iPhone Development Blog

The fantastic rumors finally faced reality today when Apple presented their new fall lineup of devices. Here are my thoughts as an iOS developer on today’s announcements.

Live Streaming

It was great to be able to watch a live stream of the event instead of having to refresh half a dozen browser windows from various live bloggers. Rumors claimed that this might be a load test of Apple’s new data center. In reality the stream was served by Akamai (Apple’s longtime CDN partner) as evident by the edgesuite.net URL.

New iPod Nano

A new touch screen that looks very much like iOS. Except according to an Apple spokesman backstage, it isn’t iOS. That’s too bad. This would be a fun little device to write apps for. We’ll keep our collective fingers crossed that Apple will allow iOS-like apps to run on this device in the future. In the meantime I’m sure the jailbreak community will take a closer look at what’s really under the hood and find a way to run code on it.

New iPod Touch

Nothing unexpected here. Slight disappointment that the main camera is rather poor. I wonder if that’s due to cost, a physical space constraint or a reflection of Apple’s intended audience for this device?

iTunes Ping

Apple is not content on just having an iTunes presence on Facebook, they want to be the social network. With 160 million credit card carrying iTunes users, they definitely have a running start. I really liked how they emphasized the privacy controls in Ping; a nice jab at Facebook.

As a developer I want an API to integrate with Ping. I think one of the critical success factors of Facebook is that they have established themselves as the social platform. A more integrated social platform within the iTunes/iOS ecosystem could be very interesting. Which of course begs the question of how does Game Center fit into this? Since both Game Center and Ping use iTunes accounts as the user identifier, it seems possible to merge or integrate the two in some way in the future.

New Apple TV

Smaller and cheaper, but nothing revolutionary. I love how Steve Jobs sells the idea of removing something (storage in this case) as a great benefit.

John Gruber claims that the new Apple TV does run iOS. It may be splitting hairs, but in my mind iOS implies UIKit, which is heavily oriented towards a touch interface, which I did not see much of in the demo. We’ll keep hoping that there will eventually be 3rd party apps and an App Store for the Apple TV.

For my media center, I will probably stick with my Mac Mini with Plex for now.

iOS Updates

iOS 4.1 is being released next week. Since we’ve had beta versions for a while, that’s no surprise. iOS 4.2 is coming in November which will be the first 4.x update for the iPad. While November technically qualifies as “fall”, it would have been nice to get all the 4.x goodness a bit sooner.

Overall 3 major OS releases within the span of 6 months is just a relentless pace. I wonder when the iOS development team at Apple last had a vacation? The competition is not sitting idle either, it’s definitely a great game to watch unfold. A huge benefit that Apple and iOS enjoys is the ease with which customers can upgrade to the latest iOS version. This greatly simplifies the life for us developers in that we can to a large degree assume the the latest version as a deployment target.

AirPlay

I think the most interesting announcement was AirPlay. This is an improved version of AirTunes. Now you can share audio, video, and photos with meta data between iOS devices (running iOS 4.2) and compatible accessories. A cool demonstration of this was at the very end when Steve Jobs was watching a movie on an iPad and then shared the video stream with an Apple TV. It’s not a stretch to imagine that the screen of any iOS app could be shared this way. I wonder if this is what the rumors about iOS apps on the Apple TV (nee iTV) were really based on.

written by Nick \\ tags: News

Apple made significant changes to the MPMoviePlayerController API:s in iOS 3.2. Before, all you had to do was to initialize the MPMoviePlayerController and call play. Now things are a bit more complicated because videos can be played on a portion of the screen (good for the iPad) and not just in full screen mode.

But if all you want is to play a video in full-screen mode on all versions of the OS, then here’s some code:

NSURL *url = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:introVideoFileName ofType:@""]];
MPMoviePlayerController *moviePlayer = [[MPMoviePlayerController alloc] initWithContentURL:url];

// Register to receive a notification when the movie has finished playing.
[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(moviePlayBackDidFinish:)
                                             name:MPMoviePlayerPlaybackDidFinishNotification
                                           object:moviePlayer];

if ([moviePlayer respondsToSelector:@selector(setFullscreen:animated:)]) {
  // Use the new 3.2 style API
  moviePlayer.controlStyle = MPMovieControlStyleNone;
  moviePlayer.shouldAutoplay = YES;
  [self.view addSubview:moviePlayer.view];
  [moviePlayer setFullscreen:YES animated:YES];
} else {
  // Use the old 2.0 style API
  moviePlayer.movieControlMode = MPMovieControlModeHidden;
  [moviePlayer play];
}

- (void) moviePlayBackDidFinish:(NSNotification*)notification {
  MPMoviePlayerController *moviePlayer = [notification object];
  [[NSNotificationCenter defaultCenter] removeObserver:self
                                                  name:MPMoviePlayerPlaybackDidFinishNotification
                                                object:moviePlayer];

  // If the moviePlayer.view was added to the view, it needs to be removed
  if ([moviePlayer respondsToSelector:@selector(setFullscreen:animated:)]) {
    [moviePlayer.view removeFromSuperview];
  }

  [moviePlayer release];
}

Recently I’ve been doing some development using cocos2d and I had to make some small changes to the code. (If your app is in portrait mode, then you may not have to do the rotation transform shown below.)

NSURL *url = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:introVideoFileName ofType:@""]];
MPMoviePlayerController *moviePlayer = [[MPMoviePlayerController alloc] initWithContentURL:url];

// Register to receive a notification when the movie has finished playing.
[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(moviePlayBackDidFinish:)
                                             name:MPMoviePlayerPlaybackDidFinishNotification
                                           object:moviePlayer];

if ([moviePlayer respondsToSelector:@selector(setFullscreen:animated:)]) {
  // Use the new 3.2 style API
  moviePlayer.controlStyle = MPMovieControlStyleNone;
  moviePlayer.shouldAutoplay = YES;
  // This does blows up in cocos2d, so we'll resize manually
  // [moviePlayer setFullscreen:YES animated:YES];
  [moviePlayer.view setTransform:CGAffineTransformMakeRotation((float)M_PI_2)];
  CGSize winSize = [[CCDirector sharedDirector] winSize];
  moviePlayer.view.frame = CGRectMake(0, 0, winSize.height, winSize.width);// width and height are swapped after rotation
  [[[CCDirector sharedDirector] openGLView] addSubview:moviePlayer.view];
} else {
  // Use the old 2.0 style API
  moviePlayer.movieControlMode = MPMovieControlModeHidden;
  [moviePlayer play];
}

written by Nick \\ tags: cocos2d, MPMoviePlayerController

I’ve updated the App Store Rejection Reasons page with a few new items related to the iPad UI.

written by Nick \\ tags: iPad

Today Apple announced their new iOS 4 Readiness Checklist. As a trailing sentence, almost as an afterthought, was this: “In addition, the App Store will no longer support applications that target iOS 2.x.”

That last sentence can be interpreted in several ways:

• You will no longer be able to upload apps to the App Store that target iOS 2.x.
• The App Store will really not support 2.x apps anymore and all such apps will therefore be removed.

The interpretation could have a significant impact on existing apps for several of our clients, so I called Apple for a clarification.

The official word is that going forward you will not be able to upload new or update existing apps that target iOS 2.x. All existing apps in the App Store will remain for sale even if they target iOS 2.x.

That of course is the sensible path. Although a general cleanup of the App Store to get rid of old apps that have not been updated since the 2.x days, might not be a bad idea…

written by Nick

My company, Pervasent, develops complex, enterprise class iPhone/iPad software. If that’s what you do, then please keep reading.

Please take a moment and look at our portfolio on our web site. If you have developed similar applications, then we definitely want to talk to you.

At Pervasent we really enjoy our work, and are looking for people who think developing iPhone/iPad applications is fun. We can’t wait to get to work (well, most of the time). We have the pleasure of working with other passionate developers, both on our own projects, and for our top-tier clients. We have been developing applications for the platform since the day it became available for third parties, so other than working for Apple, you can’t work with a more experienced team of developers than you can at Pervasent.

We have two immediate openings for an onsite project in San Francisco to work on a top 10 iPad app. For other projects, we are open to candidates in other locations. Please note that we only hire individuals, not companies. If you work for a consulting or contracting company and you want to offer *your* services, that’s fine, but then we want to see *your* qualifications, not your company’s aggregated portfolio.

These are contract to hire, or long-term contracting positions. And of course you will get paid for your work; no internships or revenue share BS.

All the developers in our company have 10-15 years of large scale, enterprise software development experience. If you have a similar background that’s a definite plus, but not a requirement. But design patterns, object modeling and data modeling must be ingrained in your thinking. Be prepared to answer questions more complex than “explain the benefits of an MVC architecture.”

You should have completed at least a couple of iPhone apps, either as an individual or as a part of a team. Please point us to your best apps in the App Store and describe your development role in each of them.

Beauty and quality comes from within, so at some point we will need to do a code review of something that you have written (this can occur in person on your equipment; we don’t expect you to send us your crown jewels). If that scares you, then this would be a good point to stop reading.

Finally, and most importantly, please tell us why you’re passionate about developing iPhone/iPad apps.

Thank you for your time and attention. We look forward to hearing from you.

written by Nick \\ tags: jobs

My iPhone 4 just arrived. Here are my initial thoughts.

Retina Display

The first thing you notice as soon as you turn on the iPhone 4 is the new display. It is absolutely gorgeous. Not only is the resolution so much higher, but the pixels are also much closer to the glass, which combined creates a stunning effect. Sometimes when you walk into an electronics store they have dummy versions of some gadgets which have a sticker on the front panel to show you what it would look like if you could turn it on. The iPhone 4 display looks like that with the image right at the surface and with the same resolution as print.

Any text rendered in your app will automagically be rendered in the higher resolution on the iPhone 4. But any graphics will be scaled up. The graphics don’t look nearly as bad as the 2x mode on the iPad, but you definitely notice the difference in sharpness. For example compare the icons of the built-in Apple apps with the surrounding icons that have not yet been optimized for the new display.

Speaking of icons: Here’s a nice overview of all the different icon sizes that you should be creating for your apps to take full advantage of the screen resolution of each device. There are more sizes on this list than you think…

Speed

Having upgraded from an old iPhone 3G as my daily device, the speed of the iPhone 4 seems blazing. Everything is faster including installing apps and backups. It’s very easy to get spoiled. But keep in mind that a majority of your customers don’t have the iPhone 4. My main development and testing device is still a first generation iPod Touch. And I’m not done with my performance tuning until it runs fast on that device.

Fast Task Switching

The world has demanded “multitasking” on the iPhone, and Apple’s marketing department has delivered. In all seriousness, the engineers have implemented a really good mechanism for quickly switching between apps. However, as a user I still find it confusing. This is mostly because apps behave inconsistently when you launch/resume.

To participate in fast task switching you need to recompile your code using the 4.0 SDK. WIthout recompiling, your app will behave just like it does today under iOS 3.x and earlier: the app fully exits and launches from scratch each time. (Yes, I know that old apps still show up in the task bar when you double-click the Home button. But that’s because the task bar is a list of recently launched apps, most of which are no longer resident in memory, and even fewer are actually running.)

But you shouldn’t stop with a simple recompile. The important, and difficult, part is to maintain and restore the application state. If your app happens to be still in memory when it’s relaunched, then the state of the app will be just like the user left it. This is what the user expects. But if your app has been terminated, perhaps because the OS needed to reclaim the memory, then it will be launched from scratch. In this case it’s your responsibility to completely restore the state. The user has no idea of what the OS is doing behind the scenes, so the behavior of your app should not vary between these two situations.

written by Nick \\ tags: iPhone 4

In Session 147 – Advanced Performance Optimization at WWDC last week Apple put up a slide that listed the amount of memory in each iDevice. At the time there was an audible gasp from the audience followed by frenetic note taking. As far as I know this was the first time Apple has ever officially confirmed the amount of memory in these devices. Since all WWDC sessions are covered by a special NDA, I cannot reveal the contents of the slide. But if you go 1:55 into the WWDC video you can see it for yourself.

It has been widely reported that the iPhone 4 will have twice the memory of the iPad. This is curious since at the time the iPad was released with the new A4 SOC with the integrated memory in the chip, it was assumed there was a physical limitation to the amount of memory that could be put in the SOC. It is great to see that Apple has broken through that barrier.

Having the exact same chip in the iPhone 4 as the iPad would make sense to gain efficiencies from scale. And given Apple’s margins on their products I can’t imagine that bumping up the memory would be too much of a financial burden. So why not quietly upgrade the iPad processor with the iPhone 4 version that has double the memory? Isn’t this why Apple never advertises the amount of memory in their iDevices, so they have the flexibility to make changes at their convenience?

written by Nick

Xcode and the iPhone development environment has it’s share of cryptic error messages. I encountered the one in the headline the other day.

I was working on an app that has been in development for many months and attempting to deploy the app to a device for testing. I’ve done countless times in the past, but this time Xcode simply said:

(gdb) run
Running…
Error launching remote program: security policy error.
The program being debugged is not being run.

Opening the Organizer window and checking the device log revealed this:

error: unable to launch the application with CFBundleIdentifier 'com.foo.bar' sbs_error = 9

A security policy error is usually associated with your development certificate or provisioning profile. And these have a tendency to expire at the most inopportune times. But that was not the case this time.

However it turned out that in addition to the valid provisioning profile, this device also had an old, recently expired provisioning profile installed. This was apparently too much for the device. After removing the old provisioning profile, everything started working again.

So now you know one reason why your development devices keep reminding you about expiring provisioning profiles. It’s important that you remove them when they expire.

written by Jess \\ tags: error message, provisioning profile

It’s clear that Apple is feeling the heat from the competition in the mobile space. Matt Drance eloquently analyzed Steve Jobs keynote presentation on the first day. The avalanche of information just accelerated during the rest of the week. The expression “drinking from a fire hose” came up frequently in conversations during the week.

In a previous life I was an enterprise Java architect and dutifully made the annual pilgrimage to the JavaOne conference. In the beginning of Java, the language and the API:s were small enough that you could grasp everything. But at one point everything exploded and there was no way to keep up with all the new API:s and all the new things Java was attempting to do. I feel that we’re approaching that point with iOS (formerly known as the iPhone OS).

The complexity of the platform has also increased. Take multitasking for example. Managing database connections and open sockets when your app is transitioned between the active/inactive/running/background running/suspended states, is not trivial. Neither is scheduling a background task to complete when your app is about to stop running, while also dealing with the fact that the background task can also be interrupted. And this is just one set of new API:s.

Recently I’ve been doing some code reviews for clients. One of the first things I do is to run the static analyzer. When that comes back with 170 warnings, I get disappointed. Why would you as a developer ever release code that has over a hundred memory warnings? Especially when the static analyzer is one of the easiest Xcode tools to run: just select Build and Analyze instead of Build from the Build menu. Apple is releasing a slew of new tools and instruments to help you analyze and tune your iOS apps. These tools are very powerful, and they definitely have a learning curve.

Don’t get me wrong; I’m not complaining. On the contrary I think this is all great for us professional iPhone developers. Keeping your skills up to date with the latest tools and technologies is the best way to stay ahead of the pack. For consumers it’s even better. Without investing any time or effort we get to enjoy the fruits of the accelerated innovation coming out of Apple and the competition.

written by Nick \\ tags: conference

Sorry about the lack of posts here lately. I’ve been working overtime to clear the decks with existing projects so that I can enjoy WWDC.

If you’re at WWDC don’t hesitate to say hi if you see me. I’m also open to party invitations and more serious meetings to explore business opportunities.

written by Nick