Question

When I started with IPhone development I preferred using Interface builder for creating views in my application. With time I considered the option of creating the application via code which I really feel comfortable working with.
Now, when I know both ways to create my user interface, I have doubts which way to follow. I keep thinking where to use IB and where to use code. How can I figure out before starting with my application, which way should I create my UI?

Answer 1

There are a number of factors that can influence your choice. It can come down to personal taste, but there are some advantages to using Interface Builder.

The first thing to recognize is that UI design is inherently a visual task. Interface Builder can allow you to create and modify a UI much faster than you can in code. Rather than endlessly tweaking CGRect values in code, then recompiling, testing, and repeating this process, you can instead get direct visual feedback about your changes. This means you can refine and polish the UI much more efficiently, and even test out radically different layouts without too much time or effort.

Another important point is that if you can create and layout a control in Interface Builder, that means there is less code in your view controller. Less code is always a good thing (less bugs, easier to maintain, …).

So I believe you should try to define as much of the layout and properties in Interface Builder as you can. This can be hard for people who prefer “full control” over things. Many years ago, visual GUI editors were renowned for doing the wrong thing, and developers often shunned their use over doing everything by hand. But Interface Builder is pretty good at what it does, and you can easily dive into code when you need to.

The situations where you would create controls purely in code are when you need to dynamically create a number of objects, for example thumbnail buttons for a photo gallery, or if you have custom layout requirements.

For example, if you have a label whose height is dynamic at runtime, and you want to layout a bunch of controls underneath it (taking its height into consideration), that can only be done in code (UPDATE: iOS 6’s Auto-layout can do this now). You can either create and layout everything in code, or you can still create the controls using Interface Builder and just give them arbitrary positions in the XIB which are modified when you lay them out in code. It’s not uncommon to see this in some of my XIBs:

The buttons along the top can be created and layed out fully in IB, but the image views below need their images and positions to be calculated at runtime. So we just give them arbitrary positions in the XIB. Some might find this ugly, but it saves time and effort on writing code to create the image views and set up their properties. Again, less code is a good thing.

Other times you may want to use code is setting certain explicit properties. Let’s say you have an image view which needs to receive touch events because it has some gesture recognizers added to it. You need to set the “User Interaction Enabled” property to TRUE. It can be better to do this in code because the requirement is more visible and you can leave appropriate comments as to why you are setting the property. It’s also harder to ‘lose’ the setting like you can in interface builder if you need to delete and recreate a bunch of views.