Question

我有一个由fetchedResultsController / UIManagedDocument支持的tableViewController，它使用通过JSON消息从服务器获取的数据。它以斯坦福2011年iPhone编程讲座中使用的TVC为蓝本。程序从服务器加载，更新并完美刷新tableView。但是当我尝试编辑单元格中的信息时，我的结果非常奇怪。

我在类PlugDetailTVC中编辑对象，该类向DataFetcher类发送消息以发送适当的JSON消息。然后通过重新加载整个数据库 getAllPlugsInDocument。一切正常。发送正确的JSON并收到正确的响应。服务器数据库正确更新。在运行getAllPlugsInDocument之后，tableView显示正确的更新信息。然后10-15秒后，程序抛出一个没有错误消息的异常！

UPDate：我对我的代码进行了一次更改，这是对saveToURL.document.fileURL的更改

[self.document saveToURL:document.fileURL forSaveOperation:UIDocumentSaveForOverwriting
                       completionHandler:^(BOOL success) {
                           if (success) {                  
                               NSLog(@"PlugFetcher Document saved"); 
                           } else {                       
                               NSLog(@"PlugFetcher Document was unable to save");
                           }

BUT！我把代码交给其他人运行（xcode 4.2 / iPhone 5.1模拟器与黑客运行iOS 5.1）它完美运行！我然后在我的手机上运行它 - 带iOS 5.1的4S再次完美运行。回到xCode 4.3.1上的iPhone 5.1模拟器 - 同样的旧崩溃，即使在重置内容和设置等之后现在我比以前更加神秘了。

相关代码：

PlugsTableViewController

-(void)setupFetchedResultsController{
    NSManagedObjectContext *context=self.mainDatabase.managedObjectContext;
    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Plug"];
    request.sortDescriptors = [NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES selector:@selector(localizedCaseInsensitiveCompare:)]];
    self.fetchedResultsController= [[NSFetchedResultsController alloc]initWithFetchRequest:request managedObjectContext:context sectionNameKeyPath:nil cacheName:nil];

}

-(void)fetchPlugDataIntoDocument:(UIManagedDocument *)document{
    NSLog(@"fetchPlugDataIntoDocument");
    PlugFetcher *plugFetcher=[PlugFetcher getInstance];
    [plugFetcher getAllTimeZones:document];
    [plugFetcher getAllPlugsInDocument:document];
}
//Open or create document,call setupFetchedResultsController

    -(void)useDocument{
          if (![[NSFileManager defaultManager]fileExistsAtPath:[self.mainDatabase.fileURL path]]) {
            NSLog(@"######## Document Does not exist #########");

            [self.mainDatabase saveToURL:self.mainDatabase.fileURL forSaveOperation:UIDocumentSaveForCreating completionHandler:^(BOOL success) {
            [self setupFetchedResultsController];
            }];
        }else if (self.mainDatabase.documentState==UIDocumentStateClosed){
            NSLog(@"######## Document closed #########");
           [self.mainDatabase openWithCompletionHandler:^(BOOL success) {
            [self setupFetchedResultsController];
             }];

        }else if (self.mainDatabase.documentState==UIDocumentStateNormal){
            NSLog(@"######## Document Normal #########");
           [self setupFetchedResultsController];
        }
        [self fetchPlugDataIntoDocument:self.mainDatabase];
    }

-(void)setmainDatabase:(UIManagedDocument *)mainDatabase{
    if (_mainDatabase!=mainDatabase) {
        _mainDatabase=mainDatabase;
        [self useDocument];
    }
}

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    if (!self.mainDatabase) {
        NSLog(@"######## !self.mainDatabase #########");
        NSURL *url=[[[NSFileManager defaultManager]URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask]lastObject];
        url=[url URLByAppendingPathComponent:@"main Database"];
        self.mainDatabase=[[UIManagedDocument alloc]initWithFileURL:url];
        PlugFetcher *plugFetcher=[PlugFetcher getInstance];
        plugFetcher.context=self.mainDatabase.managedObjectContext;
        plugFetcher.document=self.mainDatabase;

    }
}


PlugFetcher.m

- (void)getAllPlugsInDocument:(UIManagedDocument*)document{
    NSManagedObjectContext *context=[document managedObjectContext];    
    dispatch_queue_t fetchQ=dispatch_queue_create("Data Fetcher", NULL);
    dispatch_async(fetchQ, ^{
        NSDictionary *serverDictionary=[self.serverCommManager getServerPlugList];
        if([[serverDictionary objectForKey:@"success"] isEqualToString:@"true"]){
            NSArray *serverPlugArray=[serverDictionary objectForKey:@"response"];

            [document.managedObjectContext performBlock:^{ // perform in the NSMOC's safe thread (main thread)
                NSEntityDescription *plugEntity = [NSEntityDescription entityForName:@"Plug" inManagedObjectContext:context];
                [self deleteAllObjectsInEntity:plugEntity forPlug:nil inContext:context];  
                NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"TimeZone"];
                request.sortDescriptors = [NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@"utcOffset"
                                                                                                 ascending:YES]];
                NSNumberFormatter * formatter = [[NSNumberFormatter alloc] init];
                [formatter setNumberStyle:NSNumberFormatterNoStyle];
                for (NSDictionary *plugFromServer in serverPlugArray){
                    Plug *newLocalPlug=[NSEntityDescription insertNewObjectForEntityForName:@"Plug" inManagedObjectContext:context];
                    newLocalPlug.plugID = [plugFromServer valueForKey:@"id"];
                    newLocalPlug.name = [plugFromServer valueForKey:@"name"];
                    newLocalPlug.location = [plugFromServer valueForKey:@"loc"];
                    newLocalPlug.notes = [plugFromServer valueForKey:@"notes"];
                    newLocalPlug.state=[plugFromServer valueForKey:@"state"];
                }
                [document saveToURL:document.fileURL forSaveOperation:UIDocumentSaveForOverwriting completionHandler:NULL];
            }];
        }else{
            NSLog(@"PLUGFETCHER  getAllPlugs:json response=fail");        
        }
    });
}

-(void)updatePlug:(Plug*)plug{
    NSString *json = [JSONQuery queryUpdateDevice:plug.plugID 
                                             name:plug.name 
                                         location:plug.location
                                            notes:plug.notes
                                            dummy:plug.dummy 
                                            state:plug.state
                                         timezone:[NSString stringWithFormat:@"%@", plug.timeZone.utcOffset]];    
    [self.serverCommManager send:json];
}



PlugDetailTVC:

if ([[segue identifier] isEqualToString:@"savePlugDetail"]){

        //forces saving of info in field be edited when button is pushed
        [self.view.window endEditing: YES];
        [self.currentTextField endEditing:YES];
         NSLog(@"PlugDetailTVC prepareForSeque plug:%@",self.plug.plugID);
        PlugFetcher *plugFetcher= [PlugFetcher getInstance];
        [plugFetcher updatePlug:self.plug];
}

iOS5 UIManagedDocument和FetchedResultsController异常，保存更改

0 个答案: