Implementing autocompletion OTP field in iOS

Long waiting is over. !! iOS 12 brings Autofill for OTP text field which is close to Android provided a decade back. Previously in iOS we used to toggle between OTP text screen and message inbox. Which was hard to remember and time consuming resulting a bad user experience. Personally, I have been asked from the client/customer couple of times to implement autocompletion for OTP field and took me a lot of time to convey that it is not possible in iOS.

Why Autofill was not possible previously?

We all know that Apple gives at most care for user privacy. When we see iOS architecture, each individual app is like a separate island. There is no inter-app bridge between apps (exception for Keychain and URLSchemes APIs which gives very limited scope). Thus we cannot read message content from inbox.

Where to start Autofilling?

First of all, the target SMS need to have the OTP Code with prefix string "Code" or "Passcode"on its message content. Beware of OTP code accepted only if it has no space and works only with system provided keyboard. Do not expect this feature works with custom keyboard.

Now from the application side, make sure that device running in iOS 12 and set text field content type to `.OneTimeCode`.

This can be also achieved via storyboard. Just select UITextField in storyboard/XIB and click on Attribute Inspector. Go to text input trait, For Content Type, choose "One Time Code" from drop down. Keyboard Type doesn't matter.

That's all about implementations...! Now as given in the first diagram, as soon as a SMS with OTP code landed in the message inbox, we will see the same in the tool bar of the Keyboard. All we need to tap the code for autofill OTP field.

Read further from Apple's complete documentation .

Animating label text update - choosing a better way

Recently I published a countdown app . At one point of development - I have to show a timer on a UILabel which ticks on each seconds. As usual I started setting text to a label object - self .timerLabel.text = someString Easy piece of cake right !? But wait ... it won't take much user attention when timer ticks on every seconds. So I decided to make use of a simple animation while label gets text update. I found there are dozens of ways to animate a label. In this short article, I listed 3 best way you can animate text on a label. ( Spoiler Alert 👀- I decided to go with 3rd option) 1. Fade In - Fade out animation : CATransition class has got transition type `fade`. With timing function of CATransition - I was able to see the below result. let animation: CATransition = CATransition () animation.timingFunction = CAMediaTimingFunction (name: CAMediaTimingFunctionName .easeInEaseOut) animation.type = CATransitionType .fade animation.subtype = CATransitionSubtype .

Prevent Navigationbar or Tabbar overlapping Subview - solved for Card view

Recently, I started with a Card view added as a subview of UIView in a view-controller. When a view controller created along subviews, it tends to use entire screen bounds and also slips behind Tab bar or Navigation bar. In my current situation, it's second case. Casually new iOS developers will write a patch by additional value for coordinate y and subtracting bar height from its size. A lot of them posted in SO threads too : How to prevent UINavigationBar from covering top of view? View got hidden below UINavigationBar iOS 7 Navigation Bar covers some part of view at Top So, how I got solved ? self.edgesForExtendedLayout = [] This will avoid all subviews in a view controller get behind any bars. Read full apple documentation on here. Full Source code below : //Simple view controller where its view layed-out as a card. class WidgetCardViewController : UIViewController { var containerView = UIView () //MARK:- View Controller Life Cycle ov

UICollectionViewCell shows with wrong size on First time - Solved

We commonly use Collection view where its cell size calculated run time. The flow layout delegate is responsible to return individual cell sizes. BUT in most of the cases, delegate method `collectionView: layout sizeForItem:` expects cell size too early. Before generating actual cell size. extension YourViewController : UICollectionViewDelegateFlowLayout { func collectionView ( _ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize { return CGSize (width: externalWidth, height: externalHeight) } } For instance, if a cell size depends on external view and its frame is not yet ready - results with wrong (or outdated) cell size. Typically happens for the first time view controller laid out all views. You can find similar queries in StackOverflow community : Collection view sizeForItemNotWorking UICollectionViewCell content wrong size on first load How to refresh UICollection

Printing Staircase Pattern : Swift coding challenge

In this post, we can try interesting pattern printing challenge in Swift. The problem statement goes like this " Print a staircase of given size 'n'. Make sure that its base and height are both equal to n, and the image is drawn only using `#` symbols and spaces. The last line is not preceded by any spaces." Expected Output : # ## ### #### ##### ###### Working solution: func makePatternOf ( _ size : Int ) { var str = "" // 1 for index in ( 0 ..< size ) { let stop = size -index-1; // 2 for _ in 0 ..< stop { str. append ( " " ) ; } // 3 for _ in 0 .. . index { str. append ( "#" ) ; } print ( str ) str = "" } } makePatternOf ( 6 ) Loop to visit every row of stair case. Loop for appe

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