Have a reloadData for a UITableView animate when changing

Question

I have a UITableView that has two modes. When we switch between the modes I have a different number of sections and cells per section. Ideally, it would do some cool anima

Answer 1

All of these answers assume that you are using a UITableView with only 1 section.

To accurately handle situations where you have more than 1 section use:

NSRange range = NSMakeRange(0, myTableView.numberOfSections);
NSIndexSet *indexSet = [NSIndexSet indexSetWithIndexesInRange:range];
[myTableView reloadSections:indexSet withRowAnimation:UITableViewRowAnimationAutomatic];

(Note: you should make sure that you have more than 0 sections!)

Another thing to note is that you may run into a NSInternalInconsistencyException if you attempt to simultaneously update your data source with this code. If this is the case, you can use logic similar to this:

int sectionNumber = 0; //Note that your section may be different

int nextIndex = [currentItems count]; //starting index of newly added items

[myTableView beginUpdates];

for (NSObject *item in itemsToAdd) {
    //Add the item to the data source
    [currentItems addObject:item];

    //Add the item to the table view
    NSIndexPath *path = [NSIndexPath indexPathForRow:nextIndex++ inSection:sectionNumber];
    [myTableView insertRowsAtIndexPaths:[NSArray arrayWithObject:path] withRowAnimation:UITableViewRowAnimationAutomatic];
}

[myTableView endUpdates];