How to display json file data to UICollectionView - ios

Question

Here I tried to get data from my URL used base64,shaa256 for authorize Header and I just tried to display in my console. It's worked well. But I need to convert to NSDictionary and to display to my UICollectionView. And my data having 3 sections with different data. Each section having 12 - 20 files.
So my question are:
How to convert my url to json to NSDictionary ?
Hoe to display with 3 section & each section should have 12 to 20 data files?
I used only this code in my viewdidload to get data.does i need to add 1.Connection did receive response 2.Connection did receive data 3.connection didFailWithError 4.connectionDidFinishLoading to my code or don't want these 4 method to add in to my code
Here is my code:
I use to insert my below code to my above code after
NSString *str = [[NSString alloc] initWithData:returnData
encoding:NSUTF8StringEncoding];
NSError * error;
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:str
options: NSJSONReadingMutableContainers
error: &error];
NSLog(#"%#",json);
But it din't work.if any useful answer for my 3 question is very useful for me.i am new to ios.help me out.Thanks in advance !

Answer 1

The data will most probably be JSON and not plain text? So convert the response straight to NSDictionary:
// show loading indicators when you are fetching data
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
// hide loading indicators when you received a response
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
if (connectionError) {
// Handle error
} else {
NSDictionary *jsonResults = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil];
NSLog(#"jsonResults: %#", jsonResults);
// reload your views
// [self.myCollectionView reloadData];
}
}];
To make the collectionView with 3 sections you would need to have an NSArray containing the 3 sections, each of these 3 arrays would contain the 12-20 dictionaries with keys and values that will populate each cell.
NSArray *sectionOne = #[#{#"Section":#"1", #"Object":#"1"}, #{#"Section":#"1", #"Object":#"2"}];
NSArray *sectionTwo = #[#{#"Section":#"2", #"Object":#"1"}, #{#"Section":#"2", #"Object":#"2"}];
NSArray *sectionThree = #[#{#"Section":#"3", #"Object":#"1"}, #{#"Section":#"3", #"Object":#"2"}];
NSArray *collectionData = #[sectionOne, sectionTwo, sectionThree];
NSLog(#"collectionData: %#", collectionData);