swift2

问题 I have a generic class: class PaginatedTableViewController <GenericElement, Source: PaginationDataSource where Source.PaginatedGenericElement == GenericElement>: UITableViewController and another that I try to instantiate from storyboard: class CandidatesTableViewController: PaginatedTableViewController<Match, MatchPaginationDataSource> I can't find CandidatesTableViewController in the storyboard Custom Class dropdown menu. If I force it then cast my controller in code, app crashes at runtime

问题 My app use google+ signin and in my appdelegate.swift i have: func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { // Override point for customization after application launch. var configureError: NSError? GGLContext.sharedInstance().configureWithError(&configureError) assert(configureError == nil, "Error configuring Google services: \(configureError)") GIDSignIn.sharedInstance().delegate = self return true } func

问题 After updating to Xcode 7 and then the iOS 9 beta 5 on my iPhone, none of my UITableViews are displaying data, except one. They are all downloading information from my Parse database, and the one that works, is downloading everything perfectly for one section of the table, but not the other. The other 3 table views download the information, and calculate the correct number of rows, however nothing is being displayed. I tried just displaying static text for all cells, however it is not even

问题 This question already has answers here : Error: Immutable value passed on reduce function (3 answers) Closed 4 years ago . I'm using Xcode 6.4 I have an array of UIViews and I want to convert to a Dictionary with keys "v0", "v1"... . Like so: var dict = [String:UIView]() for (index, view) in enumerate(views) { dict["v\(index)"] = view } dict //=> ["v0": <view0>, "v1": <view1> ...] This works, but I'm trying to do this in a more functional style. I guess it bothers me that I have to create the

问题 In Swift 2.0, Apple introduced a new way to handle errors (do-try-catch). And few days ago in Beta 6 an even newer keyword was introduced ( try? ). Also, knew that I can use try! . What's the difference between the 3 keywords, and when to use each? 回答1: Updated for Swift 5.1 Assume the following throwing function: enum ThrowableError: Error { case badError(howBad: Int) } func doSomething(everythingIsFine: Bool = false) throws -> String { if everythingIsFine { return "Everything is ok" } else

问题 Recently I've saw the WWDC 2015 keynote from Apple. I also looked at some documentation but I can't find a "pattern matching in if" section, how it was written on one of the slides which they have shown. (68min 00sec video from Apple Events) Do you know what's this refers to? Or the syntax? 回答1: All it really means is that if statements now support pattern matching like switch statements already have. For example, the following is now a valid way of using if/else if/else statements to "switch

问题 I'm writing an iOS application using Swift 2 and I would like to save profile picture of an account locally in a Realm database. I can't find any documentation or people talking about that. Is it possible? And how? May be is it bad to do that? 回答1: You can store images as NSData . Given you have the URL of an image, which you want to store locally, here is a code snippet how that can be achieved. class MyImageBlob { var data: NSData? } // Working Example let url = NSURL(string: "http://images

问题 For Sept 2015, here's exactly how you make a singleton in Swift: public class Model { static let shared = Model() // ( for ocd friends ... private init() {} ) func test()->Double { return 3.33 } } then elsewhere... // file ViewController.swift, say import UIKit class ViewController:UIViewController { override func viewDidLoad() { super.viewDidLoad() print("view controller loaded!") print("singleton test! \( Model.shared.test() )") } } No problem. However. I add this little thing... public let

问题 I have this code from here to do synchronous request of a URL on Swift 2. func send(url: String, f: (String)-> ()) { var request = NSURLRequest(URL: NSURL(string: url)!) var response: NSURLResponse? var error: NSErrorPointer = nil var data = NSURLConnection.sendSynchronousRequest(request, returningResponse: &response, error: error) var reply = NSString(data: data, encoding: NSUTF8StringEncoding) f(reply) } but the function NSURLConnection.sendSynchronousRequest(request, returningResponse:

问题 I'm new to Swift and I'm trying to learn how to use Core Data. But I'm getting this error and I'm not sure what I've done wrong. I've searched online and tried a few things but I can't get it right. Failed to call designated initializer on NSManagedObject class 'FirstCoreData.Course' When this line executes: ncvc.currentCourse = newCourse In this function: class TableViewController: UITableViewController, AddCourseViewControllerDelegate { var managedObjectContext = NSManagedObjectContext.init