的 uploadPath 仍然指向自动释放的对象。您正在泄漏您创建的字符串。调用release是错误的。因此，删除 [uploadPath release] 和 [cloudList release]，您将一次又一次地发布它。为什么你要释放明显自动释放的对象 uploadFolderContents ？从代码中删除这三行：

[uploadPath release];

[cloudList release];
[uploadFolderContents release];

Update3:修复了过度释放的问题。 if 块中的 updatePath 更改为 updatePathLocal，其中 updatePath 变量与方法范围存在冲突。

-(void)startUploadWithContainerName:(NSString *)containerName
{
//Make an object of NSFileManager and Fetch an array of local folder contents and cloud folder contents
NSFileManager *uploadManager=[[NSFileManager alloc] init];
NSString *uploadPath=[[NSString stringWithFormat:@"~/Cloud Briefcase"] stringByExpandingTildeInPath];
NSError *err = nil;
NSArray *uploadFolderContents=[uploadManager contentsOfDirectoryAtPath:uploadPath error:&err];
ASICloudFilesObjectRequest *cloudList = [ASICloudFilesObjectRequest listRequestWithContainer:containerName];
[cloudList startSynchronous];
NSArray *cloudFolderContents = [cloudList objects];

[uploadManager release];

NSLog(@"%lu",[uploadFolderContents count]);
NSLog(@"\n%@\n\n%@",cloudFolderContents,uploadFolderContents);
NSString *notFoundPath = nil;
NSString *foundPath = nil;
NSString *foundCloudMatch = nil;
NSDate *cloudUploadDate = nil;

for (int j=1; j<[uploadFolderContents count]; j++) {
    int i=0;
    for (int k=0; k<[cloudFolderContents count]; k++) {
        if ([[[cloudFolderContents objectAtIndex:k] name] isEqualToString:[uploadFolderContents objectAtIndex:j]]) {
            i=1;
            foundPath=[uploadFolderContents objectAtIndex:j];
            foundCloudMatch=[cloudFolderContents objectAtIndex:k];
            cloudUploadDate=[[cloudFolderContents objectAtIndex:k] lastModified];
            break;
        }
        else{
            i=0;
            notFoundPath=[uploadFolderContents objectAtIndex:j];
            continue;
        }
    }

    if (i==1) {
        NSLog(@"Found In Cloud: %@",foundPath);
        NSString *uploadPathLocal=[[NSString stringWithFormat:@"~/Cloud Briefcase/%@",foundPath] stringByExpandingTildeInPath];
        NSTimeZone *tCST=[NSTimeZone timeZoneWithAbbreviation:@"CST"];
        NSInteger cloudDifference=[tCST secondsFromGMTForDate:cloudUploadDate];

        NSFileManager *typeManager=[[NSFileManager alloc] init];
        NSError *Er = nil;
        NSDictionary *propertiesOfUploadFile=[typeManager attributesOfItemAtPath:uploadPathLocal error:&Er];

        NSDate *localUploadDate=[propertiesOfUploadFile objectForKey:NSFileModificationDate];

        NSInteger sourceUploadDifference=[[NSTimeZone systemTimeZone] secondsFromGMTForDate:localUploadDate];


        NSLog(@"Local Date %@",localUploadDate);
        NSLog(@"Local Difference %ld",sourceUploadDifference);
        NSTimeInterval diff=sourceUploadDifference-cloudDifference;
        NSTimeInterval sDiff=sourceUploadDifference;
        NSDate *lDate=[[NSDate alloc] initWithTimeInterval:sDiff sinceDate:localUploadDate];
        NSDate *comparisonDate=[[NSDate alloc] initWithTimeInterval:diff sinceDate:cloudUploadDate];
        NSLog(@"\nSDiff Value %@",lDate);
        NSLog(@"Comparison Date %@",comparisonDate);

        [typeManager release];

        if ([comparisonDate compare:lDate]==NSOrderedAscending) {
            [comparisonDate release];
            [lDate release];
            NSLog(@"Got It");
            NSString *escString=[foundPath stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding];
            ASICloudFilesObjectRequest *request = 
            [ASICloudFilesObjectRequest putObjectRequestWithContainer:containerName objectPath:escString contentType:@"file" file:uploadPath metadata:nil etag:nil];
            [request startSynchronous];
            NSLog(@"Uploaded %@",foundPath);
        }
    }
    else{
        NSLog(@"Not Found In Cloud: %@",notFoundPath);
        NSString *uploadPathLocal=[[NSString stringWithFormat:@"~/Cloud Briefcase/%@",notFoundPath] stringByExpandingTildeInPath];
        //          NSLog(@"%@",uploadPath);


        NSString *escString=[notFoundPath stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding];
        NSLog(@"URL ENCODED VALUE: %@",escString);

        ASICloudFilesObjectRequest *request = 
        [ASICloudFilesObjectRequest putObjectRequestWithContainer:containerName objectPath:escString contentType:@"file" file:uploadPathLocal metadata:nil etag:nil];
        [request startSynchronous];
        NSLog(@"Upload Complete");
    }
 }
}