Getting started with iOS programming using Swift (Part 1)

I have not been too fond of Objective-C, which was the primary reason for me to stay away from making iOS apps till now. So what changed? Well Apple has done something very interesting recently and that is the introduction of a new programming language i.e. Swift. Swift is awesome, it almost feels like Python, C++ and Objective-C had a baby with some of their good parts in them. So I have been getting to know Swift and it is an awesome language to program in. What I am going to share with this and a series of blog posts are solutions to some problems that i have encounter while i am trying to finish my first iOS app.

The one hurdle that I have encountered while getting started on developing an iOS app is that a majority of the solutions for iOS specific problems provide solutions to them using Objective-C. Which is fair, because Swift has not been around for that long. Anyway let us get started with a few basics,

A few basics

I would highly recommend having a read of this book i.e.  the free book titled Swift Programming Language by Apple.

String and Numbers

var num:String = "123"; //create a string
var val  = num.toInt()!; //convert it to an Int
var value:String = "Concat:\(val)"; ///concat a string with an Integer

Working with WebViews

Say we want to show some HTML content in our app, well one way to do that in an iOS app is by using webViews i.e. UIWebView.  How do we do that? ok lets look at how we can achieve this. When you start a create a new project called HelloWorld, in your project navigator you will see a tree-like structure that shows the linked libraries (if you have any?) followed by 3 folders which will be something like HelloWorld, HelloWorldTests and Products. Now if you have an HTML file called index.html, that you want to display in your app, follow the following steps to do so.

1. Add a WebView object to your storyboard. 
2. Add a reference outlet for that WebView to your ViewController and give it a name,  say webView. If you do not know how to add a reference outlet to your ViewController, you will find this video very helpful.
3. Add your index.html file to your project by right-clicking on the HelloWorld folder in your project navigator and selecting Add Files to HelloWorld. 

Next up is displaying the contents of index.html into your WebView, that can be achieved with the following code.

//get the path to the index.html file
var path = NSBundle.mainBundle().pathForResource("index", ofType: "html");
let url = NSURL(string: path!); //initialise an NSURL with the path to the index.html file
let request = NSURLRequest(URL: url); //add the url in a request
webView.loadRequest(request); //have the UIWebView load the request

This post sheds some more light into dealing with some additional features in iOS 8 for working with HTML content.

How to take in a string and convert it to NSDate

Say we receive a date in a String format from the webView and we want to convert that to a date in Swift. How do we do that? Use the NSDateFormatter and set the NSDateFormatter.dateFormat to a particular type of date format.

e.g.

let start = "1996.07.10 16:08:56"
let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat="yyyy.MM.dd HH:mm:ss";
let startDate:NSDate = dateFormatter.dateFromString(start)!

Some references

I would strongly recommend following this series of blog posts by Jameson Quave. They are very informative and get you started from the pure basics, so you can actually learn something even if you do not come from an iOS development background.