THe Xcode framework has MVC patterns similar to anywhere else so that different views can be navigated through controller actions. The actions can be invoked from the controls on the UI so this follows a well known pattern. Additionally the model can keep track of all object states. It can be persisted locally on the device if SQLLite provider is used. Otherwise, model can also be persisted as files. Cloud based storage for model could be possible via iCloud Service.
The controls can be dragged and dropped from the toolbox to the emulator. This is a very visual designer way of describing the page. And we can set various properties on the page as well. In addition, the same controls can be dragged to the controller to show what is associated with the actions. The Objective C framework let us use the objects directly. For example, a button can be dragged to the controller to describe what action is associated with it. The simulator to code connection is tracked with a line so it's easy to follow and to drag and drop.
In our case where we want to design a user interface to make web requests and responses, we could rely on the ASIHttpRequest library. That code can directly be included in your application and it makes GET and POST request easier than the native support. The form on our user interface can help with making the request while the response will simply be echoed out to the screen. This single page interface is sufficient for this kind of a request response view.  This doesn't mean we can't add more pages. Different pages can be added via different views and workflows to navigate between the views can be specified through the controller. The framework allows you to run the app in universal mode so that it can be used directly with both iPhone and iPad without customizing for any one. In addition, there are ways to sign and package your application so that it can be published to the app store.
As a way to test the application with full web request and response, there is a test project created with the source. This can be used to incrementally add features via test driven development. It is nevertheless important to have tests run on the code prior to publish even if this is strictly not followed. At the time of publish, while the code may not change, there may be additional changes coming in via picking out images and themes for the application. Hence, trying out the app from the app store will surely be recommended.