pulling a value from NSMutableDictionary - ios

Question

Here's my code for returning a unique value for identical keys in a dictionary. Right now, in my log, my "objects array:" is 6 (3 sets of (2 objects with identical keys)), and my "dictionary:" returns values for 1 object from each set (3 unique values). In my 'for' statement:
for (id key in dict)
{
self.titlesArray = [NSMutableArray arrayWithObject:dict];
NSLog(#"titles: %#", self.titlesArray);
self.titlesArray = [[NSMutableArray alloc] initWithObjects:[dict valueForKey:key] ,nil];
NSLog(#"titles: %#", self.titlesArray);
}
The first log prints out the three unique values AND keys. The second prints only a single value for a single key (which is what I want.. but I need all three key values) So my problem now is that I am unable to pull a key for each unique value from the dictionary and add it to my titlesArray.
for (id key in dict)
{
self.titlesArray = [NSMutableArray arrayWithObject:dict];
self.titlesArray = [[NSMutableArray alloc] initWithObjects:[dict valueForKey:key] ,nil];
code isn't quite right.
PFQuery *query = [PFQuery queryWithClassName:#"Images"];
[query whereKey:#"recipientIds" equalTo:[[PFUser currentUser] objectId]];
[query orderByDescending:#"createdAt"];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
if (error) {
NSLog(#"Error: %# %#", error, [error userInfo]);
}
else {
// found messages!
self.objectsArray = objects;
NSMutableDictionary *dict = [[NSMutableDictionary alloc] init];
for(id obj in self.objectsArray){
PFObject *key = [obj valueForKey:#"titleLabel"];
if(![dict objectForKey:key]){
[dict setValue:key forKey:[obj valueForKey:#"titleLabel"]];
}
}
for (id key in dict) {
self.titlesArray = [NSMutableArray arrayWithObject:dict];
NSLog(#"titles: %#", self.titlesArray);
self.titlesArray = [[NSMutableArray alloc] initWithObjects:[dict valueForKey:key] ,nil];
NSLog(#"titles: %#", self.titlesArray);
}
NSLog(#"dictionary: %#", dict);
NSLog(#"Objects array is %d", [self.objectsArray count]);
[self.pickerView reloadComponent:0];

Answer 1

it looks like there is some type error in line
PFObject *key = [self.objectsArray valueForKey:#"titleLabel"];
it should be
PFObject *key = [obj valueForKey:#"titleLabel"];

Answer 2

It's happening in this line, isn't it:
if(![dict objectForKey:#"titleLabel"]){
[dict setValue:obj forKey:key];
}
}
You are setting "obj" as a value, no problem there, but then you are using "key" which is a PFObject, but NSDictionary requires a NSString for the key.
If PFObject contains a NSString property that you want to use, you can pass that in. For example, if PFObject has an NSString property called "name" you could call this:
if(![dict objectForKey:#"titleLabel"]) {
[dict setValue:obj forKey:key.name];
}
}
The relevant thing to notice is the types of the parameters when NSMutableDictionary defines this method, namely the (NSString*):
- (void)setValue:(id)value forKey:(NSString *)key

Answer 3

How does your PFObject look like. Does it have strings in it?. According to your question you already know that you can't pass a PFObject as key for dictionary. If your object is some what like this
interface PFObject : NSObject
{
NSString *keyString;
......
.Some other variables
}
Then you should be using it like this to set it as key
PFObject *key = [self.objectsArray valueForKey:#"titleLabel"];
if(![dict objectForKey:#"titleLabel"]){
[dict setValue:obj forKey:[key valueForKey#"titleLabel"]];
}

Answer 4

Here is the code I found to work. It takes the array and sorts through the keys to return only unique values for a specific key:
PFQuery *query = [PFQuery queryWithClassName:#"Images"];
[query whereKey:#"recipientIds" equalTo:[[PFUser currentUser] objectId]];
[query orderByDescending:#"createdAt"];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
if (error) {
NSLog(#"Error: %# %#", error, [error userInfo]);
}
else {
// found messages!
self.objectsArray = objects;
NSMutableDictionary *dict = [[NSMutableDictionary alloc] init];
for(id obj in self.objectsArray){
PFObject *key = [obj valueForKey:#"titleLabel"];
if(![dict objectForKey:key]){
[dict setValue:key forKey:[obj valueForKey:#"titleLabel"]];
}
}
for (id key in dict) {
self.titlesArray = [NSMutableArray arrayWithObject:dict];
[self.titlesArray addObject:dict.allKeys];
self.titlesArray = [self.titlesArray objectAtIndex:1];
}
NSLog(#"titles: %#", self.titlesArray);
[self.pickerView reloadComponent:0];