iOS Apps iPhone is an operating system created and developed by Apple devices such as iPad, iPhone, iPod Touch, and iWatch. It is the most known and used mobile operating system after Android in the worldwide market. iOS has been extending its support to other Apple devices such as Apple's App Store has more than 2.1 million iOS applications, 1 million of which are native for iPads. These mobile apps have cooperatively been downloaded more than 130 billion times in a day.
Criteria | Result | ||
Type of operating system | Apple proprietary based on Macintosh OS X | ||
OS fragmentation | Tightly integrated with Apple devices | ||
Security | Heightened security guaranteed |
HTTP live streams that have their media encrypted will not be recorded by QuickTime Player on Yosemite while screen recording. These will blackout in the recording.
HTTP live streaming: It sends live and on‐demand audio and video to iPhone, iPad, Mac, Apple TV, and PC with HTTP live streaming (HLS) technology from Apple. Using the same protocol that powers the web, HLS lets us deploy the content using ordinary web servers and content delivery networks. HLS is designed for reliability and dynamically adapts to network conditions by optimizing playback for the available speed of wired and wireless connections.
In addition to the core app behaviors, UIKit provides support for the following features:
State transitions can be responded to state changes in an appropriate way by calling corresponding methods on the app’s delegate object.
For example:
The following features are added in iOS 9:
Assign creates a reference from one object to another without increasing the source’s retain count.
if (_variable != object)
{
[_variable release];
_variable = nil;
_variable = object;
}
Retain creates a reference from one object to another and increases the retain count of the source object.
if (_variable != object)
{
[_variable release];
_variable = nil;
_variable = [object retain];
}
Cocoa | Cocoa Touch | ||
1. Application development environments for OS X | 1. Application development environments for iOS | ||
2. Includes the Foundation and AppKit frameworks | 2. Includes Foundation and UIKit frameworks | ||
3. Used to refer any class/object which is based on the Objective-C runtime & inherits from the root class | 3. Used to refer the application development using any programmatic interface |
Properties specified as atomic always return a fully initialized object. This also happens to be the default state for synthesized properties. But, if you have a property for which you know that retrieving an uninitialized value is not a risk (e.g. if all access to the property is already synchronized via other means), then setting it to nonatomic can give you better performance than atomic.
An App ID is a two-part string used to identify one or more apps from a single development team. The string consists of a Team ID and a bundle ID search string, with a period (.) separating the two parts. The Team ID is supplied by Apple and is unique to a specific development team, while the bundle ID search string is supplied by the developer to match either the bundle ID of a single app or a set of bundle IDs for a group of apps.
The bundle ID defines each App and is specified in Xcode. A single Xcode project can have multiple targets and therefore output multiple apps. A common use case is an app that has both lite/free and pro/full versions or is branded multiple ways.
The three ways to achieve concurrency in iOS are:
The different iOS application states are:
UIKit classes should be used only from an application’s main thread.
UI Automation API is used to automate test procedures. JavaScript test scripts that are written to the UI Automation API simulate user interaction with the application and return log information to the host computer.
An app is said to be in ‘not running’ state in the following cases:
An app enters background state briefly on its way to being suspended.
Objective-C is the primary programming language you use to write software for OS X and iOS. It’s a superset of the C programming language and provides object-oriented capabilities and a dynamic runtime. Objective-C inherits the syntax, primitive types, and flow control statements of C and adds syntax for defining classes and methods. It also adds language-level support for object graph management and object literals while providing dynamic typing and binding, deferring many responsibilities until runtime.
Swift is a new programming language for iOS, OS X, watchOS, and tvOS apps that builds on the best of C and Objective-C, without the constraints of C compatibility. Swift adopts safe programming patterns and adds modern features to make programming easier, more flexible, and more fun. Swift feels familiar to Objective-C developers and is friendly to new programmers.
SpriteKit is a framework for easy development of animated 2D objects.
SceneKit is a framework inherited from OS X that assists with 3D graphics rendering.
