If you want to become a developer of iOS from scratch, there are several skills you need to acquire. Skills specifically related to iOS and Cocoa Touch Marcos. Apart from these skills, you should also have knowledge about object-oriented principles, measures to control use of the source and language as Swift or Objective-C is required to carry out the development of IOS. Once you are able to create an application for IOS from the beginning, you can easily get work as a developer of IOS.
The user interface must be understood images, text views, labels, buttons and other controls that are listed in the code and in storyboards.
By using Automatic design, you will need to ensure that the views to be where it should be in screen sizes and orientations.
user interactions have to be maintained using the buttons, switches, table views, sliders and other controls.
The IOS application should also have several types of navigation controllers tab bar, page view controllers and navigation controllers and even combinations thereof.
The deep understanding of the concept of delegation. This may include some examples of IOS API that makes use of the concept. From it, you should be able to create and use their own delegate API.
Knowledge of these skills will certainly help to qualify for employment as an entry level IOS developer. It also initiates a learning process that helps to recover gain knowledge about other frameworks and technologies required for the job.