Category: Development

Another area where I find iPhone development to be a bit convoluted was with toolbars and action sheets. The sheets are conceptually tied to the toolbar, yet there is no glue to combine UIActionSheet with UIToolbar. It’s also fairly difficult to represent your application state in the toolbar—an example is the refresh button in Twitterrific that turns into a cancel button while the refresh is taking place.

And then one day it dawned on me: an iPhone toolbar with an action sheet is like a menubar with menus on the Mac desktop (turn your phone upside down and there is even some visual similarity.)

After investigating some of the design patterns for NSMenu and NSMenuItem, it was clear that this would work well on a mobile interface as well. My implementation is a subclass of UIToolbar named IFActionToolbar.

In it’s simplest form, you attach a list of items to one of the toolbar’s bar button items:

@interface MyViewController : UIViewController
{
  IBOutlet IFActionToolbar *toolbar;
  IBOutlet UIBarButtonItem *barButtonItem;
}

...

@implementation MyViewController  

...

- (void)viewDidLoad
{
  [super viewDidLoad];

  IFActionToolbarActionItem *actionItem = nil;

  NSMutableArray *actionItems = [NSMutableArray arrayWithCapacity:3];
  actionItem = [[[IFActionToolbarActionItem alloc] initWithTitle:@"One" target:self action:@selector(firstAction:)] autorelease];
  [actionItems addObject:actionItem];
  actionItem = [[[IFActionToolbarActionItem alloc] initWithTitle:@"Two" target:self action:@selector(secondAction:)] autorelease];
  [actionItems addObject:actionItem];
  actionItem = [[[IFActionToolbarActionItem alloc] initWithTitle:@"Cancel" target:nil action:NULL] autorelease];
  [actionItems addObject:actionItem];
  [toolbar attachActionItems:actionItems toItem:barButtonItem];

  [toolbar update];
}

The IFActionToolbarActionItem is just a simple wrapper object that associates a title with a target and action. These action items are used to automatically construct the action sheet when the user taps on barButtonItem. If you’ve ever constructed an NSMenu using NSMenuItems, this will feel quite familiar.

Additionally, the toolbar supports an -update method. This method calls the assigned delegate to enable or disable toolbar buttons, set the image for the toolbar item, change the title of the action sheet, hide or show items in the action sheet, and define the cancel or destructive buttons in the sheet. Again, similar in pattern to how NSMenuItems are maintained.

Any time you call this update method, the UIToolbar is configured automatically. It makes it much easier to reflect the state of your controller in the view.

I’m not going to spend too much time discussing the inner workings of this class: the picture of a sample project is worth a thousand words.

One thing I would like to caution you about: don’t get too carried away with enabling and disabling items in the action menu. In our UI testing, we found that changing the list too much was confusing for users. It’s like the “adaptive menus” used in Microsoft Office: it’s very difficult for a user to adapt to your interface if it’s constantly changing. Just because you can doesn’t mean you should.

Again, I hope this code is useful in your own iPhone projects. Enjoy!

Every once in awhile you read a blog post that completely changes the way you think about a problem. Matt Gallagher’s Cocoa With Love is one of those blogs where it happens often. If you’re not subscribing to his RSS feed, do it now.

In particular, this post addressed a problem that every iPhone developer has encountered: any kind of settings or form UI is a pain in the butt if you follow Apple’s sample code. And, of course, this is exacerbated because these essential interfaces aren’t very fun to code. For both Twitterrific and Frenzic, it’s been a frustrating experience: I wanted to fix how this standard UI was created and maintained.

The motivation

Before I start talking about what I did using Matt’s concepts and code, I’d like to discuss the need for settings in an application.

There are some people who think that settings should only be in the Settings app. There are others that think they should only be within the application. I can honestly see how both groups are right, but what both sides fail to realize is that it’s often a matter of context.

If you’re working on a simple application with simple needs, relying on the infrastructure provided by the SDK is fine. You may have some additional support load for users who have problems finding your settings, but that’s a reasonable tradeoff for saving development time. Sophia Teutschler’s Groceries app is a fine example of where the built-in settings shine: I turned off the Marker Felt font several months ago, and I haven’t touched it since.

In the case of Twitterrific, there were three main reasons why we built the settings into the application:

1. We could not split the settings between two locations. From a user’s point-of-view, it’s incredibly confusing to have an application’s configuration in two places. This would have happened if we had put the account settings in the application and everything else in the Settings app.
2. Some of the settings are things that people will change on a fairly frequent basis. For example, the dark theme works best at night, while a light theme is better during the day. Leaving the app to make these types of adjustments is inconvenient.
3. The Settings app can’t handle preferences that are “dynamic.” An example is a vibration setting for the notification: there’s no way to make this appear on an iPhone but not on an iPod touch.

The solution

I’ve taken the basic concepts that Matt presented in his article and extended them to create a pixel perfect replica of what you see in the Settings application. Instead of configuring applications using a property list, you do it with some very simple code in a view controller. (Domain-specific languages, such as those found in Ruby, were an inspiration for the methods used in this code.)

And if you’re not doing settings, the classes are still very handy for making user input forms. They were used in all of the search forms used in the new version of Twitterrific.

To give you a quick taste of how it’s used, here’s a complete implementation of a table view controller that presents a single group with a text field and a switch control. In just six lines of code:

- (void)constructTableGroups
{
  NSMutableArray *cells = [NSMutableArray array];
  IFTextCellController *textCell = [[[IFTextCellController alloc] initWithLabel:@"Text" andPlaceholder:@"Placeholder" atKey:@"sampleText" inModel:model] autorelease];
  [cells addObject:textCell];
  IFSwitchCellController *switchCell = [[[IFSwitchCellController alloc] initWithLabel:@"Switch" atKey:@"sampleSwitch" inModel:model] autorelease];
  [cells addObject:switchCell];
  tableGroups = [[NSArray arrayWithObject:cells] retain];
}

The real beauty of this code is that it’s incredibly easy to change. Settings and forms tend to evolve over the lifetime of a project, so using these simple declarations for the table view layouts makes it much simpler to adapt to new requirements. If I need to change the switch control shown above into a choice list, I can do it in a couple of lines of code.

So without further ado, here’s the source code in a sample project. The code is well documented, so you shouldn’t have any problems figuring out how it all works. Start by looking at the RootViewController, then take a look at the SampleViewController, followed by the SampleAdvancedViewController. If you’d like to incorporate this code into your own project, just grab all the classes with the Iconfactory prefix (“IF”.)

The license

Previously, I’ve released source code on this site without any licensing at all. This time, I’m going to try something new. You can do anything you want with this code with one requirement: you need to give the Iconfactory some link love in your product.

For more details on the licensing terms, check out the Licensing.rtf file that’s included in the sample project. If you can’t abide by this restriction, please get in contact and we can try to work something out.

I hope this code saves you as much time as it has saved me. Enjoy!