What is KVO and KVC IOS?
KVO and KVC or Key-Value Observing and Key-Value Coding are mechanisms originally built and provided by Objective-C that allows us to locate and interact with the underlying properties of a class that inherits NSObject at runtime.
What is difference between KVO and KVC in Swift?
The Other way which is better In this kind of scenarios is (also Apple using this in its libraries a lot) known as KVO(Key Value Observing), which is also directly related to another powerful mechanism called KVC(Key Value Coding). Note: Any property we want to observe for changes must be KeyValueCoding (KVC)complaint.
What is KVO in IOS?
Swift 4 Xcode 9 ios 11. Key-Value Observing, KVO for short, is an important concept of the Cocoa API. It allows objects to be notified when the state of another object changes. That sounds very useful.
What is KVC and KVO give an example of using KVC to set a value?
Inside this method, we can perform any logic for any keyPath. The main disadvantage of this method is that we have to check the change in the values for each key/keyPath. The best example of KVO and KVC is how UserDefaults uses this mechanism to set, change and modify the values.
What is atomic and non atomic in Swift?
Atomic means only one thread accesses the variable (static type). Atomic is thread-safe, but it is slow. Nonatomic means multiple threads access the variable (dynamic type). Nonatomic is thread-unsafe, but it is fast. Follow this answer to receive notifications.
What is KVC in IOS Swift?
According to Apple: Key-value coding is a mechanism for accessing an object’s properties indirectly, using strings to identify properties, rather than through invocation of an accessor method or accessing them directly through instance variables.
What is key and value in coding?
About Key-Value Coding. Key-value coding is a mechanism enabled by the NSKeyValueCoding informal protocol that objects adopt to provide indirect access to their properties. When an object is key-value coding compliant, its properties are addressable via string parameters through a concise, uniform messaging interface.
What is Swift KVO?
Key-value observing is a mechanism that enables an object to be notified directly when a property of another object changes. It is a mode of communication between objects in applications designed in conformance with the Model-View-Controller design pattern.
What is thread safe in Swift?
If different threads accessing some piece of shared state at very specific moments at the same time cannot result in your class ending up in an unexpected/broken state, then your code is thread-safe.
What is threading in Swift?
Multithreading can be defined as the process which facilitates the CPU to create and execute concurrent threads. Typically, a CPU performs one operation at a time.
What is willSet and didSet?
willSet is called just before the value is stored. didSet is called immediately after the new value is stored.
Is didSet called on init?
willSet and didSet observers are not called when a property is first initialized. They are only called when the property’s value is set outside of an initialization context.
What is KVO in Objective-C?
Key Value Observer (KVO) is based on KVC, and can observe the change of a property of another object. KVO allows you to register as an observer of a given object and receive notification when specific properties on that object are changed.
What is GCD in iOS Swift?
Grand Central Dispatch (GCD) is used for managing concurrent operation, it is a low-level API. It was first introduced in iOS 4. The main purpose of Grand Central Dispatch is to manage the heavy tasks in the background.
How do threads work iOS?
A thread is a sequence of instructions that can be executed by a runtime. Each process has at least one thread. In iOS, the primary thread on which the process is started is commonly referred to as the main thread. This is the thread in which all UI elements are created and managed.
What is didSet?
In Swift, didSet and willSet methods act as property observers. willSet runs a piece of code right before a property changes. didSet runs a piece of code right after the property has changed.
What is willSet?
willSet and didSet are the another useful codes for observing the data change of a variable. willSet is called before the data is actually changed and it has a default constant newValue which shows the value that is going to be set.
What is willSet and didSet in Swift?
willSet is called before the data is actually changed and it has a default constant newValue which shows the value that is going to be set. didSet is called right after the data is stored and it has a default constant oldValue which shows the previous value that is overwritten.
What does didSet mean in Swift?
In Swift, you can attach property observers to variables to run code when the variable changes. These property observers are called willSet and didSet. The former runs right before the property changes, and the latter runs right after the changes were made.
What is KVO programming?
Key-value observing provides a mechanism that allows objects to be notified of changes to specific properties of other objects. It is particularly useful for communication between model and controller layers in an application.