All you need to know Accessibility | iOS SDK | Swift

Why does Accessibility matter?

First thing first, it always feels good to know that even if your work is small but it’s making a huge difference in someone’s life. 🙂 There are millions of smartphone users all around the world with some sort of disability. Enabling accessibility into the software system ease them in interacting with it.

And on the other hand, if you’re working for any government agency you have to implement it because of 508 compliance (which says that any technology or software product must be accessible to all users).

Accessibility domains?

– Vision: a vision challenge that makes focusing difficult, color blindness or total blind.
– Hearing: difficulty hearing sound, partial hearing loss or maybe deaf.
– Physical and motor skills: difficulty when it comes to tapping the interface or holding a device.
– Learning and Literacy: hard to understand a complex user interface or hard to remember a sequence of step to do a certain task.

Image from Apple.

What is VoiceOver?

A screen reading tool that helps the user to interact with the application without seeing the screen. The feature is designed for those who have vision problems. Navigate to Settings/Accessibility/VoiceOver.

VoiceOver: Gestures?

Enable the VoiceOver to try this out.
– Single tap: Tap anywhere, VoiceOver will start speaking information as per the accessibility attributes (find more later).
– Swipe right or left: Try swipe right/left VoiceOver will navigate you through all items on the screen while reading them aloud. Right for forward/down and Left for reverse/up.
-Double Tap: is to tap on a selected item.
– Single swipe down: is to spell out the focused item.
– Three finger swipe: For page views to navigate forwards or backward

Accessibility attributes?

Core attributes that VoiceOver will use to provide information to the user.
– Label: way to identify the view (like settings button, profile image) VoiceOver will speak the same when the item will be selected.
– Traits: way to identify the element state, usage or behaviour (like a button is selected.) 
– Hint: way to describe the action of an element (like Go to detail).
– Frame: frame of the element within the screen.
– Value: The value of element like a slider bar.
– AccessibilityLanguage: The language code that the element label value, hint should be spoken. 

How to debug accessibility attributes?

Accessibility inspector is a tool given by Apple to debug your app (Navigate to Xcode/Open Developer Tool/Accessibility Inspector). Where developer can choose the target, enable the pointer to debug the view.

Accessibility Notification?

Animation or layout changes are a visual feedback to the user as a response of the action taken, Use announcements notification to provide an update (other options are layoutChanged, screenChanged delegates).

Target Touch Size?

As per Apple human interface guidelines it is recommended to maintain a tappable area of 44x44pt (minimum) for all controls in the application.

What is Dynamic Type?

Functionality that allows the users to dynamically adjust the size of text, images (choose their preferred text size). iOS app will adopt the text/image size as per user preference. (Apple Developer documentation)

Setup Smart Invert Colors?

Need to set `accessibilityIgnoresInvertColors` property to enable or prevent a control from inverting it’s colours. (Navigate to Setting/General/Accessibility/Display Accommodations/Invert Colors).

Thanks for reading this.

Quick Tips To Support Dark Mode In Your iOS App | iOS 13

All you need to know about Dark Mode on iOS 13

Overview? With iOS 13 and above people can adopt a dark appearance where Apple docs says user can use settings to make their devices automatically switch to dark mode when ambient is low and this will help you to put focus on your content.

Development Environment? As as iOS developer you’ve to use Xcode 11 with iOS 13 SDK and above, iOS will automatically update system controls such as switches, collection-views etc. If you are migrating your existing app to dark in that case you will have to adapt the colours. 

How to define colours for each mode?

System Colours? iOS 13 SDK includes new system colours so if you adapt these system colours your app will automatically support dark and light mode, You can use it via Storyboard as well as programmatically (Some example below)

Custom Colors? Yes it’s strongly recommended by Apple that use system colours to provide better UX and also to make sure the consistency across apps but using the asset you can define you colour choices. Once you define iOS will take care everything for you.

How to define Image for each mode?

Using the Assets you can specify which image you want to use for dark VS any other mode and just define the image and let iOS take care for you. 

How to detect dark mode programmatically?

