Question

我有一个创建本地通知的应用。当应用程序关闭（即未运行或在后台运行）时，它会在从通知启动时崩溃。我已经设法找出崩溃应用程序的哪一行（在下面的评论中说明）：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
// Override point for customization after application launch.
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleBlackOpaque];

// Initialise the main view
self.viewController = [[[ViewController alloc] initWithNibName:@"ViewController" bundle:nil] autorelease];

// Initialise a Navigation Controller
UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:self.viewController];

// Set the ViewController as the rootViewController of the window
self.window.rootViewController = nav;

// Colour the navigation bar
nav.navigationBar.tintColor = [UIColor colorWithRed:0.07f green:0.59f blue:0.94f alpha:1];

// Set the background
if (isPhone568) {
    self.window.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"santa_back5.png"]];
}
else {
    self.window.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"santa_back.png"]];
}

[self.window makeKeyAndVisible];
[nav release];

self.viewController.managedObjectContext = [self managedObjectContext];

application.applicationIconBadgeNumber = 0;

// Handle launching from a notification
UILocalNotification *localNotif = [launchOptions objectForKey:UIApplicationLaunchOptionsLocalNotificationKey];
if (localNotif) {
    NSPredicate *predicate = [NSPredicate
                              predicateWithFormat:@"(dateCreated like %@)",
                              [localNotif.userInfo objectForKey:@"dateCreated"]];

    LetterViewController *letterView = [[LetterViewController alloc] initWithNibName:@"LetterViewController" bundle:nil];

    // Get the letter to pass on
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription
                                   entityForName:@"Letter" inManagedObjectContext:[self managedObjectContext]];
    [fetchRequest setEntity:entity];
    [fetchRequest setPredicate:predicate];
    NSError *error;
//
// THIS NEXT LINE IS CRASHING THE APP
//
    NSArray *letters = [[self managedObjectContext] executeFetchRequest:fetchRequest error:&error];
    Letter *myLetter = [letters objectAtIndex:0];

    letterView.theLetter = myLetter;
    //[myLetter release];

    // Pass the selected object to the new view controller.
    [self.viewController.navigationController pushViewController:letterView animated:YES];
    [letterView release];
    [fetchRequest release];
}

return YES;
}

我使用以下3个函数来获取托管对象上下文，持久性存储协调器和托管对象模型：

//Explicitly write Core Data accessors
- (NSManagedObjectContext *) managedObjectContext {
if (managedObjectContext != nil) {
    return managedObjectContext;
}
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (coordinator != nil) {
    managedObjectContext = [[NSManagedObjectContext alloc] init];
    [managedObjectContext setPersistentStoreCoordinator: coordinator];
}
return managedObjectContext;
}

- (NSManagedObjectModel *)managedObjectModel {
if (managedObjectModel != nil) {
    return managedObjectModel;
}
managedObjectModel = [[NSManagedObjectModel mergedModelFromBundles:nil] retain];

return managedObjectModel;
}

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
if (persistentStoreCoordinator != nil) {
    return persistentStoreCoordinator;
}
NSURL *storeUrl = [NSURL fileURLWithPath: [[self applicationDocumentsDirectory]
                                           stringByAppendingPathComponent: @"<Project Name>.sqlite"]];
NSError *error = nil;
persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc]
                              initWithManagedObjectModel:[self managedObjectModel]];
if(![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType
                                             configuration:nil URL:storeUrl options:nil error:&error]) {
    /*Error for store creation should be handled in here*/
}

return persistentStoreCoordinator;
}

- (NSString *)applicationDocumentsDirectory {
return [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
}

非常感谢任何帮助解决这个问题。

提前致谢。

Answer 1

一些事情。您似乎在所显示的主线程上使用Core Data，如果是这样，所有交互必须在此线程上。您应该有一天更新代码以使用使用块的新“执行”API。

由于你的localNotif代码现在在启动委托中做了一些繁重的工作，它不会返回一段时间，iOS可能会杀死你的应用程序。获取相同的代码并将其放入发布到主队列的调度块中，它应该可以工作。添加一些断言以确保导航控制器属性也存在。

Answer 2

感谢您的回答。似乎我的问题与谓词有关！它不喜欢我在where子句中使用“like”。我将它改为=并且它有效！

iOS - 从本地通知启动时，托管对象上下文会崩溃应用程序

2 个答案: