Apple launched its new native language called "Swift" back in June 2014 for creating apps for iPhone, iPod, Apple Watch and other apple devices. Apple promised that it is a lot faster and simpler than Objective-C. In this article, we will discuss how to convert a legacy iOS app written in Objective-C language to Swift without rewriting all the code from scratch.
To understand this article, you should be familiar with both Swift and Objective-C. Here is a quick getting started to Swift article. Another guide for Swift (https://developer.apple.com/swift/) is there to help you get going.