Re: Core Data Form
Jon,
First off, unless you're doing something special you don't need to
create custom classes for each entity. If your managed object really
is just slinging strings, leave the class as NSManagedObject and
create a new entity with:
NSManagedObject *hostObj = [NSEntityDescription
insertNewObjectForEntityForName:@Host inManagedObjectContext:[[NSApp
delegate] managedObjectContext]];
then set the values on that object with:
[hostObj setValue: hostString forKey:@hostStringKey];
etc...
Second, your +(id)addHostFromPanel: method is a class method yet
you're asking for [self managedObjectContext], which is an instance
method. Basically, you don't have a properly initialized managed
object at the time you asked for the context it's in.
If you're set on sticking with the class method, you could do
something like the following:
// Written in TextEdit, forgive the formatting
+(id)addHostFromPanel:(NSString *)hostPanel name:(NSString *)hostName
ipAddress:(NSString *)ipAddress group:(NSString *)group
inManagedObjectContext:(NSManangedObjectContext *)objContext
{
self = [super insertNewObjectForEntityForName:@Host
inManagedObjectContext:objContext];
if( self != nil )
{
[self setValue:hostName forKey:@hostNameKey];
etc...
}
return( self );
}
I'm not much of a CoreData ninja but I hope that helps.
Jim
On Thu, Sep 4, 2008 at 6:01 AM, Jon Buys [EMAIL PROTECTED] wrote:
Hello,
I have a problem with my app that is most likely very simple for someone
with experience. I have a core data based application that I would like to
be able to add objects to via a sheet that drops down when the user clicks
the + button (or presses Command-N). On the sheet are two NSTextField and
one NSPopUpButton, an add button and a cancel button. From my AppController
class I can get the values as strings that are entered into the sheet here:
- (IBAction)endAddHostSheet:(id)sender
{
NSString *hostString = [hostNameTextField stringValue];
if ([hostString length] == 0)
{
return;
}
NSLog(@the host name is %@, hostString);
NSString *ipAddressString = [ipAddressTextField stringValue];
if ([ipAddressString length] == 0)
{
return;
}
NSLog(@the ip address is %@, ipAddressString);
NSString *selectedGroupString = [groupsPopUpButton
titleOfSelectedItem];
NSLog(@the selected Group is %@, selectedGroupString);
// Do stuff to add to core data here...
[NSApp endSheet:addHostSheet];
//Goodbye, sheet
[addHostSheet orderOut:sender];
}
But my question is, how can I add these strings to core data?
My core data setup is very simple. I have three entities (one which I'm not
yet using) named Host, Group, and ContactGroup. Host has attributes
hostName, ipAddress, and a to-one relationship named group. Group has an
attribute groupName, and a to-many relationship named hosts.
I've defined classes for the Entities, like this:
#import Cocoa/Cocoa.h
@class ContactGroup;
@class Group;
@interface Host : NSManagedObject {
}
@property (readwrite, retain) ContactGroup *contactGroup;
@property (readwrite, retain) Group *group;
@property (readwrite, copy) NSString *hostName, *ipAddress, *CPU, *RAM,
*hardDrive;
+(id)addHostFromPanel:(NSString *)newHostPanel withName:(NSString
*)newHostName andIpAddress:(NSString *)newIpAddress inGroup:(NSString
*)newGroup;
@end
I've was trying to add the hosts with the addHostFromPanel method defined
above (with a + instead of a -), and implemented like this:
+(id)addHostFromPanel:(NSString *)newHostPanel withName:(NSString
*)newHostName andIpAddress:(NSString *)newIpAddress inGroup:(NSString
*)newGroup
{
// Debug stuff
NSLog(@host name passed over is is %@, newHostName);
NSLog(@ip address passed over is is %@, newIpAddress);
NSLog(@the group passed over is %@, newGroup);
// Here we go!
Host *host = [NSEntityDescription
insertNewObjectForEntityForName:@Host inManagedObjectContext:[self
managedObjectContext]];
host.hostName = newHostName;
host.ipAddress = newIpAddress;
host.group = newGroup;
return host;
}
But, when I try to call this method from my AppController to add the strings
to core data, I get an error (as well as a compile warning) that Host can't
find it's managedObjectContext.
I'm very new to Cocoa (obviously), and right now I'm very confused. I'm
sure I'm missing something very basic here, but I've been stuck on this for
a couple of weeks now.
Thanks in advance for any advice.
