Comparison between Corona, Phonegap, Titanium

Answer 1

I registered with stackoverflow just for the purpose of commenting on the mostly voted answer on top. The bad thing is stackoverflow does not allow new members to post comments. So I have to make this comment more look like an answer.

Rory Blyth's answer contains some valid points about the two javascript mobile frameworks. However, his key points are incorrect. The truth is that Titanium and PhoneGap are more similar than different. They both expose mobile phone functions through a set of javascript APIs, and the application's logic (html, css, javascript) runs inside a native WebView control.

1. PhoneGap is not just a native wrapper of a web app. Through the PhoneGap javascript APIs, the "web app" has access to the mobile phone functions such as Geolocation, Accelerometer Camera, Contacts, Database, File system, etc. Basically any function that the mobile phone SDK provides can be "bridged" to the javascript world. On the other hand, a normal web app that runs on the mobile web browser does not have access to most of these functions (security being the primary reason). Therefore, a PhoneGap app is more of a mobile app than a web app. You can certainly use PhoneGap to wrap a web app that does not use any PhoneGap APIs at all, but that is not what PhoneGap was created for.

2. Titanium does NOT compile your html, css or javascript code into "native bits". They are packaged as resources to the executable bundle, much like an embedded image file. When the application runs, these resources are loaded into a UIWebView control and run there (as javascript, not native bits, of course). There is no such thing as a javascript-to-native-code (or to-objective-c) compiler. This is done the same way in PhoneGap as well. From architectural standpoint, these two frameworks are very similar.

Now, are they any different? Yes. First, Titanium appears to be more feature rich than PhoneGap by bridging more mobile phone functions to javascript. Most noticeably, PhoneGap does not expose many (if any) native UI components to javascript. Titanium, on the other hand, has a comprehensive UI APIs that can be called in javascript to create and control all kinds of native UI controls. Utilizaing these UI APIs, a Titanium app can look more "native" than a PhoneGap app. Second, PhoneGap supports more mobile phone platforms than Titanium does. PhoneGap APIs are more generic and can be used on different platforms such as iPhone, Android, Blackberry, Symbian, etc. Titanium is primarily targeting iPhone and Android at least for now. Some of its APIs are platform specific (like the iPhone UI APIs). The use of these APIs will reduce the cross-platform capability of your application.

So, if your concern for your app is to make it more "native" looking, Titanium is a better choice. If you want to be able to "port" your app to another platform more easily, PhoneGap will be better.

Updated 8/13/2010: Link to a Titanium employee's answer to Mickey's question.

Updated 12/04/2010: I decided to give this post an annual review to keep its information current. Many things have changes in a year that made some of the information in the initial post outdated.

The biggest change came from Titanium. Earlier this year, Appcelerator released Titanium 1.0, which departed drastically from its previous versions from the architectural standpoint. In 1.0, the UIWebView control is no longer in use. Instead, you call Titanium APIs for any UI functions. This change means a couple things:

1. Your app UI becomes completely native. There is no more web UI in your app since the native Titanium APIs take over control of all your UI needs. Titanium deserves a lot of credit by pioneering on the "Cross-Platform Native UI" frontier. It gives programmers who prefer the look and feel of native UI but dislike the official programming language an alternative.

2. You won't be able to use HTML or CSS in your app, as the web view is gone. (Note: you can still create web view in Titanium. But there are few Titanium features that you can take advantage of in the web view.)Titanium Q&A: What happened to HTML & CSS?

3. You won't be able to use popular JS libraries such as JQuery that assume the existence of an DOM object. You continue to use JavaScript as your coding language. But that is pretty much the only web technology you can utilize if you come to Titanium 1.0 as a web programmer.

Titanium video: What is new in Titanium 1.0.

Now, does Titanium 1.0 compile your JavaScript into "native bits"? No. Appcelerator finally came clean on this issue with this developer blog:Titanium Guides Project: JS Environment. We programmers are more genuine people than those in the Marketing department, aren't we? :-)

Move on to PhoneGap. There are not many new things to say about PhoneGap. My perception is that PhoneGap development was not very active until IBM jumped on board later this year. Some people even argued that IBM is contributing more code to PhoneGap than Nitobi is. That being true or not, it is good to know that PhoneGap is being active developed.

PhoneGap continues to base itself on web technologies, namely HTML, CSS and JavaScript. It does not look like PhoneGap has any plan to bridge native UI features to JavaScript as Titanium is doing. While Web UI still lags behind native UI on performance and native look and feel, such gap is being rapidly closed. There are two trends in web technologies that ensure bright feature to mobile web UI in terms of performance:

1. JavaScript engine moving from an interpreter to a virtual machine. JavaScript is JIT compiled into native code for faster execution. Safari JS engine: SquirrelFish Extreme

2. Web page rendering moving from relying on CPU to using GPU acceleration. Graphic intensive tasks such as page transition and 3D animation become a lot smoother with the help of hardware acceleration. GPU Accelerated Compositing in Chrome

Such improvements that are originated from desktop browsers are being delivered to mobile browsers quickly. In fact, since iOS 3.2 and Android 2.0, the mobile web view control has become much more performing and HTML5 friendly. The future of mobile web is so promising that it has attracted a big kid to town: JQuery has recently announced its mobile web framework. With JQuery Mobile providing UI gadgets, and PhoneGap providing phone features, they two combined creates a perfect mobile web platform in my opinion.

I should also mention Sencha Touch as another mobile web UI gadget framework. Sencha Touch version 1.0 was recently released under a dual licensing model that includes GPLv3. Sencha Touch works well with PhoneGap just as JQuery Mobile does.

If you are a GWT programmer(like me), you may want to check out GWT Mobile, an open source project for creating mobile web apps with GWT. It includes a PhoneGap GWT wrapper that enables the use of PhoneGap in GWT.

Answer 2

I have been working with Titanium for over a week now and feel like I have a good feel about its weakness.

1) If you hoping you use the same code on multiple platforms good luck! You'll see something like backgroundGradient and be amazed until you find out android version doesn't support it. Then have to revert to using a gradient image, might as well use it for both versions to make the code easier right?

2) A lot of weird behaviors, on the Titanium android sdk you need to understand what a "heavy" window is just to get the back button to work, or even better orientation event tracking. This isn't how the android platform really is, its just how Titanium tries to make their API work.

3) Your thrown in the dark, Things will crash and you have to start to comment code and then when you find it, never use it. There are certain obvious bugs, like orientation and percents on android that have been a problem for over six months.

4) Bugs .... there are a lot of bugs and they will be reported, sit around for months, get fixed in a few days. I am surprised they even are planning to release a black berry mobile sdk when there are so many other problems with android.

5) Titanium Iphone versus Titanium Android javascript engines are completely different. On android version you can download remote javascript files, include and use libraries like mootools, jquery and so on. I was in heaven when I found this out because I didn't have to keep compiling my android app. The android apk installation process takes so long! Iphone none of that is possible, also the iphone version has a much faster javascript engine.

If you stay away from a lot of the native UI parts, i.e instead use setInterval to detect orientation changes, sticking with gradient images, forget about the back button, build your own animations, forget window header, toolbars, and dashboard. You really can make an api that works on both that doesn't require of lot of rewriting. But at that points its just as sluggish as a webapp.

So is it worth it? After all the pain, its worth every minute. You can abstract the logic and just build different UI for each rather then if elseing everywhere. Titanium lets you make fluid applications, that feel fast. You lose the powerful layout abilities of each platform but if you think simple, things can get done under a single language.

Why not a web app? On entry level market android phones its horribly slow to generate a webview and consumes a lot of memory you could be using to do more complex logic.