SpriteKit, SceneKit, and Metal are expected to power a new generation of mobile games that redefine what iOS devices’ powerful GPUs can offer.
iBeacon.com defines iBeacon as Apple’s technology standard which allows Mobile Apps to listen for signals from beacons in the physical world and react accordingly. iBeacon technology allows Mobile Apps to understand their position on a micro-local scale, and deliver hyper-contextual content to users based on location. The underlying communication technology is Bluetooth Low Energy.
Every time -autorelease is sent to an object, it is added to the inner-most autorelease pool. When the pool is drained, it simply sends -release to all the objects in the pool.
Autorelease pools are a convenience that allows you to defer sending -release until “later”. That “later” can happen in several places, but the most common in Cocoa GUI apps is at the end of the current run loop cycle.
The reuseIdentifier is used to indicate that a cell can be re-used in a UITableView. For example when the cell looks the same, but has different content. The UITableView will maintain an internal cache of UITableViewCell’s with the reuseIdentifier and allow them to be re-used when dequeueReusableCellWithIdentifier: is called. By re-using table cell’s the scroll performance of the tableview is better because new views do not need to be created.
Retaining an object means the retain count increases by one. This means the instance of the object will be kept in memory until it’s retain count drops to zero. The property will store a reference to this instance and will share the same instance with anyone else who retained it too. Copy means the object will be cloned with duplicate values. It is not shared with any one else.
A category is a way of adding additional methods to a class without extending it. It is often used to add a collection of related methods. A common use case is to add additional methods to built in classes in the Cocoa frameworks. For example adding async download methods to the UIImage class.
viewDidLoad is called when the view is loaded, whether from a Xib file, storyboard or programmatically created in loadView. viewDidAppear is called every time the view is presented on the device. Which to use depends on the use case for your data. If the data is fairly static and not likely to change then it can be loaded in viewDidLoad and cached. However if the data changes regularly then using viewDidAppear to load it is better. In both situations, the data should be loaded asynchronously on a background thread to avoid blocking the UI.
This is a very common task in iOS and a good answer here can cover a whole host of knowledge. The important piece of information in the question is that the images are hosted remotely and they may take time to download, therefore when it asks for “considerations”, you should be talking about:
Both are used for sending values and messages to interested parties. A delegate is for one-to-one communication and is a pattern promoted by Apple. In delegation the class raising events will have a property for the delegate and will typically expect it to implement some protocol. The delegating class can then call the _delegate_s protocol methods.
Notification allows a class to broadcast events across the entire application to any interested parties. The broadcasting class doesn't need to know anything about the listeners for this event, therefore notification is very useful in helping to decouple components in an application.
[NSNotificationCenter defaultCenter]
postNotificationName:@"TestNotification"
object:self];
An ARWorldMap object contains a snapshot of all the spatial mapping information that ARKit uses to locate the user’s device in real-world space.
Once the AR world map created from once device is transferred to the other device using P2P connectivity or some other reliable source, the other devices can also have the same AR experience similar to the first device.
To create an ongoing shared AR experience, like placing an AR object, When one user taps in the scene, the app creates an anchor and adds it to the local ARSession, instead of sending the whole map we can serializes that ARAnchor using Data and sends it to other devices in the multipeer session.
Tuples are Temporary container for Multiple Values. It is a comma-separated list of types, enclosed in parentheses. In other words, a tuple groups multiple values into a single compound value.
break, continue, fallthrough, return, throw
The average unemployment is rising across job markets. But, when it is about software development and software programming, to requirement of iOS programmers are at higher side. iOS applicants with in-depth knowledge and skill-based training cum experience in iOS programming are able find their smooth ways to achieve their career goals. Besides, iOS has occupied the topmost place in the arena of programming software and application.
A iOS developer or programmer is expected a minimum salary of 40, 000 dollars per annum. Although the salary of an experienced iOS developer can reach to double the figure mentioned before. The salaries are very dependent upon the location, business, and the company’s requirements.
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