iphone Ipad application UI development strategy

I am beginner and plan to make a Iphone/Ipad application which will receive a questionary xml from restful webservice, parse it, get answers from user..with two buttons(next, back) on screen, as you may guess there will be validation alert messages, display messages..etc..checkboxes, radiobuttons, date pickers depend on questions type.

So what would be the best strategy, to insert if else blocks on user interface and choose the layout for device type while I am developing the application, or first make a working iphone version a开发者_C百科nd convert it to Ipad later on, and would that be easier? what kind of problems should I expect while converting to IPAD..thanks!

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When you create a universal app, you have the option to keep all viewControllers and xib files separate for iPhone and iPad. This is very handy. Alternately, you can check which device the user has and load the correct xib that way, but since the structure of the apps may be quite different, I strongly encourage the latter approach instead.

The ipad has a bigger screen. This is numerous consequences for designing most apps. Also, the ipad has a splitviewcontroller which is quite handy, whereas the iphone tabbarcontroller is better there.

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iPhone and iPad have different UI requirements. Read the apple iOS human interface guidelines, it's very nicely explained in there. You'll also find the answer of what to do if you usually would use radio buttons, because there are no radio buttons on iOS.