How to sort UITableView sections - ios

Question

I have an array of objects with date inside.
Now I need to group my objects in UITableView by this date.
For examle:
0-{10-14; Obj1};
1-{10-14; Obj2};
2-{10-15; Obj3};
3-{10-15; Obj4};
I need to view it on my UITableView like this
10-14
0-{10-14; Obj1};
1-{10-14; Obj2};
10-15
2-{10-15; Obj3};
3-{10-15; Obj4};
To resolve I've done next; I've splited my array into NSDictationary with this code:
NSMutableDictionary *preResult = [[NSMutableDictionary alloc] init];
for (ClientMessage *message in array) {
NSMutableArray *mArray = [preResult objectForKey:message.formattedDate];
if (mArray == nil) {
mArray = [[NSMutableArray alloc] init];
[preResult setObject: mArray forKey:message.formattedDate];
}
[mArray addObject:message];
}
And my Table view shows me what i want, but it shows in wrong order; (my array was sorted by date)
I know tha i can't sort NSDictationary, in that case how can i sort my values in table view? Or Is there another way to group my values without NSDictationary?

Answer 1

Once you've finished loading the dictionary with all the values, you'll want to sort each array within the dictionary...
for (NSString *key in [preResult allKeys])
{
NSMutableArray *mArray = [preResult objectForKey:key];
// sort array to achieve the desired result
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:#"formattedDate" ascending:YES];
NSArray *sortedArray = [mArray sortedArrayUsingDescriptors:#[sortDescriptor]];
// reset newly sorted array for key inside the dictionary
[preResult sortedArray forKey:key];
}