我有一个在旧项目中运行良好的应用程序（不使用ARC，而是在iOS 4.2的Xcode 4.0中编写。
我正在尝试将此应用程序移植到使用ARC和故事板与Xcode 4.2和iOS 5。
我已经移植了所有内容并修复了由保留，释放，解除分配等引起的所有错误。该项目现在构建良好。我还在新项目中重建了我的Core Data模型并重建了我的模型子类。
错误发生的地方是我尝试在后台线程中解析XML文件。该文件是项目的本地文件。我为执行解析的每个NSOperation类NSLog初始化器（其中有四个）。我到了应用程序的那一点，当我将操作添加到队列时发生错误。
以下是AppDelegate中启动操作的代码：
#import "AppDelegate.h"
#import "ACHPhonebook.h"
@implementation AppDelegate
@synthesize window = _window;
@synthesize managedObjectContext = __managedObjectContext;
@synthesize managedObjectModel = __managedObjectModel;
@synthesize persistentStoreCoordinator = __persistentStoreCoordinator;
@synthesize parseQueue;
@synthesize parseOpAD, parseOpEK, parseOpLR, parseOpSZ;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"ACHPhonebook" inManagedObjectContext:self.managedObjectContext];
[request setEntity:entity];
NSError *error = nil;
NSUInteger count = [self.managedObjectContext countForFetchRequest:request error:&error];
NSLog(@"total CD count = %d", count);
if(
getenv("NSZombieEnabled") || getenv("NSAutoreleaseFreedObjectCheckEnabled")
) {
NSLog(@"NSZombieEnabled/NSAutoreleaseFreedObjectCheckEnabled enabled!");
}
if (count == 0) {
// Purge the DB
[ACHPhonebook purgePhoneBook:self.managedObjectContext];
// NSLog(@"Just purged the phonebook");
// Set up the NSOperation Queue for the parsing
parseQueue = [[NSOperationQueue alloc] init];
// Make an operation to import the phonebook
//[self setParseOp:[[ParseOperation alloc] initAndStartParse]];
[self setParseOpAD:[[ParseOperationA_D alloc] initAndStartParse]];
[self setParseOpEK:[[ParseOperationE_K alloc] initAndStartParse]];
[self setParseOpLR:[[ParseOperationL_R alloc] initAndStartParse]];
[self setParseOpSZ:[[ParseOperationS_Z alloc] initAndStartParse]];
// [parseQueue addOperation:parseOp];
NSArray *opArray = [[NSArray alloc] initWithObjects:parseOpAD, parseOpEK, parseOpLR, parseOpSZ, nil];
[parseQueue addOperations:opArray waitUntilFinished:NO];
}
// self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// // Override point for customization after application launch.
// self.window.backgroundColor = [UIColor whiteColor];
// [self.window makeKeyAndVisible];
return YES;
}
这是NSOperation类中的一个（它们都是相同的，只是处理不同的文件，以帮助加快6000条记录的初始加载。
#import "ParseOperationA-D.h"
#import "ACHPhonebook.h"
#import "AppDelegate.h"
#import "TBXML.h"
@implementation ParseOperationA_D
- (id)initAndStartParse
{
NSLog(@"ParseOperation init");
// [self parsePhonebook];
return self;
}
- (void)mergeChanges:(NSNotification *)notification
{
id appDelegate = [[UIApplication sharedApplication] delegate];
NSManagedObjectContext *mainContext = [appDelegate managedObjectContext];
// Merge changes into the main context on the main thread
[mainContext performSelectorOnMainThread:@selector(mergeChangesFromContextDidSaveNotification:)
withObject:notification
waitUntilDone:NO];
// NSLog(@"Merged Changes");
}
// the main function for this NSOperation, to start the parsing
- (void)main {
id appDelegate = [[UIApplication sharedApplication] delegate];
NSManagedObjectContext *ctx = [[NSManagedObjectContext alloc] init];
[ctx setUndoManager:nil];
[ctx setPersistentStoreCoordinator: [appDelegate persistentStoreCoordinator]];
// Register context with the notification center
NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
[nc addObserver:self
selector:@selector(mergeChanges:)
name:NSManagedObjectContextDidSaveNotification
object:ctx];
NSUInteger x = 1;
TBXML *tbxml = [[TBXML alloc] initWithXMLFile:@"achcentral_aTOd.xml"];
// Get root element
TBXMLElement * root = tbxml.rootXMLElement;
// if root element is valid
if (root) {
NSError *error = nil;
TBXMLElement *thisPBE = [TBXML childElementNamed:@"PhoneBookResults" parentElement:root];
while (thisPBE != nil) {
// Set up the Insert command
ACHPhonebook * xmlPBE = (ACHPhonebook *)[NSEntityDescription insertNewObjectForEntityForName:@"ACHPhonebook" inManagedObjectContext:ctx];
