Question

我正在开发我的第一个iCloud应用程序。工作一段时间后，由于＆＃34; UIDocumentStateSavingError＆＃34;，应用程序无法再访问UIManagedDocument。有没有办法真正找出发生了什么错误？

这是我创建UIManagedDocument的代码：

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    iCloudURL = [[NSFileManager defaultManager] URLForUbiquityContainerIdentifier:nil];

    if (iCloudURL == nil) {
        dispatch_async(dispatch_get_main_queue(), ^{
            [self iCloudNotAvailable];
        });
        return;
    }


    iCloudDocumentsURL = [iCloudURL URLByAppendingPathComponent:@"Documents"];
    iCloudCoreDataLogFilesURL = [iCloudURL URLByAppendingPathComponent:@"TransactionLogs"];

    NSURL *url = [iCloudDocumentsURL URLByAppendingPathComponent:@"CloudDatabase"];
    iCloudDatabaseDocument = [[UIManagedDocument alloc] initWithFileURL:url];

    NSMutableDictionary *options = [NSMutableDictionary dictionary];

    NSString *name = [iCloudDatabaseDocument.fileURL lastPathComponent];
    [options setObject:name forKey:NSPersistentStoreUbiquitousContentNameKey];
    [options setObject:iCloudCoreDataLogFilesURL forKey:NSPersistentStoreUbiquitousContentURLKey];

    iCloudDatabaseDocument.persistentStoreOptions = options;

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(documentContentsChanged:) name:NSPersistentStoreDidImportUbiquitousContentChangesNotification object:iCloudDatabaseDocument.managedObjectContext.persistentStoreCoordinator];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(documentStateChanged:) name:UIDocumentStateChangedNotification object:iCloudDatabaseDocument];


    if ([[NSFileManager defaultManager] fileExistsAtPath:[iCloudDatabaseDocument.fileURL path]]) {
        // This is true, the document exists.
        if (iCloudDatabaseDocument.documentState == UIDocumentStateClosed) {
            [iCloudDatabaseDocument openWithCompletionHandler:^(BOOL success) {
                if (success) {
                    dispatch_async(dispatch_get_main_queue(), ^{
                        [self documentConnectionIsReady];
                    });
                } else {
                    dispatch_async(dispatch_get_main_queue(), ^{
                        [self connectionError:iCloudConnectionErrorFailedToOpen];
                    });
                }
            }];                    
        } else if (iCloudDatabaseDocument.documentState == UIDocumentStateNormal) {
            ...
        }      
    } else {
        ...               
    }           
});

文档已经存在，因此在文档上调用openWithCompletionHandler :.这会失败并触发UIDocumentStateChangedNotification，显示文档状态为5： UIDocumentStateClosed和 UIDocumentStateSavingError

在此之后调用完成块。从这里开始的正确方法是什么？有没有办法找出出了什么问题以及发生了什么样的错误？

我试图在完成块中重新打开文档，但结果是一样的。

我想我可以通过删除文件并重新创建它来解决问题。但是，一旦应用程序出现在商店中，这显然不是一种选择。我想知道出了什么问题，并给用户一个合适的方法来处理问题。

我已经在这里检查过处理UIDocumentStateSavingError的其他问题（其中不是很多）但似乎不适用于此处的问题。

知道如何找出问题所在吗？我不能相信API告诉你＆＃34;保存期间出了问题，但我不会告诉你什么！＆＃34;

Answer 1

您可以在完成处理程序中查询documentState。不幸的是，如果你想要确切的错误，获得它的唯一方法是子类化并覆盖handleError：userInteractionPermitted：

也许这样的东西会有所帮助（没有编译器的徒手打字）......

@interface MyManagedDocument : UIManagedDocument
 - (void)handleError:(NSError *)error
         userInteractionPermitted:(BOOL)userInteractionPermitted;
@property (nonatomic, strong) NSError *lastError;
@end

@implementation MyManagedDocument
@synthesize lastError = _lastError;
 - (void)handleError:(NSError *)error
         userInteractionPermitted:(BOOL)userInteractionPermitted
{
    self.lastError = error;
    [super handleError:error
           userInteractionPermitted:userInteractionPermitted];
}
@end

然后你可以像这样创建它......

iCloudDatabaseDocument = [[UIManagedDocument alloc] initWithFileURL:url];

并在像这样的完成处理程序中使用它......

        [iCloudDatabaseDocument openWithCompletionHandler:^(BOOL success) {
            if (success) {
                dispatch_async(dispatch_get_main_queue(), ^{
                    [self documentConnectionIsReady];
                });
            } else {
                dispatch_async(dispatch_get_main_queue(), ^{
                    [self connectionError:iCloudConnectionErrorFailedToOpen
                                withError:iCloudDatabaseDocument.lastError];
                });
            }
        }];

Answer 2

基于@JodyHagins优秀代码段，我创建了一个UIDocument子类。

@interface SSDocument : UIDocument
- (void)openWithSuccess:(void (^)())successBlock
           failureBlock:(void (^)(NSError *error))failureBlock;
@end


@interface SSDocument ()
@property (nonatomic, strong) NSError *lastError;
@end

@implementation SSDocument

- (void)handleError:(NSError *)error userInteractionPermitted:(BOOL)userInteractionPermitted {
    self.lastError = error;
    [super handleError:error userInteractionPermitted:userInteractionPermitted];
}

- (void)clearLastError {
    self.lastError = nil;
}

- (void)openWithSuccess:(void (^)())successBlock failureBlock:(void (^)(NSError *error))failureBlock {
    NSParameterAssert(successBlock);
    NSParameterAssert(failureBlock);
    [self clearLastError];
    [self openWithCompletionHandler:^(BOOL success) {
        if (success) {
            successBlock();
        } else {
            NSError *error = self.lastError;
            [self clearLastError];
            failureBlock(error);
        }
    }];
}

@end

UIManagedDocument - 如何处理UIDocumentStateSavingError？

2 个答案: