iOS
- Getting started with iOS
- Learn Tutorial
- Awesome Book
- Awesome Community
- Awesome Course
- Awesome Tutorial
- Awesome YouTube
- 3D Touch
- Accessibility
- ADDING A SWIFT BRIDGING HEADER
- AFNetworking
- AirDrop
- AirPrint tutorial in iOS
- Alamofire
- App Submission Process
- App Transport Security (ATS)
- App wide operations
- AppDelegate
- Application rating/review request
- ARC (Automatic Reference Counting)
- attributedText in UILabel
- Auto Layout
- AVPlayer and AVPlayerViewController
- AVSpeechSynthesizer
- AWS SDK
- Background Modes
- Background Modes and Events
- Basic text file I/O
- Block
- CAAnimation
- Cache online images
- CAGradientLayer
- CALayer
- Carthage iOS Setup
- CAShapeLayer
- Categories
- CGContext Reference
- Chain Blocks in a Queue (with MKBlockQueue)
- Change Status Bar Color
- Checking for Network Connectivity
- Checking iOS version
- CLLocation
- CloudKit
- Codable
- Code signing
- Concurrency
- Configure Beacons with CoreBluetooth
- Contacts Framework
- Content Hugging/Content Compression in Autolayout
- Convert HTML to NSAttributed string and vice verse
- Convert NSAttributedString to UIImage
- Core Data
- Core Graphics
- Core Location
- Core Motion
- Core SpotLight in iOS
- CoreImage Filters
- Create .ipa File to upload on appstore with Applicationloader
- Create a Custom framework in iOS
- Create a video from images
- Creating an App ID
- CTCallCenter
- Custom fonts
- Custom Keyboard
- Custom methods of selection of UITableViewCells
- Custom methods of selection of UITableViewCells
- Custom UITextField
- Custom UIViews from XIB files
- Cut a UIImage into a circle
- CydiaSubstrate tweak
- Debugging Crashes
- Deep Linking in iOS
- DispatchGroup
- Dynamic Type
- Dynamically updating a UIStackView
- EventKit
- Extension for rich Push Notification - iOS 10.
- Face Detection Using CoreImage/OpenCV
- FacebookSDK
- Fastlane
- FCM Messaging in Swift
- FileHandle
- GameCenter Leaderboards
- GameplayKit
- GCD (Grand Central Dispatch)
- Graph (Coreplot)
- Guideline to choose best iOS Architecture Patterns
- Handle Multiple Environment using Macro
- Handling URL Schemes
- Healthkit
- iBeacon
- IBOutlets
- In-App Purchase
- Initialization idioms
- iOS - Implementation of XMPP with Robbie Hanson framework
- iOS 10 Speech Recognition API
- iOS Google Places API
- iOS TTS
- Key Value Coding-Key Value Observation
- Keychain
- Load images async
- Localization
- Make selective UIView corners rounded
- Managing the Keyboard
- MKDistanceFormatter
- MKMapView
- ModelPresentationStyles
- MPMediaPickerDelegate
- MPVolumeView
- Multicast Delegates
- MVP Architecture
- MVVM
- MyLayout
- Navigation Bar
- NSArray
- NSAttributedString
- NSBundle
- NSData
- NSDate
- NSHTTPCookieStorage
- NSInvocation
- NSNotificationCenter
- NSPredicate
- NSTimer
- NSURL
- NSURLConnection
- NSURLSession
- NSUserActivity
- NSUserDefaults
- Objective-C Associated Objects
- OpenGL
- Passing Data between View Controllers
- Passing Data between View Controllers (with MessageBox-Concept)
- PDF Creation in iOS
- plist iOS
- Profile with Instruments
- Push Notifications
- QR Code Scanner
- Realm
- Resizing UIImage
- Rich Notifications
- Runtime in Objective-C
- Safari Services
- Security
- Segues
- Set View Background
- Simulating Location Using GPX files iOS
- Simulator
- Simulator Builds
- SiriKit
- Size Classes and Adaptivity
- Size Classes and Adaptivity
- SLComposeViewController
- Snapshot of UIView
- SqlCipher integration
- StoreKit
- Storyboard
- Swift and Objective-C interoperability
- Swift: Changing the rootViewController in AppDelegate to present main or login/onboarding flow
- SWRevealViewController
- UI Testing
- UIActivityViewController
- UIAlertController
- UIAppearance
- UIBarButtonItem
- UIBezierPath
- UIButton
- UICollectionView
- UIColor
- UIControl - Event Handling with Blocks
- UIDatePicker
- UIDevice
- UIFeedbackGenerator
- UIFont
- UIGestureRecognizer
- UIImage
- UIImagePickerController
- UIImageView
- UIKit Dynamics
- UIKit Dynamics with UICollectionView
- UILabel
- UILabel text underlining
- UILocalNotification
- UINavigationController
- UIPageViewController
- UIPheonix - easy, flexible, dynamic & highly scalable UI framework
- UIPickerView
- UIRefreshControl TableView
- UIScrollView
- UIScrollView AutoLayout
- UIScrollView with StackView child
- UISearchController
- UISegmentedControl
- UISlider
- UISplitViewController
- UISplitViewController
- UIStackView
- UIStoryboard
- UISwitch
- UITabBarController
- UITableView
- UITableViewCell
- UITableViewController
- UITextField
- UITextField Delegate
- UITextView
- UIView
- UIViewController
- UIWebView
- Universal Links
- Using Image Aseets
- UUID (Universally Unique Identifier)
- WCSessionDelegate
- WKWebView
- Xcode Build & Archive From Command Line
- XCTest framework - Unit Testing
iOS Key Value Coding-Key Value Observation Use of context for KVO Observation
Example
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context
Context is important if you ship your class for others to use.Context lets your class observer verify that its you observer which is being called.
The problem with not passing an observer is, if some one subclass your class and register an observer for the same object,same key and he does not passes a context ,then the super class observer can be called multiple time.
A variable which is unique and internal for your use is a good context.
For more information.
