Objective-C Fundamentals

156 CHAPTER 7 Protocols
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UITableViewCellAccessoryDetailDisclosureButton
This method leaves the accessory view of the UITableViewCell as an open rightbracket
image in a blue background.
UITableViewCellAccessoryCheckmark
This method leaves the accessory view of the UITableViewCell as a checkmark
image.
In order for this delegate method to be called, your table view cell must have an accessory
for the user to tap. The accessory type of a cell is set during the creation of the
cell itself, usually in the tableView:cellForRowAtIndexPath:. UITableViewCell has
two methods for setting an accessory view:
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setAccessoryType:
This method takes a UITableViewCellAccessoryType parameter. Any other
object passed into this method will result in an error.
setAccessoryView:
If you want to have some other type of custom accessory presented in the accessory
view, use this method. It takes in a general UIView or any subclass of it. This
method is useful when you’re trying to style an application that doesn’t work
with the default accessory types provided by Apple. Be careful when providing
UIButtons here: you can get a single button firing off to two separate methods
when it’s tapped.
The following methods are similar to the tableView: accessoryButtonTappedFor-
RowWithIndexPath: except they’re called when any other section of a table view cell is
selected. Two points of entry are provided for the selection of a cell, willSelect and
didSelect. This is commonly done throughout other Apple-provided delegates. Multiple
methods like these exist to allow developers the ability to react to users at any
point during the application flow. willSelect is called before the didSelect, but a
call to willSelect is always followed by a call to didSelect:
- (NSIndexPath *)tableView:(UITableView *)tableView
willSelectRowAtIndexPath:(NSIndexPath *)indexPath
- (void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath
Just as there’s an entry point to react to the user selecting any given cell, the following
methods provide points at which to react when a cell is being deselected:
- (NSIndexPath *)tableView:(UITableView *)tableView
willDeselectRowAtIndexPath:(NSIndexPath *)indexPath
- (void)tableView:(UITableView *)tableView
didDeselectRowAtIndexPath:(NSIndexPath *)indexPath
It’s common for table views to have alternating background colors, as can be seen in
the App Store and iTunes Music Store. Some developers might think the background
colors should be set when they create the cell, either in the UITableViewCell subclass