Question

我尝试使用块向实体添加新值，如下所示，

[context performBlockAndWait:^{

                     // remove all rows
                     NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"PendingShipmentDetails"];
                     NSError *error;
                     NSArray * pendingShipments = [context executeFetchRequest:request error:&error];
                     for (NSManagedObject *pendingShipment in pendingShipments) {
                         [context deleteObject: pendingShipment];
                     }

                     // add new row(s)

                     NSManagedObject *pendingShipment = [NSEntityDescription insertNewObjectForEntityForName:@"PendingShipmentDetails" inManagedObjectContext:context];

                     // TODO: set values here (e.g. [pendingShipment setValue:...)
                     [pendingShipment setValue:shipmentNumber forKey:@"shipmentno"];
                     [pendingShipment setValue:proformaInvoiceNumber forKey:@"proforma_invoice_no"];
                     [pendingShipment setValue:proformaInvoiceDate forKey:@"proforma_invoice_date"];
                     [pendingShipment setValue:invoiceNo forKey:@"invoice_no"];
                     [pendingShipment setValue:invoiceDate forKey:@"invoice_date"];
                     [pendingShipment setValue:plannedShipmentDates forKey:@"planned_shipment_date"];
                     [pendingShipment setValue:address forKey:@"point_of_contact"];
                     [pendingShipment setValue:address forKey:@"empid"];
                     [pendingShipment setValue:name forKey:@"products"];
                     [pendingShipment setValue:qty forKey:@"quantity"];
                     [pendingShipment setValue:rte forKey:@"rate"];
                     [pendingShipment setValue:amt forKey:@"amount"];
                     [pendingShipment setValue:img forKey:@"product_image"];
                     [pendingShipment setValue:pendingStatus forKey:@"status"];

                     // save MOC
                     if ([context hasChanges]) {
                         (void)[context save:&error];
                     }
                 }];

首先，我正在尝试删除所有现有行其次，我用新记录填充它。

问题在于，只插入了最后一个值。我怎样才能纠正它？

更新：

-(void)pendingShipmentDetails
{
    keyChain = [[KeyChainItemWrapper alloc] initWithIdentifier:@"LoginController" accessGroup:nil];
    NSString *username = [keyChain objectForKey:(__bridge id)(kSecAttrLabel)];

    NSString *bodyString = [NSString stringWithFormat:@"{\"method\":\"pending_shipment_details\",\"data\":{\"username\":\"%@\"}}",username];

    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"URL"]];
    NSData *postData = [bodyString dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
    [request setHTTPBody:postData];
    [request setHTTPMethod:@"POST"];
    NSString *postLength = [NSString stringWithFormat:@"%lu", (unsigned long)[postData length]];
    [request setValue:postLength forHTTPHeaderField:@"Content-Length"];

    NSOperationQueue *queue = [[NSOperationQueue alloc] init];

    [NSURLConnection sendAsynchronousRequest:request queue:queue completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError)
     {
         if ([data length] > 0 && connectionError == nil)
         {
             [self receivedPendingShipmentDetailsData:data];
             NSString* pendingResponse = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
             NSData *jsonData = [pendingResponse dataUsingEncoding:NSUTF8StringEncoding];
             NSDictionary *jsonDic = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingAllowFragments error:nil];
             NSDictionary *valueDict = [jsonDic objectForKey:@"value"];

             NSArray *details = [valueDict objectForKey:@"details"];

             NSMutableArray* arrayList = [[NSMutableArray alloc] init];

             for (NSDictionary *response in details) {
                 NSString *invoiceNo = [response valueForKey:@"invoice_no"];
                 NSString *shipmentNumber = [response valueForKey:@"shipment_no"];
                 NSString *invoiceDate = [response valueForKey:@"invoice_date"];
                 NSString *proformaInvoiceNumber = [response valueForKey:@"proforma_invoice_no"];
                 NSString *proformaInvoiceDate = [response valueForKey:@"proforma_invoice_date"];
                 NSString *plannedShipmentDates = [response valueForKey:@"planned_shipment_dates"];
                 NSString *pointOfContact =[[response objectForKey:@"point_of_contact"] valueForKey:@"empid"];
                 NSString *pendingStatus = [response valueForKey:@"status"];
                 NSDictionary *productName = [response valueForKey:@"products"];
                 NSDictionary *quantity = [response valueForKey:@"quantity"];
                 NSDictionary *rate = [response valueForKey:@"rate"];
                 NSDictionary *amount = [response valueForKey:@"amount"];
                 NSDictionary *productImages = [response valueForKey:@"product_image"];
                 NSDictionary *point_of_contact = [response valueForKey:@"point_of_contact"];

