Using a custom image for a UITableViewCell's accessoryView and having it respond to UITableViewDelegate

Sadly that method doesn't get called unless the internal button type provided when you use one of the predefined types is tapped. To use your own, you'll have to create your accessory as a button or other UIControl subclass (I'd recommend a button using -buttonWithType:UIButtonTypeCustom and setting the button's image, rather than using a UIImageView).

Here's some things I use in Outpost, which customizes enough of the standard widgets (just slightly, to match our teal colouring) that I wound up doing my own UITableViewController intermediary subclass to hold utility code for all other table views to use (they now subclass OPTableViewController).

Firstly, this function returns a new detail disclosure button using our custom graphic:

- (UIButton *) makeDetailDisclosureButton
{
    UIButton * button = [UIButton outpostDetailDisclosureButton];

[button addTarget: self
               action: @selector(accessoryButtonTapped:withEvent:)
     forControlEvents: UIControlEventTouchUpInside];

    return ( button );
}

The button will call this routine when it's done, which then feeds the standard UITableViewDelegate routine for accessory buttons:

- (void) accessoryButtonTapped: (UIControl *) button withEvent: (UIEvent *) event
{
    NSIndexPath * indexPath = [self.tableView indexPathForRowAtPoint: [[[event touchesForView: button] anyObject] locationInView: self.tableView]];
    if ( indexPath == nil )
        return;

    [self.tableView.delegate tableView: self.tableView accessoryButtonTappedForRowWithIndexPath: indexPath];
}

This function locates the row by getting the location in the table view of a touch from the event provided by the button and asking the table view for the index path of the row at that point.

I found this website to be very helpful: custom accessory view for your uitableview in iphone

In short, use this in cellForRowAtIndexPath::

UIImage *image = (checked) ? [UIImage imageNamed:@"checked.png"] : [UIImage imageNamed:@"unchecked.png"];

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
CGRect frame = CGRectMake(0.0, 0.0, image.size.width, image.size.height);
button.frame = frame;
[button setBackgroundImage:image forState:UIControlStateNormal];

[button addTarget:self action:@selector(checkButtonTapped:event:)  forControlEvents:UIControlEventTouchUpInside];
button.backgroundColor = [UIColor clearColor];
cell.accessoryView = button;

then, implement this method:

- (void)checkButtonTapped:(id)sender event:(id)event
{
    NSSet *touches = [event allTouches];
    UITouch *touch = [touches anyObject];
    CGPoint currentTouchPosition = [touch locationInView:self.tableView];
    NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint: currentTouchPosition];

    if (indexPath != nil)
    {
        [self tableView: self.tableView accessoryButtonTappedForRowWithIndexPath: indexPath];
    }
}

My approach is to create a UITableViewCell subclass and encapsulate the logic that will call the usual UITableViewDelegate's method within it.

// CustomTableViewCell.h
@interface CustomTableViewCell : UITableViewCell

- (id)initForIdentifier:(NSString *)reuseIdentifier;

@end

// CustomTableViewCell.m
@implementation CustomTableViewCell

- (id)initForIdentifier:(NSString *)reuseIdentifier;
{
    // the subclass specifies style itself
    self = [super initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:reuseIdentifier];
    if (self) {
        // get the button elsewhere
        UIButton *accBtn = [ViewFactory createTableViewCellDisclosureButton];
        [accBtn addTarget: self
                   action: @selector(accessoryButtonTapped:withEvent:)
         forControlEvents: UIControlEventTouchUpInside];
        self.accessoryView = accBtn;
    }
    return self;
}

#pragma mark - private

- (void)accessoryButtonTapped:(UIControl *)button withEvent:(UIEvent *)event
{
    UITableViewCell *cell = (UITableViewCell*)button.superview;
    UITableView *tableView = (UITableView*)cell.superview;
    NSIndexPath *indexPath = [tableView indexPathForCell:cell];
    [tableView.delegate tableView:tableView accessoryButtonTappedForRowWithIndexPath:indexPath];
}

@end