Create NSDictionary with keys and values when selected UICollectionViewCell - ios

Question

I have a UICollectionView with thumbnails. When user selects one or multiple images at same time, I have to create NSDictionary with keys and values. Key has to be a specific name. This is the final result I need to get.
(
image[0] = 75829457,
image[1] = 03480923,
image[2] = 58924589
)
Values here are obviously image ids. How can I do that? I need to send that NSDictionary via POST request, which is not a problem.
Any help would be appreciated.
Thank you.

Answer 1

create a method to get ImageDictionary
- (NSDictionary *) dictionaryWithImageArray:(NSArray *)imageArrayID
{
NSMutableDictionary *imageDict = [[NSMutableDictionary alloc] init];
for (int i=0; i<[imageArrayID count]; i++) {
[imageDict setObject:[imageArrayID objectAtIndex:i] forKey:[NSString stringWithFormat:#"image[%d]",i]];
}
return imageDict;
}
Convert that dict to json string
NSError *error;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:<Dict from above>
options:NSJSONWritingPrettyPrinted
error:&error];
NSString *jsonString= nil;
if (! jsonData) {
NSLog(#"Got an error: %#", error);
jsonString = #"";
} else {
jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
}
Set Http Body for your request
[request setHTTPBody: [jsonString dataUsingEncoding:NSUTF8StringEncoding]];

Answer 2

In your controller, declare a member variable NSMutableString *mutableString. Initialize mutableString in your init method to be empty.
- (void)collectionView:(UICollectionView *)aCollectionView didSelectItemAtIndexPath:(NSIndexPath)indexPath {
NSString *key = [NSString stringWithFormat:#"image[%d]", [indexPath row]];
NSString *value = // get the picture id
NSString *parameter = [NSString stringWithFormat:#"%#=%#", key, value];
if ([mutableString length] != 0)
[mutableString appendString:#"&"];
[mutableString appendString:parameter];
}
Then use an IBAction to confirm the selections, construct your POST request and send it, and then empty the mutable string.