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?

Compatibility: which means new compilers can compile your old Swift code which means no more migration pain.
Bundle Size: It will reduce the build size because of no Swift standard Library in your Framework folder.
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

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.

MessageViewController A SlackViewController replacement written in Swift, compatible with iPhone X, iOS12. Created by Ryan Nystrom
Swift interpreter for Pascal language (Inspired from Ruslan’s Blog). Created by Igor Kulman
CollectionViewSlantedLayout subclass of the UICollectionViewLayout allowing the display of slanted cells in a UICollectionView.Created by Yassir Barchi
Mint Package manager that installs and runs Swift command line tools, created by Yonas Kolb
CryptoSwift Collection of standard and secure cryptographic algorithms implemented in Swift. Created by Marcin Krzyzanowski
CocoaDebug Debugger tools for iOS supports Swift and Objective C, created by CocoaDebug
iOS-Depth-Sampler Examples of Depth APIs in iOS, created by Shuichi Tsutsumi
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
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
WhatsNewKit Showcase your awesome new app features, Created by Sven Tiigi

Thanks for reading!

Swift Keynote: Enumeration

An enumeration defines a common type for a group of related values and enables you to work with those values in a type-safe way within your code.
Or when a property can have its value only out of a defined set, enum is the solution which complimentary provides type-safety and auto-completion at compile time.
Enumerations can define initializers to provide an initial case value; can be extended to expand their functionality beyond their original implementation; can have functions and can conform to protocols to provide standard functionality.
Enums can have nested enums and associated values.

Enums can be recursive: A recursive enumeration is an enumeration that has another instance of the enumeration as the associated value for one or more of the enumeration cases. “Indirect” keyword is used to inform the compiler about recursion.

Each enum case’s rawValue depends upon the raw type taken and if no raw type is not taken than rawValue wouldn’t be available. Swift’s enums don’t bound to use only integer type as a raw type, you can use Strings, Characters or even Floats instead.

Happy Coding!!

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.

WWDC 2018 | Keynote |Quick Notes | 2 mins

Screen Shot 2018-06-06 at 9.55.14 AM.png

“Today is all about Software,” Apple CEO Tim said as he took the stage at WWDC 2018.

It all started with statistics.

20 million iOS developers
500 million weekly app store visits
81% using iOS 11 where only 8% using latest Android
Developers earned 100 million through App Store

Screen Shot 2018-06-06 at 9.50.17 AM.png

iOS

New iOS 12 will be released as a free update, every model back to the 5S will get a performance boost.
ARKit, second generation, which included a lot of cool updates, most interesting is the ability for multiple users to observe and interact with the same environment from different angles.
Apple Screen time, now iOS 12 will tell you how much time you’re spending with your iPhone and which are the apps.
Do not disturb a lot of improvements, while you are sleeping will hide the notification, one step one time notifications.
Photos, with iOS 12 they have revamped it. Allowing more search options driven by AI, share the photos through iMessage.
Siri, it’s handling 10 billion requests per month and now Apple is allowing you to interact with it more, create shortcuts to trigger app features.
Animojis, more personal now. It’s super accurate, face-tracking and tongue tracking capabilities. Surely it will feel you very familiar.
Group FaceTime, now chat with 32 people at once with emoji, sticker, and other effects support.

iOS Apps updates

Stocks, new UI with better performance
Apple News app.
Apple iBooks getting a redesign and a new name.
Voice Memos, iPad getting it for the first time and recording will be now synced to iCloud.

Screen Shot 2018-06-06 at 9.51.04 AM.png

watchOS

So far biggest functions of the Apple iWatch is fitness, now Apple adding more components which let you challenge your friends.

Automatic workout detection using your heart-beats(once you stop working out your heart rate decreases, so it will automatically stop).
Walkie-Talkie, Texting/phone are tough using watch screen so Apple added an instant audio messaging app called walkie-talkie (uses the wifi or cellular to interact with other devices).
Siri on Watch, allow third-party apps to show you more information. Now just lift your wrist and start talking it means no more “Hey Siri”.
Podcasts app is coming on your wrist.