Jon
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Re: Core Data Form
NSManagedObject *hostObj = [NSEntityDescription
insertNewObjectForEntityForName:@Host inManagedObjectContext:[[NSApp
delegate] managedObjectContext]];
Ahhh... there's what I was missing: the [NSApp delegate] part of
declaring a new entity. I'm not at my Mac right now, but I'll give
that a try tonight.
then set the values on that object with:
[hostObj setValue: hostString forKey:@hostStringKey];
etc...
Yep, that's what I've been doing, but I've been chasing the
ManagedObjectContext around. I'm thinking that the example above will
fix that.
Second, your +(id)addHostFromPanel: method is a class method yet
you're asking for [self managedObjectContext], which is an instance
method. Basically, you don't have a properly initialized managed
object at the time you asked for the context it's in.
Yea, I figured that wasn't right.
If you're set on sticking with the class method, you could do
something like the following:
// Written in TextEdit, forgive the formatting
+(id)addHostFromPanel:(NSString *)hostPanel name:(NSString *)hostName
ipAddress:(NSString *)ipAddress group:(NSString *)group
inManagedObjectContext:(NSManangedObjectContext *)objContext
{
self = [super insertNewObjectForEntityForName:@Host
inManagedObjectContext:objContext];
if( self != nil )
{
[self setValue:hostName forKey:@hostNameKey];
etc...
}
return( self );
}
I'm not much of a CoreData ninja but I hope that helps.
Jim
Awesome, thanks! I think this will help out a lot.
Jon
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Core Data Form
Hello,
I have a problem with my app that is most likely very simple for
someone with experience. I have a core data based application that I
would like to be able to add objects to via a sheet that drops down
when the user clicks the + button (or presses Command-N). On the
sheet are two NSTextField and one NSPopUpButton, an add button and a
cancel button. From my AppController class I can get the values as
strings that are entered into the sheet here:
- (IBAction)endAddHostSheet:(id)sender
{
NSString *hostString = [hostNameTextField stringValue];
if ([hostString length] == 0)
{
return;
}
NSLog(@the host name is %@, hostString);
NSString *ipAddressString = [ipAddressTextField stringValue];
if ([ipAddressString length] == 0)
{
return;
}
NSLog(@the ip address is %@, ipAddressString);
NSString *selectedGroupString = [groupsPopUpButton
titleOfSelectedItem];
NSLog(@the selected Group is %@, selectedGroupString);
// Do stuff to add to core data here...
[NSApp endSheet:addHostSheet];
//Goodbye, sheet
[addHostSheet orderOut:sender];
}
But my question is, how can I add these strings to core data?
My core data setup is very simple. I have three entities (one which
I'm not yet using) named Host, Group, and ContactGroup. Host has
attributes hostName, ipAddress, and a to-one relationship named
group. Group has an attribute groupName, and a to-many relationship
named hosts.
I've defined classes for the Entities, like this:
#import Cocoa/Cocoa.h
@class ContactGroup;
@class Group;
@interface Host : NSManagedObject {
}
@property (readwrite, retain) ContactGroup *contactGroup;
@property (readwrite, retain) Group *group;
@property (readwrite, copy) NSString *hostName, *ipAddress, *CPU,
*RAM, *hardDrive;
+(id)addHostFromPanel:(NSString *)newHostPanel withName:(NSString
*)newHostName andIpAddress:(NSString *)newIpAddress inGroup:(NSString
*)newGroup;
@end
I've was trying to add the hosts with the addHostFromPanel method
defined above (with a + instead of a -), and implemented like this:
+(id)addHostFromPanel:(NSString *)newHostPanel withName:(NSString
*)newHostName andIpAddress:(NSString *)newIpAddress inGroup:(NSString
*)newGroup
{
// Debug stuff
NSLog(@host name passed over is is %@, newHostName);
NSLog(@ip address passed over is is %@, newIpAddress);
NSLog(@the group passed over is %@, newGroup);
// Here we go!
Host *host = [NSEntityDescription
insertNewObjectForEntityForName:@Host inManagedObjectContext:[self
managedObjectContext]];
host.hostName = newHostName;
host.ipAddress = newIpAddress;
host.group = newGroup;
return host;
}
But, when I try to call this method from my AppController to add the
strings to core data, I get an error (as well as a compile warning)
that Host can't find it's managedObjectContext.
I'm very new to Cocoa (obviously), and right now I'm very confused.
I'm sure I'm missing something very basic here, but I've been stuck on
this for a couple of weeks now.
Thanks in advance for any advice.
Jon
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