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iOS how solve NSCFString objectForKey:

I

ITCreative

macrumors member
Original poster
in my code there is exception:

* Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSCFString objectForKey:]: unrecognized selector sent to instance 0x6133a70'
Click to expand...

this is my code


Code: 
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
[buffer setLength:0];}

  - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
 [buffer appendData:data];}


- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    NSString *str = [[[NSString alloc] initWithData:buffer encoding:NSUTF8StringEncoding] autorelease];

    NSArray *array = [str JSONValue];

    if (!array)
        return;

    NSDateFormatter *fmt = [[[NSDateFormatter alloc] init] autorelease];
    [fmt setDateFormat:@"yyyy-MM-dd"];

    for (NSDictionary *dict in array) {
        NSLog(@"Class of eve_date = %@", [[dict objectForKey:@"eve_date"]class]);

        NSDate *d = [fmt dateFromString:[dict objectForKey:@"eve_date"]];

        NSLog(@"%@",d);
        [eventPHP addObject:[Events eventsNamed:[dict objectForKey:@"title_event"] description:[dict objectForKey:@"description"] date:d]];
    }
}

This is my data

{"event":[{"eve_date":"2011-12-24","eve_time":"1 pm","title":"Tooth Regeneration Research","decription":"Tooth Regeneration Research:Where Do we stand today?\r\n\r\nBy: Dr.Tarek H El-Bialy,phD,FRCD(c)\r\n\r\nvenue:VIP ROOM,college of Dentistry,KSU"},{"eve_date":"2011-12-21","eve_time":"8 am","title":"The First Knowledge Translation(KT)","decription":"The First Knowledge Translation(KT)symposium in saudi Arabia\r\n\r\nvenue: main Auditorium,college of medicine\r\n\r\nFor Registration and further inquiries please concat:\r\n\r\nTel:4690790\/Email:ebhc-kt@ksu.edu.sa"}]}
Click to expand...

plz help me to solve it i search to find way to solve it but didn't found result. 🙁
 
Are you sure array is an array ? Are you sure dict is a dictionary ? The exception seems to point to dict being a NSCFString, not a NSDictionary. That is why it's not responding to objectForKey: which is a selector in the NSDictionary class.

Reading through the JSON API, it states the following :

Code: 
@interface NSString (NSString_SBJsonParsing)

/**
 @brief Decodes the receiver's JSON text
 
 @return the NSDictionary or NSArray represented by the receiver, or nil on error.
 
 @see @ref json2objc
 */
- (id)JSONValue;

Maybe you want to make sure it's returning what you think it's returning, ie, an array. Look into NSObject's isKindofClass: and go from there (or use the debugger to inspect the objects being returned in your function).

Seems to me your first call to [str JSONValue] is returning an NSDictionary and your for is then looping not through an array, but through the key/value pairs of the dictionary itself, which are probably all NSString objects that do not respond to objectForKey:.
 
KnightWRX said:
Are you sure array is an array ? Are you sure dict is a dictionary ? The exception seems to point to dict being a NSCFString, not a NSDictionary. That is why it's not responding to objectForKey: which is a selector in the NSDictionary class.

Reading through the JSON API, it states the following :

Code: 
@interface NSString (NSString_SBJsonParsing)

/**
 @brief Decodes the receiver's JSON text
 
 @return the NSDictionary or NSArray represented by the receiver, or nil on error.
 
 @see @ref json2objc
 */
- (id)JSONValue;

Maybe you want to make sure it's returning what you think it's returning, ie, an array. Look into NSObject's isKindofClass: and go from there (or use the debugger to inspect the objects being returned in your function).

Seems to me your first call to [str JSONValue] is returning an NSDictionary and your for is then looping not through an array, but through the key/value pairs of the dictionary itself, which are probably all NSString objects that do not respond to objectForKey:.
Click to expand...


I try print " str " & " array to make sure receive data this is result:


str :

2011-12-22 01:35:52.506 iKSU[4318:207] str: {"event":[{"eve_date":"2011-12-24","eve_time":"1 pm","title":"Tooth Regeneration Research","decription":"Tooth Regeneration Research:Where Do we stand today?\r\n\r\nBy: Dr.Tarek H El-Bialy,phD,FRCD(c)\r\n\r\nvenue:VIP ROOM,college of Dentistry,KSU"},{"eve_date":"2011-12-21","eve_time":"8 am","title":"The First Knowledge Translation(KT)","decription":"The First Knowledge Translation(KT)symposium in saudi Arabia\r\n\r\nvenue: main Auditorium,college of medicine\r\n\r\nFor Registration and further inquiries please concat:\r\n\r\nTel:4690790\/Email:ebhc-kt@ksu.edu.sa"}]}
Click to expand...

then print array :

