[英]Problems with Float on core-data
The following code largely inspired by some example I found on the net seems to work fine, with the core data entity called "Contact" and the property called "address" having an attribute String, in the xcdatamodel. 下面的代码很大程度上受到我在网上发现的一些例子的启发,似乎工作得很好,核心数据实体称为“Contact”,而xcdatamodel中的属性名为“address”,属性为String。 It saves my data with no problem. 它可以毫无问题地保存我的数据。 Now my question is : how do I need to modify this code ? 现在我的问题是:我如何修改此代码? In order to make it work after I change the attribute of the property "address" from String to Float in the xcdatamodel. 在xcdatamodel中将属性“address”的属性从String更改为Float后,为了使其工作。
CoreDataTestOneAppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
NSManagedObjectContext *context = [appDelegate managedObjectContext];
NSManagedObject *newContact;
newContact = [NSEntityDescription insertNewObjectForEntityForName:@"Contacts" inManagedObjectContext:context];
[newContact setValue:address_InputField.text forKey:@"address"];
NSError *error;
[context save:&error];
要将浮点数存储在Core Data浮点属性中,请将其包装在NSNumber对象中,如下所示:
[newContact setValue:[NSNumber numberWithFloat:floatValue] forKey:@"address"];
This is a guess, but I think you will need to wrap that float in a NSNumber. 这是一个猜测,但我认为你需要将该浮动包装在NSNumber中。 numberWithFloat: numberWithFloat:
Creates and returns an NSNumber object containing a given value, treating it as a float.
+ (NSNumber *)numberWithFloat:(float)value
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