On Load Detection? We can use overrideUserInterfaceStyle to check which mode is currently running on user device (Just make sure, this property only available on iOS 13 and above)

Runtime Detection? Can use traitCollectionDidChange to observe the changes, It is important to remember that trait-collection may be called for other trait changes (such as device rotation)

Set Dark Mode for Specific Screen? Yes you can, this property overrideUserInterfaceStyle is available for you to use (only iOS 13 and above)

How to support WKWebView?
Just need to create variable for the color and need to handle this in CSS.

:root {
    color-scheme: light dark;
        --h1-color: #333;
        --header-bg-clr: #FFF1FF;
        --header-txt-clr: white;
    }
    @media (prefers-color-scheme: dark) {
    :root {
        color-scheme: light dark;
        --h1-color: #333;
        --header-bg-clr: #FFF1FF;
        --header-txt-clr: white;
        }
    }

body { }
h1 { color: var(--h1-color); }
.header {
    background-color: var (--header-bg-clr);
    color: var(--header-txt-clr);
}

After Integrating this change you can use Safari to test (First you need to enable the developer menu option in Sarafi, Preferences, Advanced). Open wen inspector (using Command + Options + I) and you will see this screen with the option to toggle light/dark mode.

Swift 5 ABI Stability why matters?

Swift is fast, safe and expressive language to code with great full stack potential and community support. According to Apple, it’s 2.6 times faster than Objective C (As a Swift Developer I agree on this too 🙌). It’s 6th most loved language on StackOverflow.

ABI Background
As a developer, I hope sometimes you also felt that Swift is not mature enough as every year major changes are being introduced. One of the key problems articulated by a lot of developers is “Lack of backward compatibility” and you have to choose one Swift version for your Xcode projects (Version lock). Resulting in with a new Swift release you have to make changes in your existing code.

What is ABI?
ABI stands for Application Binary Interface. During runtime, Swift program interacts with other libraries through ABI (low-level set of protocols for memory representation, function calls, and access).
So when I say ABI not stable it means that each binary is building its own version of Swift Dynamic Library inside it. Now the Swift 5 is ABI Stable which means if I build two apps, one using Swift 5.0 and another using Swift 5.2, both will use Swift ABI embedded in the iOS Operating System.

Why ABI Stability matters a lot?

  1. Compatibility: which means new compilers can compile your old Swift code which means no more migration pain.
  2. Bundle Size: It will reduce the build size because of no Swift standard Library in your Framework folder.
  3. Binary framework and runtime compatibility which enables the framework distribution as a binary which will work across multiple Swift versions.

Conclusion: Swift is the future for Apple ecosystem and now it’s ABI stable which means, in other words, it is like write once and use everywhere.

Reference:
https://swift.org/about/
https://github.com/apple/swift/blob/master/docs/ABIStabilityManifesto.md

Error: WKWebView before iOS 11.0 (NSCoding Support was broken in the previous version)

Important
Starting in iOS 8.0 and OS X 10.10, use WKWebView to add web content to your app. Do not use UIWebView or WebView.

WebKit was introduced in iOS 8 but it was released with an error which caused in a runtime crash, If you are using Xcode 9/10, your project configuration support less than iOS 11 and if you are trying to add WKWebView using interface builder. Xcode immediately shows a compile-time error.

WKWebView before iOS 11.0 (NSCoding Support was broken in the previous version)

Although WKWebView was introduced in iOS 8, there was a bug in –[WKWebView initWithCoder:] that was only fixed in iOS 11.

Resolution is you must add WKWebView through code (Only if you are supporting below iOS 11). That actually sounds strange.

Another solution is to change the Interface Builder Document Builds for the option to iOS 11 and later (If you’re migrating from older target to iOS 11 and still getting the same error).

Why use WKWebView, To use native Safari Javascript optimization. Means it loads web page much faster than UIWebView with less memory usage. 

What is the difference between setNeedsLayout, layoutIfNeeded and layoutSubviews? Quick Notes.

Screen Shot 2018-06-06 at 9.50.17 AM

When the user taps an on App icon, iOS creates an instance of UIApplication which runs on the main thread. This main thread processes all UI events such as touch, location updates etc.

After app launched successfully, it becomes available for the user to do interactions with it and every single interaction which known as an event is processed in a FIFO manner.

