Occasionally we hear the question "Why do you use Titanium as base for your cool Domino To Go framework? Why not using Phonegap?". The quick answer always is: because with Titanium you're able to create real native Apps easily, while with Phonegap you're producing websites that want to look like native Apps.

Nevertheless I was curious what Phonegap really is about, so I spend some time in the last days to dig my way through Phonegap. My leading question was: would it be possible to port Domino To Go to Phonegap?

In theory, this should not be that hard. Domino To Go needs a SQLite database to store data and a filesystem for some simple file operations. Furthermore, it needs an XHR object to do Ajax-HTTP calls. Everything else is pure standard JavaScript and should work instantly on platforms like Phonegap (or HTML5).

Phonegap provides a SQLite database, file operations and the XHR object is part of JavaScript anyway. So I started to play and so far, porting Domino To Go to Phonegap seems to be possible.

Look and feel of Phonegap Apps

Developing a mobile App with Phonegap means to develop the UI with HTML5 and JavaScript. I used jQuery mobile, which allows to develop a basic UI fast and easy. But while I played with my test App, I always thought "this thing does not feel native". The look of buttons, lists and so on is not the very same as in real native Apps. The transitions between "windows" are not the same. In short, the look & feel is not the same.

Maybe I did something wrong. Maybe I overlooked the "make everything look like native"-switch in jQuery mobile. In the end, I only had a couple of days for my experiments.

With Titanium on the other hand, all native controls are used. The App looks & feels like every other native App on the device. From my perspective, this is clearly an advantage for Titanium.

Working with JavaScript in Phonegap Apps

Basically, coding JavaScript in a Phonegap App is not different from coding any other web application, since the Phonegap App on the mobile device is a web application. To access specific features of the device, like the SQLite database or files, Phonegap provides JavaScript APIs.

While working with these device specific JavaScript APIs I came across one major issue I really don't like:  the excessive use of callbacks.

In Phonegap, you cannot do something like this:


var fs = window.requestFileSystem(LocalFileSystem.PERSISTENT);
var f = fs.getFile("somefile.txt");
f.write("some data");


you need to do it like this:


var callback3 = function(writer) {
 writer.write("some data");
}

var callback2 = function(file) {
 f.createWriter(callback3);
}

var callback1 = function(fileSystem) {
 fileSystem.getFile("somefile.txt", callback2);
}

window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, callback1);


You see? Callback calls a callback calls a callback calls another callback. Perhaps I'm not modern enough, or I'm not cool enough, but I don't like this style of coding. And I'm very, very, very sure that every standard Domino developer who knows LotusScript and just made some progress in JavaScript in XPages does not like this style either.

When working with a SQLite database it's the same. You cannot simply get a result set for a SQL query, you need to execute the query and give a callback that gets the result set. I feel this is unnecessary complicated.

Don't get me wrong, there are situations where callbacks really make sense. For example for HTTP requests, because you don't know how long the request will take and you don't want to block the whole App while the request runs. But for small file and database operations, I thinks that callbacks only make the code more complicated.

Is it worth the effort?

As said above, I think porting Domino To Go to Phonegap would be possible. But it would need some creative work to maintain one code base for Titanium and Phonegap while covering the excessive use of callbacks in Phonegap, which is a major difference to Titanium. So is it worth the effort?

At least for iOS and Android, I don't see a reason why to use Phonegap. Coding is more complicated, the UI doesn't look like native Apps and stuff like using an ecrypted SQLite database seems not to be possible with Phonegap. The best argument for supporting Phonegap would be that it is available for Windows Phone and Blackberry.

Your opinion?