2011-12-22 01:35:52.507 iKSU[4318:207] Array: {
event = (
{
decription = "Tooth Regeneration Research:Where Do we stand today?
\n
\nBy: Dr.Tarek H El-Bialy,phD,FRCD(c)
\n
\nvenue:VIP ROOM,college of Dentistry,KSU";
"eve_date" = "2011-12-24";
"eve_time" = "1 pm";
title = "Tooth Regeneration Research";
},
{
decription = "The First Knowledge Translation(KT)symposium in saudi Arabia
\n
\nvenue: main Auditorium,college of medicine
\n
\nFor Registration and further inquiries please concat:
\n
\nTel:4690790/Email:ebhc-kt@ksu.edu.sa";
"eve_date" = "2011-12-21";
"eve_time" = "8 am";
title = "The First Knowledge Translation(KT)";
}
);
}
Click to expand...

the exception happen


2011-12-22 01:35:52.506 iKSU[4318:207] str: {"event":[{"eve_date":"2011-12-24","eve_time":"1 pm","title":"Tooth Regeneration Research","decription":"Tooth Regeneration Research:Where Do we stand today?\r\n\r\nBy: Dr.Tarek H El-Bialy,phD,FRCD(c)\r\n\r\nvenue:VIP ROOM,college of Dentistry,KSU"},{"eve_date":"2011-12-21","eve_time":"8 am","title":"The First Knowledge Translation(KT)","decription":"The First Knowledge Translation(KT)symposium in saudi Arabia\r\n\r\nvenue: main Auditorium,college of medicine\r\n\r\nFor Registration and further inquiries please concat:\r\n\r\nTel:4690790\/Email:ebhc-kt@ksu.edu.sa"}]}
2011-12-22 01:35:52.507 iKSU[4318:207] Array: {
event = (
{
decription = "Tooth Regeneration Research:Where Do we stand today?
\n
\nBy: Dr.Tarek H El-Bialy,phD,FRCD(c)
\n
\nvenue:VIP ROOM,college of Dentistry,KSU";
"eve_date" = "2011-12-24";
"eve_time" = "1 pm";
title = "Tooth Regeneration Research";
},
{
decription = "The First Knowledge Translation(KT)symposium in saudi Arabia
\n
\nvenue: main Auditorium,college of medicine
\n
\nFor Registration and further inquiries please concat:
\n
\nTel:4690790/Email:ebhc-kt@ksu.edu.sa";
"eve_date" = "2011-12-21";
"eve_time" = "8 am";
title = "The First Knowledge Translation(KT)";
}
);
}
2011-12-22 01:35:52.508 iKSU[4318:207] -[NSCFString objectForKey:]: unrecognized selector sent to instance 0x64180d0
2011-12-22 01:35:52.511 iKSU[4318:207] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSCFString objectForKey:]: unrecognized selector sent to instance 0x64180d0'
Click to expand...
 
You need to better understand your JSON structures. { is the start of an object, i.e. a dictionary with these tools. [ is the start of an array. Your string starts with a dictionary.
 
KnightWRX said:
Are you sure array is an array ? Are you sure dict is a dictionary ? The exception seems to point to dict being a NSCFString, not a NSDictionary. That is why it's not responding to objectForKey: which is a selector in the NSDictionary class.

Reading through the JSON API, it states the following :

Code: 
@interface NSString (NSString_SBJsonParsing)

/**
 @brief Decodes the receiver's JSON text
 
 @return the NSDictionary or NSArray represented by the receiver, or nil on error.
 
 @see @ref json2objc
 */
- (id)JSONValue;

Maybe you want to make sure it's returning what you think it's returning, ie, an array. Look into NSObject's isKindofClass: and go from there (or use the debugger to inspect the objects being returned in your function).

Seems to me your first call to [str JSONValue] is returning an NSDictionary and your for is then looping not through an array, but through the key/value pairs of the dictionary itself, which are probably all NSString objects that do not respond to objectForKey:.
Click to expand...



I try use isKindOfClass

Code: 
NSDictionary *dict = [str JSONValue];
	
	id myObject = [dict valueForKeyPath:@"event"];
	if ([myObject isKindOfClass:[NSDictionary class]]) {
	NSArray *array = [NSArray arrayWithObject:myObject];
		NSLog(@"YES %@",array);
	} else {
	NSArray *array = myObject;
		NSLog(@"NO %@",array);

	}

it is print NO




dejo said:
You need to better understand your JSON structures. { is the start of an object, i.e. a dictionary with these tools. [ is the start of an array. Your string starts with a dictionary.
Click to expand...


ok thanx 😱, i try solve it.
 
ITCreative said:
I try use isKindOfClass

Code: 
NSDictionary *dict = [str JSONValue];
	
	id myObject = [dict valueForKeyPath:@"event"];
	if ([myObject isKindOfClass:[NSDictionary class]]) {
	NSArray *array = [NSArray arrayWithObject:myObject];
		NSLog(@"YES %@",array);
	} else {
	NSArray *array = myObject;
		NSLog(@"NO %@",array);

	}

it is print NO
Click to expand...