                 NSString *qty;
                 NSString *rte;
                 NSString *img;
                 NSString *address;
                 NSString *name;
                 NSString *amt;

                 for (int i = 0; i < [productName count]; i++) {
                     //  NSLog(@"product name %@",[productName valueForKey:[NSString stringWithFormat:@"%d",i ]]);
                     name = [productName valueForKey:[NSString stringWithFormat:@"%d",i ]];
                 }

                 for (int i = 0; i < [quantity count]; i++) {
                     //  NSLog(@"quantity %@",[quantity valueForKey:[NSString stringWithFormat:@"%d",i ]]);
                     qty = [quantity valueForKey:[NSString stringWithFormat:@"%d",i ]];
                 }

                 for (int i = 0; i < [rate count]; i++) {
                     //  NSLog(@"rate %@",[rate valueForKey:[NSString stringWithFormat:@"%d",i ]]);
                     rte = [rate valueForKey:[NSString stringWithFormat:@"%d",i ]];
                 }

                 for (int i = 0; i < [amount count]; i++) {
                     // NSLog(@"amount %@",[amount valueForKey:[NSString stringWithFormat:@"%d",i ]]);
                     amt = [amount valueForKey:[NSString stringWithFormat:@"%d",i ]];
                 }


                 for (int i = 0; i < [productImages count]; i++) {
                     // NSLog(@"product image %@",[productImages valueForKey:[NSString stringWithFormat:@"%d",i ]]);
                     img = [productImages valueForKey:[NSString stringWithFormat:@"%d",i ]];
                 }

                 for (int i = 0; i < [point_of_contact count]; i++) {
                     //  NSLog(@"pt of ct %@",[point_of_contact valueForKey:[NSString stringWithFormat:@"empid" ]]);
                     address = [point_of_contact valueForKey:[NSString stringWithFormat:@"empid" ]];
                 }


                 NSManagedObjectContext *context = [self managedObjectContext];

                 // remove all rows
                 NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"PendingShipmentDetails"];
                 NSError *error;
                 NSArray * pendingShipments = [context executeFetchRequest:request error:&error];


                 [context performBlockAndWait:^{


                     // add new row(s)
                     NSLog(@"else block");
                     NSManagedObject *pendingShipment = [NSEntityDescription insertNewObjectForEntityForName:@"PendingShipmentDetails" inManagedObjectContext:context];
                     NSError *error;

                     for (NSManagedObject *pendingShipment in pendingShipments) {
                         [context deleteObject: pendingShipment];

                     }
                     // TODO: set values here (e.g. [pendingShipment setValue:...)
                     [pendingShipment setValue:shipmentNumber forKey:@"shipmentno"];
                     [pendingShipment setValue:proformaInvoiceNumber forKey:@"proforma_invoice_no"];
                     [pendingShipment setValue:proformaInvoiceDate forKey:@"proforma_invoice_date"];
                     [pendingShipment setValue:invoiceNo forKey:@"invoice_no"];
                     [pendingShipment setValue:invoiceDate forKey:@"invoice_date"];
                     [pendingShipment setValue:plannedShipmentDates forKey:@"planned_shipment_date"];
                     [pendingShipment setValue:address forKey:@"point_of_contact"];
                     [pendingShipment setValue:address forKey:@"empid"];
                     [pendingShipment setValue:name forKey:@"products"];
                     [pendingShipment setValue:qty forKey:@"quantity"];
                     [pendingShipment setValue:rte forKey:@"rate"];
                     [pendingShipment setValue:amt forKey:@"amount"];
                     [pendingShipment setValue:img forKey:@"product_image"];
                     [pendingShipment setValue:pendingStatus forKey:@"status"];

                     // save MOC
                     if ([context hasChanges]) {
                         (void)[context save:&error];
                     }
                 }];

             }
         }

         else if ([data length] == 0 && connectionError == nil)
         {
             [self emptyReply];
         }
         else if (connectionError != nil && connectionError.code == NSURLErrorTimedOut)
         {
             [self timedOut];
         }
         else if (connectionError != nil)
         {
             [self downloadError:connectionError];
         }
     }];

}

Answer 1

您显示的代码不会循环显示新值 - 因此只能插入一个值。

如果您在循环显示新数据时多次调用您显示的代码，那么首先它会删除所有内容 - 所以无论哪种方式，您最终只会输入一个条目。

如果您正在实施第二种方法，则需要拆分删除块，并在执行新数据之前执行一次。

Answer 2

如果您打算在每次新的数据提取时删除之前提取的所有对象。然后，您应首先通过为该实体调用NSFetchRequest来删除所有持久化对象，之后使用for-in循环添加值。

您也可以使用NSBatchDeleteRequest。

//某种方法或IBAction来刷新数据 //首先删除所有旧的。

-(void) deleteStoredData
{

     NSManagedObjectContext *context = [self managedObjectContext];
 [context performBlock:^{
                 // remove all rows
                 NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"PendingShipmentDetails"];
                 NSError *error;
                 NSArray * pendingShipments = [context executeFetchRequest:request error:&error];
 for (NSManagedObject *pendingShipment in pendingShipments) {
     [context deleteObject: pendingShipment];
    }
}];

[self pendingShipmentDetails];
}

现在您的pendingShipmentDetails将是相同的，但删除对象。

-(void) pendingShipmentDetails{
// do saving using loop 
}

只在Coredata中插入了最后一个值

2 个答案: