// Configure the cell.
cell.textLabel.text = [[self.drinks objectAtIndex:indexPath.row] objectForKey:#"Name"];
return cell;
The above code is generating this exception. What could be causing this and how can I fix it?
My Understand from Your question
You have array of drinks like
Drink *d1 = [[Drink alloc] init]
d1.name = #"Drink1";
d1.price = [NSNumber numberWithFloat:25.0];
Drink *d2 = [[Drink alloc] init]
d2.name = #"Drink2";
d2.price = [NSNumber numberWithFloat:35.0];
OR
NSArray *values1 = [NSArray arrayWithObjects:#"Drink1",[NSNumber numberWithFloat:25.0], nil];
NSArray *keys1 = [NSArray arrayWithObjects:#"Name",#"price", nil];
NSDictionary *d1 = [[NSDictionary alloc] initWithObjects:values1 forKeys:keys1];
NSArray *values2 = [NSArray arrayWithObjects:#"Drink2",[NSNumber numberWithFloat:55.0], nil];
NSArray *keys2 = [NSArray arrayWithObjects:#"Name",#"price", nil];
NSDictionary *d2 = [[NSDictionary alloc] initWithObjects:values1 forKeys:keys1];
self.drinks = [NSArray arrayWithObjects:d1,d2, nil];
[d1 release];
[d2 release];
From the above case
cell.textLabel.text = [[self.drinks objectAtIndex:indexPath.row] objectForKey:#"Name"];
the above statement is correct
You are getting exception means, You are inserting the objects into drinks array, that supports Key Value Pairs data and that is String Data.
I hope you are having like this
self.drinks = [NSArray arrayWithObjects:#"Drink1",#"Drink2", nil];
In this above case you have to go with
cell.textLabel.text = [self.drinks objectAtIndex:indexPath.row];
first try to determine what object is self.drinks,
then you can go finer depending if is an array with dictionaries?
do a log
[self.drinks objectAtIndex:0]
what do you see?
Related
simple question, I need to structure data in the following format:
UserID:
1 {
Name = Bob
Surname = Hope
}
2 {
...
I can used an NSMutableDictionary to add a single layer with keys, but I am unable to create a child associate with a certain key.
I have tried creating a mutable dictionary and assigning that to a key:
NSMutableDictionary *dic = [[NSMutableDictionary alloc] init];
NSArray *keys = [[NSArray alloc] initWithObjects:#"Name", #"Surname", nil];
NSArray *details = [[NSArray alloc] initWithObjects:#"Bob",#"Hope", nil];
NSDictionary *person = [[NSMutableDictionary alloc] initWithObjects:details forKeys:keys];
[dic setValue:#"1" forKey:#"id"];
[[dic objectForKey:#"id"] setDictionary: person];
I think it is better to use an array of dictionaries, each dictionary representing a user.