What is [dict valueForKeyPath😡"event"]; and what type of object does that return ? You changed the code completely, you weren't using this valueForKeyPath: selector before. valueForKeyPath: can return more than 1 object and thus it could return either a Dictionary, an Array or something else entirely seeing how it returns an object. Are you sure your call with the string @"event" is going to return what you think it's going to return ?

Did you try simply implementing isKindOfClass in your original code ? Did you look at the object types returned through the debugger ? I think before changing anything else, you should just fix your broken initial code with our suggestions, then look at making changes/modifications.
 
I change my code to :


Code: 
NSString *str = [[[NSString alloc] initWithData:buffer encoding:NSUTF8StringEncoding] autorelease];
	NSLog(@"str: %@",str);
	
	NSDictionary *dict = [str JSONValue];
	
	NSDateFormatter *fmt = [[[NSDateFormatter alloc] init] autorelease];
	[fmt setDateFormat:@"yyyy-MM-dd"];
	
 	
		
	NSArray *array = [[dict objectForKey:@"event"] retain];
		
	NSLog(@"Array: %@",array);
	
		
	
	for (NSDictionary *tempdict in array)
	{
		NSDate *d = [fmt dateFromString:[tempdict objectForKey:@"eve_date"]];
		NSLog(@"Date %@",d);
		NSLog(@"Date of event %@",[tempdict objectForKey:@"eve_date"]);

		NSLog(@"This is title_event %@",[tempdict objectForKey:@"title"]);
		NSLog (@"Time of event %@", [tempdict objectForKey:@"eve_time"]);
		NSLog(@"This is description %@",[tempdict objectForKey:@"description"]);
		
	[eventPHP addObject:[Events eventsNamed:[tempdict objectForKey:@"title"] description:[tempdict objectForKey:@"description"] date:[tempdict objectForKey:@"eve_date"]]];
		
		
		
		
	}


it work fine its print every thing but in this line :

Code: 
[eventPHP addObject:[Events eventsNamed:[tempdict objectForKey:@"title"] description:[tempdict objectForKey:@"description"] date:[tempdict objectForKey:@"eve_date"]]];

there is exception

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSDate length]: unrecognized selector sent to instance 0x6456a80'
Click to expand...

how solve this exception ?
 
ITCreative said:
Code: 
[eventPHP addObject:[Events eventsNamed:[tempdict objectForKey:@"title"] description:[tempdict objectForKey:@"description"] date:[tempdict objectForKey:@"eve_date"]]];

there is exception



how solve this exception ?
Click to expand...

You'll need to help us a bit. What is Events ? What is the eventsNamed method's argument types ?

Finally, are you sure [tempdict objectForKey: @"eve_date"] returns an NSDate object ? Your eventsNamed method probably wants an NSDate for the date: argument but your dictionary contains something else for the key eve_date.
 
KnightWRX said:
You'll need to help us a bit. What is Events ? What is the eventsNamed method's argument types ?
Click to expand...


Code: 
+ (Events*)eventsNamed:(NSString *)atitle description:(NSString *)adescription date:(NSDate *)aDate
{

	return [[[Events alloc] initWithName:atitle description:adescription date:aDate] autorelease];
}


Finally, are you sure [tempdict objectForKey: @"eve_date"] returns an NSDate object ? Your eventsNamed method probably wants an NSDate for the date: argument but your dictionary contains something else for the key eve_date.
Click to expand...


ya i test [tempdict objectForKey: @"eve_date"] it is print date 😕
 
ITCreative said:
Code: 
+ (Events*)eventsNamed:(NSString *)atitle description:(NSString *)adescription date:(NSDate *)aDate
{

	return [[[Events alloc] initWithName:atitle description:adescription date:aDate] autorelease];
}





ya i test [tempdict objectForKey: @"eve_date"] it is print date 😕
Click to expand...

Ok, looking further into it, NSDate does not have a length method or property. What is Events and what does its initWithName procedure do with the date ? If it alls [aDate length] at any point, that is what is causing your exception.

It's basically the same error you got initially in this post, you're calling a method/property on a class that doesn't have this method or property.

You probably have a warning for it, Xcode gives me one here :

Code: 
main.m: warning: Semantic Issue: 'NSDate' may not respond to 'length'
 
KnightWRX said:
Ok, looking further into it, NSDate does not have a length method or property. What is Events and what does its initWithName procedure do with the date ? If it alls [aDate length] at any point, that is what is causing your exception.

It's basically the same error you got initially in this post, you're calling a method/property on a class that doesn't have this method or property.