// Set all the field values from the XML record
// TBXMLElement *elName = [TBXML childElementNamed:@"Name" parentElement:thisPBE];
// if (elName != nil) {
// [xmlPBE setName:[TBXML textForElement:elName]];
// }
TBXMLElement *elTitle = [TBXML childElementNamed:@"title" parentElement:thisPBE];
if (elTitle != nil) {
[xmlPBE setTitle:[TBXML textForElement:elTitle]];
}
TBXMLElement *elDept = [TBXML childElementNamed:@"department" parentElement:thisPBE];
if (elDept != nil) {
// obtain the text from the description element
[xmlPBE setDepartment:[TBXML textForElement:elDept]];
}
TBXMLElement *elExt = [TBXML childElementNamed:@"phone" parentElement:thisPBE];
if (elExt != nil) {
[xmlPBE setExt:[TBXML textForElement:elExt]];
}
TBXMLElement *elPager = [TBXML childElementNamed:@"pager" parentElement:thisPBE];
if (elPager != nil) {
[xmlPBE setPager:[TBXML textForElement:elPager]];
}
TBXMLElement *elEmailAddress = [TBXML childElementNamed:@"emailaddress" parentElement:thisPBE];
if (elEmailAddress != nil) {
[xmlPBE setEmailAddress:[TBXML textForElement:elEmailAddress]];
}
// TBXMLElement *elNetworkID = [TBXML childElementNamed:@"NetworkID" parentElement:thisPBE];
// if (elNetworkID != nil) {
// [xmlPBE setNetworkid:[TBXML textForElement:elNetworkID]];
// }
TBXMLElement *elLastName = [TBXML childElementNamed:@"lastName" parentElement:thisPBE];
if (elLastName != nil) {
[xmlPBE setLastName:[TBXML textForElement:elLastName]];
}
TBXMLElement *elFirstName = [TBXML childElementNamed:@"firstName" parentElement:thisPBE];
if (elFirstName != nil) {
[xmlPBE setFirstName:[TBXML textForElement:elFirstName]];
}
if (elFirstName != nil && elLastName !=nil) {
// Make the name field from the first and last names
NSString *fullName = [[TBXML textForElement:elFirstName] stringByAppendingFormat:@" %@",[TBXML textForElement:elLastName]];
[xmlPBE setName:fullName];
}
TBXMLElement *elPicLoc = [TBXML childElementNamed:@"picFileName" parentElement:thisPBE];
if (elPicLoc != nil) {
if (![[TBXML textForElement:elPicLoc] isEqualToString:@""])
{
[xmlPBE setPicloc:[TBXML textForElement:elPicLoc]];
NSString *picFilePath = @"https://secure.archildrens.org/insite/badgepics/adbadgepics/";
NSURL *url = [NSURL URLWithString:[picFilePath
stringByAppendingString:xmlPBE.picloc]];
NSData * imageData = [[NSData alloc] initWithContentsOfURL: url];
if (!imageData)
{
// The image filename was stored but didn't exist
NSString *achImage =
[[NSBundle mainBundle] pathForResource:@"ach" ofType:@"png"];
imageData = [NSData dataWithContentsOfFile:achImage];
}
[xmlPBE setPicture:imageData];
}
}
if (x % 50 == 0) {
// Get ready to save the context
error = nil;
// Save the context.
if (![ctx save:&error])
{
NSLog(@"loadPhoneBook error %@, %@", error, [error userInfo]);
abort();
}
// Clear out the scratchpad
[ctx reset];
//NSLog(@"Got 10");
}
// Find the next XML record (this will end the while loop when we reach the end)
thisPBE = [TBXML nextSiblingNamed:@"PhoneBookResults" searchFromElement:thisPBE];
// Increment the counter
x++;
} // while ...
if ([ctx hasChanges]) {
// NSUInteger *left = [[ctx insertedObjects] count];
error = nil;
// Save the context.
if (![ctx save:&error])
{
NSLog(@"loadPhoneBook error %@, %@", error, [error userInfo]);
abort();
}
// Clear out the scratchpad
[ctx reset];
NSLog(@"Got the last ones, %d", x);
}
}
}
@end
我已尝试启用NSZombies但仍无法看到发生了什么。它始终在
EXC_BAD_ACCESS错误
[parseQueue addOperations:opArray waitUntilFinished:NO];
AppDelegate中行，这是我在iOS应用中首次尝试多线程。就像我之前说的那样，我有一个运行版本，它是针对旧版SDK而构建的，它仍在运行。这可能是（也可能是）我忽略的非常简单的事情......
答案 0 :(得分：6)
在调试器中设置MallocStackLogging，guard malloc和（您可能已经完成此操作）NSZombieEnabled。然后，当您的应用程序崩溃时，请在gdb控制台中输入：
(gdb) info malloc-history 0x543216
将0x543216替换为导致崩溃的对象的地址，您将获得更有用的堆栈跟踪，它可以帮助您查明代码中导致问题的确切行。
答案 1 :(得分：0)
没有使用NSOperations，你试过self performSelectorInBackground：withObject：？