NSMutableArray *users= [[NSMutableArray alloc] init];
NSArray *keys = [[NSArray alloc] initWithObjects:#"Name", #"Surname", nil];
NSArray *details = [[NSArray alloc] initWithObjects:#"Bob",#"Hope", nil];
NSDictionary *person = [[NSMutableDictionary alloc] initWithObjects:details forKeys:keys];
[users addObject:person];
u can also set the objects for dictionary in this way
[dic setObject:person forKey:#"id"];
Ok, so the issue is coming from trying to pull data from a sqlite DB and place it in an array for a scroll view display. Im using FM Database library to connect to sql database
The code is as follows:
NSMutableArray *data = [[NSMutableArray alloc] init];
FMResultSet *result = [[[StorageTank sharedStorageTank] DB]
executeQuery:#"SELECT * FROM table"];
while([result next])
{
NSArray *values = [[NSArray alloc] initWithObjects:
[[NSNumber alloc] initWithInt:[result intForColumn:#"id"]],
[[NSNumber alloc] initWithInt:[result intForColumn:#"count"]],
[[NSNumber alloc] initWithInt:[result intForColumn:#"required"]],
[result stringForColumn:#"image_portrait"],
[result stringForColumn:#"image_landscape"],
[[NSNumber alloc] initWithInt:[result intForColumn:#"end_date"]],
[[NSNumber alloc] initWithInt:[result intForColumn:#"active"]],
[result stringForColumn:#"merchant"], nil];
NSLog(#"%#", values);
NSArray *keys = [[NSArray alloc] initWithObjects: #"id",#"count",#"required",
#"image_portrait",#"image_landscape",
#"end_date",#"active",#"merchant",nil];
NSLog(#"%#", keys);
NSDictionary *row = [[NSDictionary alloc] initWithObjects: values forKeys: keys];
[data addObject: row];
}
NSArray *resultArray = [[NSArray alloc] init];
resultArray = data;
So, obviously from the code i've tested to make sure the values count is equal to the keys count... yet Im still getting this error:
"Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSPlaceholderDictionary initWithObjects:forKeys:]: number of objects (3) not equal to number of keys (8)'"
I can't understand for the life of me why the count would differ if when I print out the values array I see 8 values... which should match my 8 keys? and they are correct?
Any help/direction would be greatly appreciated!
Thanks,
Is the fourth item in your values array:
[result stringForColumn:#"image_portrait"]
returning nil? That's the value that tells -initWithObjects that the list is done.
I am trying to create this method. Let's call this
-(NSMutableArray*) getEightClosestSwatchesFor:(CGFloat)hue
{
NSString *myFile = [[NSBundle mainBundle] pathForResource:#"festival101" ofType:#"plist"];
NSMutableArray* myArray = [NSArray arrayWithContentsOfFile:myFile];
for (NSDictionary *dict in myArray)
{
NSLog(#"[plistData valueForKey:aKey] string] is %f", [[dict valueForKey:#"hue"] floatValue]) ;
}
return myArray;
}
pretty much, I am passing a cgfloat to this method which then needs to check a plist file which have hue key for 100 elements. I need to compare my hue with all of the hues and get 8 most closest hue and finally wrap these into an array and return this.
What would be most efficient way of doing this? Thanks in advance.
Here's my method if anyone is interested. Feel free to comment on it.
-(NSArray*)eightClosestSwatchesForHue:(CGFloat)hue
{
NSMutableArray *updatedArray = [[NSMutableArray alloc] initWithCapacity:100];
NSString *myFile = [[NSBundle mainBundle] pathForResource:#"festival101" ofType:#"plist"];
NSMutableArray* myArray = [NSArray arrayWithContentsOfFile:myFile];
for (NSDictionary *dict in myArray)
{
CGFloat differenceHue = fabs(hue - [[dict valueForKey:#"hue"] floatValue]);
//create a KVA for the differenceHue here and then add it to the dictionary and add this dictionary to the array.
NSDictionary* tempDict = [NSDictionary dictionaryWithObjectsAndKeys:
[dict valueForKey:#"id"], #"id",
[NSNumber numberWithFloat:differenceHue], #"differenceHue",
[dict valueForKey:#"color"], #"color",
nil];
[updatedArray addObject:tempDict];
}
//now we have an array of dictioneries with values we want. we need to sort this from little to big now.
NSSortDescriptor *descriptor = [[NSSortDescriptor alloc] initWithKey:#"differenceHue" ascending:YES];
[updatedArray sortUsingDescriptors:[NSArray arrayWithObjects:descriptor,nil]];
[descriptor release];
//now get the first 8 elements and get rid of the remaining.
