Question

嗨基于一个教程，我已经在Add New view controller中连接了Done按钮的方法。

文本字段保存回自己的控制器。该程序构建和运行。但是当您单击“完成”按钮以保存新记录时，它会引发错误。该方法似乎输入了文本 - 基于调试器中name NSString * @"jkl" 0x00007f9828d8d6b0的存在，但NS实体为nil并且崩溃。entity NSEntityDescription * nil 0x0000000000000000我已经三次检查了实体的名称和它是正确的。

谁能告诉我可能出现的问题？谢谢！

- (IBAction)save:(id)sender {
    // Helpers
    NSString *name = self.textField.text;
  [[[UIAlertView alloc] initWithTitle:@"We got data" message:name delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil] show];
    if (name && name.length) {
        // Create Entity FOLLOWING LINE IS HIGHLIGHTED AND THROWS ERROR
        NSEntityDescription *entity = [NSEntityDescription entityForName:@"TSPItem" inManagedObjectContext:self.managedObjectContext];
 //END HIGHLIGHTED ERRROR       
        // Initialize Record
        NSManagedObject *record = [[NSManagedObject alloc] initWithEntity:entity insertIntoManagedObjectContext:self.managedObjectContext];

        // Populate Record
        [record setValue:name forKey:@"name"];
        [record setValue:[NSDate date] forKey:@"createdAt"];

        // Save Record
        NSError *error = nil;

        if ([self.managedObjectContext save:&error]) {
            // Dismiss View Controller
            [self dismissViewControllerAnimated:YES completion:nil];

        } else {
            if (error) {
                NSLog(@"Unable to save record.");
                NSLog(@"%@, %@", error, error.localizedDescription);
            }

            // Show Alert View
            [[[UIAlertView alloc] initWithTitle:@"Warning" message:@"Your field could not be saved." delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil] show];
        }

    } else {
        // Show Alert View
        [[[UIAlertView alloc] initWithTitle:@"Warning" message:@"Your field needs a name." delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil] show];
    }

编辑：

以下是其中一个主题的其他内容。我在调试方面不够熟练，不知道它意味着什么：

0x10ce9de77:  leaq   0x26fa82(%rip), %r8       ; @"+entityForName: nil is not a legal NSManagedObjectContext parameter searching for entity name '%@'"
0x10ce9de7e:  jmp    0x10ce9dece               ; +[NSEntityDescription entityForName:inManagedObjectContext:] + 206
0x10ce9de80:  movq   0x2c5311(%rip), %r14      ; (void *)0x000000010dce1458: NSException
0x10ce9de87:  movq   0x2691ca(%rip), %rax      ; (void *)0x000000010dca9a20: NSInvalidArgumentException
0x10ce9de8e:  movq   (%rax), %r15
0x10ce9de91:  movq   0x2c52b8(%rip), %rcx      ; (void *)0x000000010d585e90: NSString
0x10ce9de98:  movq   0x2be8e9(%rip), %rdx      ; "stringWithFormat:"
0x10ce9de9f:  leaq   0x26fa7a(%rip), %r8       ; @"+entityForName: nil is not a legal NSPersistentStoreCoordinator for searching for entity name '%@'"
0x10ce9dea6:  jmp    0x10ce9dece               ; +[NSEntityDescription entityForName:inManagedObjectContext:] + 206
0x10ce9dea8:  movq   0x2c52e9(%rip), %r14      ; (void *)0x000000010dce1458: NSException
0x10ce9deaf:  movq   0x26919a(%rip), %rax      ; (void *)0x000000010dca9a28: NSInternalInconsistencyException
0x10ce9deb6:  movq   (%rax), %r15
0x10ce9deb9:  movq   0x2c5290(%rip), %rcx      ; (void *)0x000000010d585e90: NSString
0x10ce9dec0:  movq   0x2be8c1(%rip), %rdx      ; "stringWithFormat:"
0x10ce9dec7:  leaq   0x26fa72(%rip), %r8       ; @"+entityForName: could not locate an NSManagedObjectModel for entity name '%@'"
0x10ce9dece:  movq   0x2692eb(%rip), %r12      ; (void *)0x000000010d6e9000: objc_msgSend
0x10ce9ded5:  xorl   %eax, %eax
0x10ce9ded7:  movq   %rcx, %rdi
0x10ce9deda:  movq   %rdx, %rsi
0x10ce9dedd:  movq   %r8, %rdx
0x10ce9dee0:  movq   %rbx, %rcx
0x10ce9dee3:  callq  *%r12
0x10ce9dee6:  movq   0x2be55b(%rip), %rcx      ; "exceptionWithName:reason:userInfo:"

IOS / Xcode：NSEntityDescription无错误

0 个答案: