iOS/Web Developer's Life in Beta

As with most things, the amount of work we as developers see when starting an iOS application is just the tip of the iceberg. There’s artwork, “About” screens, tutorial pages, icons, the app’s website, and all the marketing the app needs to get it out there. Even writing the app’s description or taking screenshots for the App Store is a time-consuming process. So anything I can do to cut down on the time needed to release my app, the better I am. Therefore when I decided to have myDrumPad translated to other languages to widen my user-base, I wanted to do make it as painless as possible.

I tried tried to have friends and family who understood foreign languages help with translations, and while they were very well intentioned it really didn’t work out in the end.  What I discovered was that there really is no substitute for hiring a trained professional.  But luckily it doesn’t have to be outrageously expensive. Read on for more.

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I’m a big fan of all things Apple, and as you can tell from my past blog posts I’m a big fan of iPhone development. I’ve even dusted off my aging C skills, and have learned to love Objective-C. The one thing I haven’t learned to love, like all other iPhone app developers, is their application release process, and the seemingly arbitrary app store acceptance department.

Don’t get me wrong, I think how Apple fiercely guards the App Store to prevent bad, buggy, or offensive material from getting on there is a great thing. Some of my mother-in-law’s students in the class she works in have iPhones or iPod Touches, and these little 10-year-olds love the little apps I’ve put out. They’re fun, light-hearted, and they get a lot of enjoyment out of these and other apps. It’s reassuring to know that if I install an app, it won’t crash my phone (too badly) or that a child won’t be offended by them (too much).

However, the level of detail they give in their rejections seem both arbitrary and unnecessary. You develop an app and have to throw it over the fence to Apple, after which you wait with no level of detail as to the status, or success, or any sense of progress through whatever queue they have. Finally, you more often than not get a big fat rejection letter that gives you no detail as to why your app didn’t meet their secret criteria.

In my experience so far, this has actually been a virtue. My apps actually did have minor race conditions, or problems on specific platform versions. So, fair enough, I fix my changes and submit them in. But recently, the framework I work with and have been helping develop seems to be under fire from Apple for no apparent reason. And it’s the contradictory nature of their message that is what gets under my skin.

In this long thread on the PhoneGap mailing list, a number of developers writing their applications under PhoneGap have been given rejection letters saying something like:

Upon review of your application, cannot be posted to the
App Store due to the usage of private API. Usage of such non-public
API, as outlined in the iPhone SDK Agreement section 3.3.2 is
prohibited:

” An Application may not itself install or launch other executable
code by any means, including without limitation through use of a plug-
in architecture, calling other frameworks, other APIs or otherwise.
No interpreted code may be downloaded and used in an Application
except for code that is interpreted and run by Apple’s Published APIs
and built-in interpreter(s).

The PhoneGap API implemented in your application is an external
framework.

For those new to PhoneGap, it’s a project that gives you an XCode project directory with Obj-C classes pre-made that allow you to develop iPhone apps in HTML / JavaScript. It wraps up several of the iPhone’s native controls and exposes those capabilities to JavaScript. In this way, an application developer could write their app in a hybrid of native Objective-C code and the iPhone’s own native browser control, the UIWebView.

It seems though that Apple constitues the use of their own controls as a 3rd-party library. Apple’s own developer documentation includes code sample projects, much like PhoneGap’s, intended to get a developer started on using their SDK. Is it incorrect to assume that others can do the same?

Additionally, there are 3rd-party companies such as AdMob, Medialets, and a number of others that provide ads, application tracking, and other resources to iPhone developers. Their code is given to you as pre-compiled libraries, that are most certainly not included on the iPhone when you pull it out of its shrink-wrap. So how is it that all these apps are released to the App Store with these 3rd-party libraries linked in, and an app framework whose source code is freely available and uses officially documented features can’t be?

I decided to put an end to the speculation, and wrote a letter to Apple’s developer support on this matter. I’ll give it a chance to percolate through their support department, and if I don’t hear an answer back via email, I plan to call their support department until I can get an answer.

For future reference, and in the interests of keeping the discussion open, here’s a copy of the letter I sent in to Apple.

From: Michael Nachbaur
Date: May 17, 2009 6:04:28 PM PDT (CA)
To: idp-dts@apple.com
Subject: Library classification clarification

Hello, I’m an iPhone software developer, and one of the core developers of the PhoneGap project. A number of users of PhoneGap – a set of Objective-C classes aimed at leveraging the UIWebView to access iPhone-supported hardware features – have reported that their apps have been rejected from the App Store because they supposedly use a “3rd-Party Library”. I wanted to get some clarification about this, as this is not only untrue, it is completely at odds with the goals of our project.

PhoneGap only uses officially-supported features of the iPhone, as documented within XCode’s iPhone SDK documentation. We even make sure that we don’t even use deprecated features of the iPhone, as we want to ensure 100% compatibility. All the software we use is exposed natively by the iPhone, and is in use in many other apps on the App Store.

So I wanted to get an official clarification from Apple as to why these apps are being rejected, and what, if anything, we as the maintainers and developers of the PhoneGap project can do to rectify the situation. We are trying to empower developers with quality starting-blocks for developing their own applications, much as the Apple sample applications do.

So please, if there’s anything we’re doing wrong, we would more than happily change our code to accommodate Apple’s policies. As far as we can tell, we support Apple’s licenses even better than other apps on the App Store, because we don’t import 3rd-party libraries such as AdMob, Medialets, or any of the other ad and tracking libraries that are obviously featured on almost every app in the App Store. And these are quite plainly 3rd-party libraries, and as such should they not be even more restricted than we are?

As a community, of both software developers and of business-people, we are very anxious to hear back from you, and would like to discuss this with someone at Apple to get an official answer, instead of the conversation being one-sided and filled with speculation.

Thank you for your time, and I look forward to hearing back from someone soon.

What are your thoughts on the matter? Can anyone reading this find some reason why Apple would target PhoneGap?

Update: I got an update on this problem from Steve, one of the app reviewers, over at Apple.

I’ve merged the results of my UIControls branch on github into my master branch. I think my little experiment went well, and I’d love to get feedback from people on how this new API works for you. I still have some great plans for it, but before I get ahead of myself, let me cover what I’ve done:

Changes:
• Refactored the command call API to allow for a richer set of arguments to PhoneGap commands
• Moved some commands around to more appropriate classes (e.g. Alert and Vibrate both moved to Notifications)
• Reorganized the XCode project so commands are clearly separated from PhoneGap infrastructure
• Renamed the Settings.plist PhoneGap config file to PhoneGap.plist, and created a new Settings.plist file that contains custom application-specific configuration.
• Made all PhoneGap commands inherit from a common base-class that auto-loads its own Dictionary of configuration from the main PhoneGap.plist file.
• Added UIControls command class that exposes tab bars and toolbars to JavaScript.
• Updated the demo to show off tabs and toolbars

All that looks like a big change, but almost all of it was infrastructure changes that were necessary to get UIControls to work. Previously, all PhoneGap commands were class method calls, meaning it was very difficult to maintain state between command calls. Now that commands are actually called on an instance of a given command class, it’s easier to maintain state. So when a tab bar is created, multiple calls can be made, each to construct different aspects of the UI. Without all this, the following example would have been much more complicated:

uicontrols.createTabBarItem(“toprated”, “Top Rated”, “tabButton:TopRated”);
uicontrols.createTabBarItem(“recents”, “Recents”, “tabButton:Recents”);
uicontrols.createTabBarItem(“more”, “More”, “tabButton:More”);
uicontrols.showTabBar();
uicontrols.showTabBarItems(“toprated”, “recents”, “history”, “more”);

The changes to the PhoneGap configuration were necessary because now, when a PhoneGapCommand subclass is constructed, it will look in the PhoneGap.plist configuration file to see if there’s anything pertaining to it. So if there’s a key in the dictionary with the same name as the class being constructed, it will use that as a local configuration dictionary influencing just that one class. That way, if you don’t use a feature of PhoneGap, or you have to configure a lot of options for a single type of command, these options won’t be cluttered alongside the standard global PhoneGap settings.

I created Settings.plist because of experiences I had in an application I’ve been creating in order to test my new UIControls branch changes. I found that I wanted to set compile-time options (for instance a “lite_mode” boolean) that influenced the way my app runs, without having to change HTML or JavaScript code every time. So instead what I have is a configuration plist file that is used exclusively in JavaScript for my application. I’ve added the excellent SB-JSON framework in to the PhoneGap project, and use that to pass these settings into the JavaScript application at start-up time. So all you have to do is read Settings.lite_mode, for instance, in order to read properties set in your plist file.

Oh, and finally, I’ve moved the JavaScript documentation to javascript/docs, since they were practically impossible for new users to find in the past. I’ve been working on creating DoxyGen docs of the PhoneGap code for use in XCode’s documentation browser, but I haven’t gotten far enough there to actually check anything in besides comments. I found instructions on how to generate XCode docsets from DoxyGen, but I haven’t gotten it working just yet.

So please, try out my PhoneGap updates and let me know what you think of it. I think the integration of the JSON framework will make things like Contacts much simpler to implement.

Before I go though, I want to give a little “wish list” of features I’m planning on adding in the near future. I’ll get to them whenever I can, since my own app development takes priority of course.

• Toolbar buttons
• Tabbar show/hide animations
• File support (read / write local files)
• Camera and photo library support (POST to a server, save to a local file, etc)
• Native “Flip / Slide” transitions (no more having to mimic them in CSS)
• 3rd party API integration, like AdMob and Medialets (I already have both of these done, but I’m in discussions with both companies to determine if the terms of their license allows me to redistribute it)

Last Thursday I went down to Nitobi after work for a couple of beer and a chat about PhoneGap before I had to go give a couple lightning talks at the Vancouver.pm Perl Mongers group. My hour chat with a couple of the Nitobi crew turned into over 2 hours, making me late for Vancouver.pm, but I think the effort was worth it. First off, they have good taste in beer. Second, I had an opportunity to do a little show-and-tell of my PhoneGap branch on Github. Not only did they like my changes, but I told them what my roadmap of features for PhoneGap includes, and I think they’re on board.

So to that end, I’ve started with the changes I said I’d work on. I cleaned up the console / debug logging code I recently developed, to allow for the main meat of what I’m working on: A flexible API for dynamically creating native UI widgets such as toolbars and tabbars. But before I can do that, I wanted to refactor the calling method that PhoneGap uses.

In order to make PhoneGap commands stateful, and to be able to pass a richer set of instructions to those commands, I’m refactoring the call API to look like so:

gap://Class.Method/arrayEl1/arrayEl2/…?dictKey=dictVal&…

The first command to a given class will construct it, passing the reference to our UIWebView to it as a constructor argument. All command classes now inherit from a new class called PhoneGapCommand, which stores the webview as an instance property.

So then the first, and all subsequent commands, are invoked with two parameters:

1. (NSMutableArray*)arguments
   This is a list of arguments passed on the path component of the URI. They’re URL decoded for you, so any %-encoded characters will be expanded for you.
2. (NSMutableDictionary*)options
   This gives you a dictionary / hash of the query string component of the URI. This is always passed, but if a command doesn’t supply a query string, the dictionary will be empty.

Calls from within JavaScript will take the first hash (object in JavaScript notation) it sees and will use that as the query string. All other arguments need to be strings / numbers, or else they’ll be dropped. This means you can pass your options hash as the first, or even the last argument in a PhoneGap.exec call.

The bulk of this code is almost done, so I’m excited to hear what people think about this. I’m just getting the existing commands working with this model before pushing back out to Git, at which point I’ll continue on and implement native UI toolbars / tabbars.

Update: I’ve updated my branch on Github with my latest changes. I think they’re great, but there are still some changes that need to be made. I got most of the API working, except for contacts. But since they weren’t working so hot to begin with, and someone else has stepped up to the plate to improve Contacts, I’ll let him merge his updates in to my new code. Next up: native UI controls!

I’ve been working on some pretty fun changes to PhoneGap recently, which hopefully will be merged into the main branch soon. (Brock? Any word on that? It’s now 12 days, and counting) In my branch of PhoneGap I added console logging support, I implemented queueing of commands so they don’t walk over each other, and finally (and perhaps more importantly) improved the JavaScript build system and infrastructure.

PhoneGap’s JavaScript Structure

PhoneGap is broken up into several different .js files, each of which implements a part of the PhoneGap API. And with recent changes to PhoneGap’s Objective-C code, the implementations of those commands are divided nicely into their own separate classes. Additionally, there’s platform-specific implementation hooks of those APIs which make the necessary calls in to the native code that implements those commands. At build time, a Rakefile is used to compile these together into one single “phonegap.js” file that can be included into your application.

But in the main branch currently there’s a number of bugs that prevents this system from working. The JavaScript files were being loaded in a bad order, causing prototype methods to be overwritten instead of extended.

I’ve hacked something together to improve on this, but this is really just a stop-gap measure. Really what should happen is an actual JavaScript framework should be adopted to help with class loading, extending classes, and implementing interfaces.

JavaScript Frameworks FTW

I’m a big fan of MooTools, so most of my day-to-day web work is in that framework. But really, most libraries solve the basic problem of “Here’s a base class, I want to either add to it, or subclass it to add more behaviour”. You never know how much you rely on something like that until you have to do without.

I found myself in the uncomfortable position of having to implement prototype-based inheritance by hand, and not in the fun way. This brings me to the main reason for this post, besides the subtle prod to Brock.

I want to see a client-side library that works well for light-weight apps, but still provides capabilities to extend classes, find elements using CSS selectors, provide helper functions for performing CSS-based animations, and provide event binding and closure-wrapping support.

I started toying with JQTouch, and while it’s certainly intriguing, it doesn’t solve some things just yet.

1. It’s still based on the stock jQuery, which is still pretty large, weighing in at 56KB
2. jQuery’s event object doesn’t support any of the iPhone’s touch and rotate/scale event properties. You can get at it by saying “event.context.“, but at that point why bother? The native event object is just fine.
   
3. It doesn’t address some basic issues I have such as function binding

So far I’ve managed to resolve my above issues with PhoneGap’s JavaScript API for the time being, but long term I think there’s some definite needs for the iPhone platform in general. We need to lose the platform-independant thinking of the standard frameworks (“Am I in IE? Am I in Opera?” needs to go). We need to have something that improves upon the already excellent CSS-based animation support of WebKit, and provide more abstract behaviours. And finally, we need to provide capabilities that let us define class-based applications with rich event and callback binding support.

The reason we’re developing applications under PhoneGap is because we want to build apps faster than we could if we developed in native Objective-C. So we need to have a JavaScript library that doesn’t get in our way, and actively solves the problems with JavaScript that WebKit doesn’t already solve.