Now while events are being processed there may come some UI update requests which aren’t get fulfilled immediately. Instead, the system waits until the existing process finishes and the next redraw cycle comes. There is a periodic interval between the event processing and UI layout handling. The setLayoutNeeded() and layoutIfNeeded are two UIView’s methods here to ask the system for updating the view with new changes.

The setNeedsLayout() tells the system that you want the view and all it’s subviews to be redrawn in the update cycle.

Here is What Apple’s doc says on this, “Call this method on your application main thread when you want to adjust the layout of a view’s subviews. Note that it returns immediately (Async call) because it does not force an update, it waits for the next update cycle”.

Whereas layoutIfNeeded() is an async call which tells the system that you want the view and it’s subviews to be redrawn immediately without waiting for the next update cycle.

UIView have one more method named layoutSubviews() which you can use for your own implementation to set the frame of your view directly by overriding it. And since it’s default implementation uses the constraints you have given to determine it’s size and positions to get the frame, you should override it unless autoresizing and constraint behavior is not working for you as expected.

In short use setNeedsLayout(), if you are okay with the system to update it in the next upcoming update cycle and use layoutIfNeeded() if you want it to be updated immediately.

Thanks for reading.

Swift | Open source projects for learning and developers to follow on twitter

Screen Shot 2018-10-05 at 10.26.35 AM

Announced in 2014, the Swift programming language has quickly become one of the fastest growing languages in history. Swift makes it easy to write software that is incredibly fast and safe by design.

Blog for developers to highlight, top 10 trending open source to learn.

  1. MessageViewController A SlackViewController replacement written in Swift, compatible with iPhone X, iOS12. Created by Ryan Nystrom
  2. Swift interpreter for Pascal language (Inspired from Ruslan’s Blog). Created by Igor Kulman
  3. CollectionViewSlantedLayout subclass of the UICollectionViewLayout allowing the display of slanted cells in a UICollectionView.Created by Yassir Barchi
  4. Mint Package manager that installs and runs Swift command line tools, created by Yonas Kolb
  5. CryptoSwift Collection of standard and secure cryptographic algorithms implemented in Swift. Created by Marcin Krzyzanowski
  6. CocoaDebug Debugger tools for iOS supports Swift and Objective C, created by CocoaDebug
  7. iOS-Depth-Sampler Examples of Depth APIs in iOS, created by Shuichi Tsutsumi
  8. Universal Link Testing  It fetches and parses apple-app-site-association file for you to quickly check whether Universal Links are working. created by Ethan Huang
  9. Swift Syntax Set of Swift bindings for the libSyntax library. It allows for Swift tools to parse, inspect, generate, and transform Swift source code. Created by Apple
  10. WhatsNewKit Showcase your awesome new app features, Created by Sven Tiigi

 

Thanks for reading!

Swift Keynotes: classes & structs

  • Structs are the value type.

Screen Shot 2018-07-16 at 4.52.45 PM.png

  • Classes are the reference type.

Screen Shot 2018-07-16 at 4.51.19 PM.png

  • Properties of a constant instance of the struct are immutable because struct’s instance own the whole object and by declaring it as a constant means the whole object itself will be immutable.

Screen Shot 2018-07-16 at 4.59.08 PM.png

  • Properties of a constant instance of the class are mutable as class’s instance owns the object’s reference thus by declaring it as a constant only means that the further reference assignment can’t be done.

Screen Shot 2018-07-16 at 5.01.29 PM.png

  • Structs are blessed with default member-wise initializer but classes are not.

Screen Shot 2018-07-16 at 4.02.52 PM.png

  • Structs are preferable when they are small and copyable.
  • With Structs, there is much less need to worry about memory leaks or multiple threads racing to access/modify a single instance of a variable.
  • Since struct instances are allocated on the stack, and class instances are allocated on the heap, structs can sometimes be drastically faster (but it still depends on how many values you’re storing and the size/structure.)
  • In a multi-threaded environment, for instance, with a database connection that’s opened in a different thread, structs are safer. They can be copied from one thread to another thread, without running the risk of a race condition or deadlock. Classes do not have this inherent safety unless they’re deliberately made thread-safe.

Thanks a lot for reading it.