You probably have a warning for it, Xcode gives me one here :

Code: 
main.m: warning: Semantic Issue: 'NSDate' may not respond to 'length'
Click to expand...

Events its class contain some property

and this is initWithName

Code: 
- (id)initWithName:(NSString *)atitle description:(NSString *)adescription date:(NSDate *)aDate
{
	

	if ((self = [super init])) {
		title = [atitle copy];
		description = [adescription copy];
		date = [aDate retain];
	}
	return self;
	
}
 
ITCreative said:
Events its class contain some property

and this is initWithName

Code: 
- (id)initWithName:(NSString *)atitle description:(NSString *)adescription date:(NSDate *)aDate
{
	

	if ((self = [super init])) {
		title = [atitle copy];
		description = [adescription copy];
		date = [aDate retain];
	}
	return self;
	
}
Click to expand...

Edit, NVM, look at this :

Code: 
NSDate *d = [fmt dateFromString:[tempdict objectForKey:@"eve_date"]];
...
[eventPHP addObject:[Events eventsNamed:[tempdict objectForKey:@"title"] description:[tempdict objectForKey:@"description"] date:[tempdict objectForKey:@"eve_date"]]];

In your first line, why are you assuming [tempdict objectForKey😡"eve_date"] to return a NSString, but then you told me it returns an NSDate for the 2nd line ?

Something is not right there.
 
Last edited:
KnightWRX said:
Edit, NVM, look at this :

Code: 
NSDate *d = [fmt dateFromString:[tempdict objectForKey:@"eve_date"]];
...
[eventPHP addObject:[Events eventsNamed:[tempdict objectForKey:@"title"] description:[tempdict objectForKey:@"description"] date:[tempdict objectForKey:@"eve_date"]]];

In your first line, why are you assuming [tempdict objectForKey😡"eve_date"] to return a NSString, but then you told me it returns an NSDate for the 2nd line ?

Something is not right there.
Click to expand...


ya i think in [ description ] because in my sql its text type but i xcode it is NSString. Is this wrong ?
 
ITCreative said:
ya i think in [ description ] because in my sql its text type but i xcode it is NSString. Is this wrong ?
Click to expand...

No, it's ok, but you're sending an NSString as an argument to something that wants an NSDate. That's a bug.

As for your other selector exception, did you step through the code (using Step Into, not Step Over) to see what actual line triggers the exception ?
 
KnightWRX said:
No, it's ok, but you're sending an NSString as an argument to something that wants an NSDate. That's a bug.

As for your other selector exception, did you step through the code (using Step Into, not Step Over) to see what actual line triggers the exception ?
Click to expand...

i use NSLog :

Code: 
- (id)initWithName:(NSString *)atitle description:(NSString *)adescription date:(NSDate *)aDate
{
	

if ((self = [super init])) {
		title = [atitle copy];
	NSLog(@"initWithName title = %@",title);
		description = [adescription copy];
	NSLog(@"initWithName description = %@",description);

		date = [aDate retain];
	NSLog(@"initWithName date = %@",date);

	//date = aDate;
	}
	return self;
	NSLog(@"I am here in initWithName");
	
}

all this property printed but

NSLog(@"I am here in initWithName");

dosen't printed 😕
 
What do you understand about the return statement and how it affects execution flow?
 
dejo said:
What do you understand about the return statement and how it affects execution flow?
Click to expand...

because in my project there is many class one of them class [ Events] so
I'm not sure from "self = [super init]" 😕

i try self = [Events init];

but still exception exists
 
Code: 
	self = [super initWithNibName:@"Events" bundle:nil];

	
	if (self != nil)
	{
		title = [atitle copy];
		NSLog(@"initWithName title = %@",title);
		description = [adescription copy];
		NSLog(@"initWithName description = %@",description);
		
		date = [aDate retain];
		NSLog(@"initWithName date = %@",date);
		
		
	}
	NSLog(@" self %@",self);
	NSLog(@"I am here in initWithName before return");

	return self;
	NSLog(@"I am here in initWithName");
	
}

when print this line this :

NSLog(@" self %@",self);


self *nil description*
Click to expand...

why self print value of description 😕
 
Thank very much for all 😱

i solve my problem now just try solve

Code: 
- (NSArray *)eventsFrom:(NSDate *)fromDate to:(NSDate *)toDate
{
	NSMutableArray *matches = [NSMutableArray array];
	for (Events *event in eventPHP)
	if (IsDateBetweenInclusive(event.date, fromDate, toDate))

			[matches addObject:event];
	NSLog(@"matches %@",matches);
	
	return matches;
}


static BOOL IsDateBetweenInclusive(NSDate *date, NSDate *begin, NSDate *end)
{
	return [date compare:begin] != NSOrderedAscending && [date compare:end] != NSOrderedDescending;
}

it is exception : bad execution



Thankxxxxxx for allll 😱
 
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