Inserting and Deleting Rows

As you'll probably be expecting by now, inserting and deleting rows is a multistage process that involves the tableView, the delegate, and the dataSource working in tandem with each other.

The process involves the following:

1. Putting the table into editing mode.
2. For each row, checking whether editing is allowed and displaying the editing controls if it is
3. Responding to the user's touches on the editing controls by sending a message to the dataSource
4. Updating the model
5. Updating the table's rows

The sequence of events, and the passing of messages between tableView, dataSource, and delegate, is illustrated in Figure 7–9.

Figure 7–9. Messages passed during tableView editing

At first glance, this looks horrendously complicated. It's actually not that bad, as you'll see as you step through it.