NSArray *finalArray = [updatedArray subarrayWithRange:NSMakeRange(0,8)];
[updatedArray release];
return finalArray;
}
I'm having some troubles with the code below:
NSSortDescriptor *idDescriptor = [[[NSSortDescriptor alloc] initWithKey:key ascending:ascending] autorelease];
NSArray *sortDescriptors = [NSArray arrayWithObject:idDescriptor];
NSArray *orderArray = [array sortedArrayUsingDescriptors:sortDescriptors];
NSMutableArray *result = [NSMutableArray arrayWithArray:orderArray];
If I use this code, Instruments says I have a memory leak, why?
Using this code:
NSSortDescriptor *idDescriptor = [[[NSSortDescriptor alloc] initWithKey:key ascending:ascending] autorelease];
NSArray *sortDescriptors = [NSArray arrayWithObject:idDescriptor];
NSArray *orderArray = [array sortedArrayUsingDescriptors:sortDescriptors];
NSMutableArray *result = [[NSMutableArray alloc] initWithArray:orderArray];
I receive the leak warning too, however, if I autorelease the object result, a memory error happens.
Here is a better answer I think.
- (NSMutableArray *) orderArray:(NSMutableArray *)array ByKey:(NSString *)key ascending:(BOOL)ascending
{
NSSortDescriptor *idDescriptor = [[[NSSortDescriptor alloc] initWithKey:key ascending:ascending]];
NSArray *sortDescriptors = [NSArray arrayWithObject:idDescriptor];
NSArray *orderArray = [array sortedArrayUsingDescriptors:sortDescriptors];
NSMutableArray *result = [[[NSMutableArray alloc] initWithArray:orderArray]];
[release idDescriptor];
return [result autorelease];
}
So, you allocate idDescriptor, then you use it, finally release it. Since you're returning result, you can autorelease it with the return. I have one more question though. Do you reference result elsewhere in your code?
It is really mind boggling to find out many differences between the iphone and the simulators. I spent several hours trying to figure out why my application ran on the simulator but crashed on my iphone device. It turns out the culprit is sortedArrayUsingDescriptors. Are there more get-you like this? Please share with me.
To share with you on the issue and the fixes:
Code crashed on iphone but not simulator
NSSortDescriptor* aDescriptor = [[[NSSortDescriptor alloc] initWithKey:#"count" ascending:NO] autorelease];
NSArray* anNsArray = [[NSArray alloc] init];
NSArray* aSortedNsArray = [[NSArray alloc] init];
aSortedNsArray = [anNsArray sortedArrayUsingDescriptors:[NSArray arrayWithObject:aDescriptor]];
The issue is on [NSArray arrayWithObject:aDescriptor];
The fixes are to create an Array to store it:
NSArray* descriptorArray = [[NSArray alloc] initWithObjects:countDescrp, nil];
aSortedNsArray = [anNsArray sortedArrayUsingDescriptors:descriptorArray];
NSSortDescriptor* aDescriptor = [[[NSSortDescriptor alloc] initWithKey:#"count" ascending:NO] autorelease];
NSArray* anNsArray = [[NSArray alloc] init];
NSArray* aSortedNsArray = [[NSArray alloc] init];
aSortedNsArray = [anNsArray sortedArrayUsingDescriptors:[NSArray arrayWithObject:aDescriptor]];
This is a wrong initialization mechanism, and if the code snippet is complete, your problem lies on the anNsArray object that's empty.
You also do not need to initialize the aSortedNsArray.
So it should be:
NSSortDescriptor* sortDescriptor = [[[NSSortDescriptor alloc] initWithKey:#"count" ascending:NO] autorelease];
// Assume you return it as array of objects from a property or method
NSArray *array = [self objects];
NSArray *sortedArray = nil;
if ([array count] > 0) {
sortedArray = [array sortedArrayUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];
}
// Then you check the sortedArray
if (sortedArray == nil || [sortedArray count] == 0)
[self somethingIsWrong];
arrayWithObject: (autoreleased) or initWithObject: (manual) is just a different way to allocate NSArray object. It won't cause crashes normally. Because what you care about is the sortedArray not retaining the descriptors array object.