Complex applications generally need to be created with the native environment.
Simple applications can be created with cross platform tools like Titanium and PhoneGap:
- http://www.appcelerator.com/
- http://www.phonegap.com/
@Fraggle (see comment)
I have quite some experience with Appcelerator Titanium. The choice for native v.s. cross-plafrom completely depends on the kind of application you need and your knowledge. General considerations:
- Can the application be created with web technologies like HTML, CSS and JavaScript?
- What language / environment do I know the best (native vs web technologies)?
- How much time and money can I spend?
- Do I really need cross-platform compatibility?
Most mobile phone applications only provide an easy interface for internet services like news updates, traffic info, social media and video. Those applications can be easily written with web technologies. Therefor most mobile applications can be written with tools like Titanium. The great thing about Titanium: Get the native experience on multiple devices while only maintaining one code-base. Cheap way of developing cross-platform applications.
Many developers use Titanium because they don't know the native language (objective-C / java), but they have extensive knowledge about web technologies. This way they can create pretty nice applications without learning new languages. Titanium is actually used for many non-cross-platform applications.
Complex graphics, device specific tools and complex interfaces still require the native environment.
Native applications will always perform better and use device specific features, but do you really need that degree of perfection? Yes, develop native applications for every device. No, simply create one cross-platform application.
Check this page to see what Titanium can do:
http://www.appcelerator.com/showcase/applications-showcase/