iOS 7 Programming Cookbook

4.2. Using Different Types of Accessories in a Table View Cell

Problem

You want to grab users’ attention in a table view by displaying accessories and offer different ways to interact with each cell in your table view.

Solution

Use the accessoryType of the UITableViewCell class, instances of which you provide to your table view in its data source object:

- (UITableViewCell *)tableView:(UITableView *)tableView
         cellForRowAtIndexPath:(NSIndexPath *)indexPath{

    UITableViewCell* result = nil;

    if ([tableView isEqual:self.myTableView]){

        result = [tableView
                  dequeueReusableCellWithIdentifier:MyCellIdentifier
                  forIndexPath:indexPath];

        result.textLabel.text =
        [NSString stringWithFormat:@"Section %ld, Cell %ld",
         (long)indexPath.section,
         (long)indexPath.row];

        result.accessoryType = UITableViewCellAccessoryDetailDisclosureButton;

    }

    return result;

}

- (NSInteger) tableView:(UITableView *)tableView
  numberOfRowsInSection:(NSInteger)section{
    return 10;
}

- (void)viewDidLoad{
    [super viewDidLoad];

    self.myTableView = [[UITableView alloc]
                        initWithFrame:self.view.bounds
                        style:UITableViewStylePlain];

    [self.myTableView registerClass:[UITableViewCell class]
             forCellReuseIdentifier:MyCellIdentifier];

    self.myTableView.dataSource = self;

    self.myTableView.autoresizingMask =
        UIViewAutoresizingFlexibleWidth |
        UIViewAutoresizingFlexibleHeight;

    [self.view addSubview:self.myTableView];

}

Discussion

You can assign any of the values defined in the UITableViewCellAccessoryType enumeration to the accessoryType property of an instance of the UITableViewCell class. Two very useful accessories are the disclosure indicator and the detail disclosure button. They both display a chevron indicating to users that if they tap on the associated table view cell, a new view or view controller will be displayed. In other words, the users will be taken to a new screen with further information about their current selector. The difference between these two accessories is that the disclosure indicator produces no event, whereas the detail disclosure button fires an event to the delegate when pressed. In other words, pressing the button has a different effect from pressing the cell itself. Thus, the detail disclosure button allows the user to perform two separate but related actions on the same row.

Figure 4-3 shows these two different accessories on a table view. The first row has a disclosure indicator, and the second row has a detail disclosure button.

Figure 4-3. Two table view cells with different accessories

If you tap any detail disclosure button assigned to a table view cell, you will immediately realize that it truly is a separate button. Now the question is: how does the table view know when the user taps this button?

Table views, as explained before, fire events on their delegate object. The detail disclosure button on a table view cell also fires an event that can be captured by the delegate object of a table view:

- (void)                        tableView:(UITableView *)tableView
 accessoryButtonTappedForRowWithIndexPath:(NSIndexPath *)indexPath{

    /* Do something when the accessory button is tapped */
    NSLog(@"Accessory button is tapped for cell at index path = %@", indexPath);

    UITableViewCell *ownerCell = [tableView cellForRowAtIndexPath:indexPath];

    NSLog(@"Cell Title = %@", ownerCell.textLabel.text);

}

This code finds the table view cell whose detail disclosure button has been tapped and prints the contents of the text label of that cell into the console screen. As a reminder, you can display the console screen in Xcode by selecting Run → Console.