tclementdev

libdispatch efficiency tips

The libdispatch is one of the most misused API due to the way it was presented to us when it was introduced and for many years after that, and due to the confusing documentation and API. This page is a compilation of important things to know if you're going to use this library. Many references are available at the end of this document pointing to comments from Apple's very own libdispatch maintainer (Pierre Habouzit).

My take-aways are:

• You should create very few, long-lived, well-defined queues. These queues should be seen as execution contexts in your program (gui, background work, ...) that benefit from executing in parallel. An important thing to note is that if these queues are all active at once, you will get as many threads running. In most apps, you probably do not need to create more than 3 or 4 queues.

• Go serial first, and as you find performance bottle necks, measure why, and if concurrency helps, apply with care, always validating under system pressure. Reuse

smileyborg

// UICollectionView Objective-C example

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
        
    NSIndexPath *selectedIndexPath = [[self.collectionView indexPathsForSelectedItems] firstObject];
    if (selectedIndexPath != nil) {
        id<UIViewControllerTransitionCoordinator> coordinator = self.transitionCoordinator;
        if (coordinator != nil) {
            [coordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context) {

alexathylane

From episode "5 - Setting Up Universal Links (Deep Linking)" on the Inside iOS Dev Podcast

1) Create an apple-app-site-association file that contains JSON data about the URLs that your app can handle.

• Create apple-app-site-association text file without .json file extension
• Use application/json MIME type for the text file
• Have the following contents of the file similar to this format:

   {
   	"applinks": {

"apps": [],

evgeniyd

/// The Medium artcile, discussing the approach
/// https://medium.com/@euginedubinin/swift-useful-autoclosure-when-presenting-uialertviewcontroller-b592d1643a50#.kx0fuqm1x

final class NoteViewController: UIViewController {
  
  // ... set up target-action for an Edit UIButton somewhere here ...
  
  private dynamic func handleEditButton() {
    presentEditConfirmationDialog(onEdit: self.editArticle(), 
                                  onCancel: () )  /* assuming you have nothing to do upon cancellation */

jbehrens94

import Foundation

// First define the algorithm protocol.
protocol LoadBehaviour {
    func execute() -> String
}

// Define the algorithms.
// Algorithm 1
class CoreDataManager: LoadBehaviour {

leemorgan

///Returns the input value clamped to the lower and upper limits.
func clamp<T: Comparable>(value: T, lower: T, upper: T) -> T {
	return min(max(value, lower), upper)
}


//-----------------------------------------------
// Example usage

let proposedIndex = 6

leecade

brew working with Xcode-beta 7

$ xcode-select --install
$ sudo xcode-select -s /Applications/Xcode-beta.app/Contents/Developer
$ xcode-select -p

ref: https://github.com/Homebrew/homebrew/labels/10.11

makmanalp

Note: these are pretty rough notes I made for my team on the fly as I was reading through some pages. Some could be mildly inaccurate but hopefully not terribly so. I might resort to convenient fiction & simplification sometimes.

My top contenders, mostly based on popularity / community etc:

• Angular
• Backbone
• React
• Ember

Mostly about MVC (or derivatives, MVP / MVVM).

arturlector

Вопросы на собеседование iOS разработчика (дополненное издание):

General:

• Что такое полиморфизм?

• Что такое *инкапсуляция? Что такое *нарушение инкапсуляции?

• Чем абстрактный класс отличается от интерфейса?

• Расскажите о паттерне MVC. Чем отличается пассивная модель от активной?

irskep

func getUIImageForRGBAData(#width: UInt, #height: UInt, #data: NSData) -> UIImage? {
  let pixelData = data.bytes
  let bytesPerPixel:UInt = 4
  let scanWidth = bytesPerPixel * width

  let provider = CGDataProviderCreateWithData(nil, pixelData, height * scanWidth, nil)

  let colorSpaceRef = CGColorSpaceCreateDeviceRGB()
  var bitmapInfo:CGBitmapInfo = .ByteOrderDefault;
  bitmapInfo |= CGBitmapInfo(CGImageAlphaInfo.Last.rawValue)