nsmutablearray - w3toppers.com

‘Invalid update: invalid number of rows in section 0

You need to remove the object from your data array before you call deleteRowsAtIndexPaths:withRowAnimation:. So, your code should look like this: // Editing of rows is enabled – (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath { if (editingStyle == UITableViewCellEditingStyleDelete) { //when delete is tapped [currentCart removeObjectAtIndex:indexPath.row]; [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade]; } } You can also simplify … Read more

NSMutableArray – force the array to hold specific object type only

Update in 2015 This answer was first written in early 2011 and began: What we really want is parametric polymorphism so you could declare, say, NSMutableArray<NSString>; but alas such is not available. In 2015 Apple apparently changed this with the introduction of “lightweight generics” into Objective-C and now you can declare: NSMutableArray<NSString *> *onlyStrings = … Read more

How to sort NSMutableArray using sortedArrayUsingDescriptors?

To sort your array of objects you: setup NSSortDescriptor – use names of your variables as keys to setup descriptor for sorting plus the selector to be executed on those keys get the array of descriptors using NSSortDescriptor that you’ve setup sort your array based on those descriptors Here are two examples, one using NSDictionary … Read more

The best way to remove duplicate values from NSMutableArray in Objective-C?

Your NSSet approach is the best if you’re not worried about the order of the objects, but then again, if you’re not worried about the order, then why aren’t you storing them in an NSSet to begin with? I wrote the answer below in 2009; in 2011, Apple added NSOrderedSet to iOS 5 and Mac … Read more

Cannot add items to an NSMutableArray ivar

I’m assuming you haven’t initialized listOfEvents. Make sure you do listOfEvents = [[NSMutableArray alloc] init]; in your class’s init method. Also make sure you release it in your class’s dealloc method.

NSMutableArray addObject not affecting count?

Is “giftees” initialized? If it is nil, [giftees count] will return 0 as well

NSMutableArray addObject not working

The “0x0” part is a memory address. Specifically, “nil”, which means your mutable array doesn’t exist at the time this is being called. Try creating it in your -init method: categories = [[NSMutableArray alloc] init]; Don’t forget to release it in your -dealloc.

How do I sort an NSMutableArray with custom objects in it?

Compare method Either you implement a compare-method for your object: – (NSComparisonResult)compare:(Person *)otherObject { return [self.birthDate compare:otherObject.birthDate]; } NSArray *sortedArray = [drinkDetails sortedArrayUsingSelector:@selector(compare:)]; NSSortDescriptor (better) or usually even better: NSSortDescriptor *sortDescriptor; sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@”birthDate” ascending:YES]; NSArray *sortedArray = [drinkDetails sortedArrayUsingDescriptors:@[sortDescriptor]]; You can easily sort by multiple keys by adding more than one to … Read more

Random Number Generator Objective-C iOS8 [duplicate]

A NSArray, or NSMutableArray is index based, so every entry has an unique index number to access it like myarray.objectAtIndex:1 And counting your array will be done by myarray.count Is that what you expected with your question?!? 🙂