swift2

问题 I'm currently working on introspection in Swift 2 and have Problems getting the specific type for an Array (in this example an Array<String> ). var prop = obj.valueForKey("strings")! if prop is Array<String> { println("true") } if prop is Array<Int> { println("true") } Output is: true true while it should be true false Is there a way to find out the type for the members of the Array? For example, if I daclared the Array as Array<String> I want to get String or at least be able to check if it

问题 This question is in reference to this one: Object positioning is off so I implemented the code again: let xAxisSpawnLocations: [CGFloat] = { var spawnLocations:[CGFloat] = [] //Create 5 possible spawn locations let numberOfNodes = 5 for i in 0...numberOfNodes - 1 { /* Spacing between nodes will change if: 1) number of nodes is changed, 2) screen width is changed, 3) node's size is changed. */ var xPosition = (frame.maxX - player.size.width) / CGFloat((numberOfNodes - 1)) * CGFloat(i) //add a

问题 I have tried this with CGFloat and i am getting the following error: Can not invoke stride with an argument list of type '(CGFloat by: CGFloat)' for var min:CGFloat = 0.0; min<=45.0; min = min+value { print("\(min)") } to: for min:CGFloat in 0.stride(CGFloat(55.0), by: min+value) { print("\(min)") } 回答1: Below is the latest overload for stride. You can use cast the number to CGFloat for the stride. for min in (0 as CGFloat).stride(to: 55, by: value) { print("\(min)") } However, stride returns

问题 I have a Login project. The first view controller is NavController and I need to pass user data to tabBarController where I have 3 NavigationControllers. I tried this. let openNewVC = self.storyboard?.instantiateViewControllerWithIdentifier("mainNavID") as! UITabBarController //openNewVC.token = token! self.navigationController?.pushViewController(openNewVC, animated: true) 回答1: You can pass the data from your first view Controller to view controllers which are embedded like as below in

问题 I have function curry that takes a function (A, B) -> C as an argument, and returns A -> B -> C . It works fine on function g(a: Int, b: Int) -> Int . Also, I have function f , that is polymorphic, so its type is ambigous. Here is the code: func g(a: Int, b: Int) -> Int { return a + b } func f(a: Int, b: Int) -> Int { return a + b } func f(a: Float, b: Float) -> Float { return a + b } func curry<A, B, C>(f: (A, B) -> C) -> A -> B -> C { return { a in { b in f(a, b) } } } let curriedG = curry

问题 I have a table view where i want the view controller to pop instead of segue when the cell is selected although I am getting this error "Value of type 'UINavigationController' has no member 'popViewController'"-- Any ideas??? Please note: I am using swift 2 and xcode7 回答1: I think in swift 2 and Xcode 7 the function is: navigationController?.popViewControllerAnimated(true) 来源： https://stackoverflow.com/questions/40319160/value-type-error-swift-xcode

问题 I want to add images in array in sequence after downloading. I am appending images in array after downloading one by one but they are not in sequence. Can any one please tell me what is best way to do this. var queue: NSOperationQueue = { let _queue = NSOperationQueue() _queue.maxConcurrentOperationCount = 4 return _queue }() var imageArrayNsData : [NSData] = [] let session = NSURLSession.sharedSession() @IBAction func didClickOnStart(sender: AnyObject) { queue.cancelAllOperations() let

问题 Whenever I download an image from Firebase Storage it download's perfectly, but once I try to change the imageview "my" to it, the imageview disappears. I don't have constraints and I navigated to the local URL and found the image perfectly there. Any help? Am I doing something wrong? func loadImages(){ let documentDirectoryURL = try! NSFileManager.defaultManager().URLForDirectory(.DocumentDirectory, inDomain: .UserDomainMask, appropriateForURL: nil, create: true) let newRef = storageRef!

问题 I have an array that contains numbers and empty strings, like ["", "2", "4", "", "", "1", "2", ""] . I would like to pare this down to a list of numbers, like [2,4,1,2] . My first effort split this into two steps, first strip out the empty strings, then do the string-to-integer conversion. However, my code for step one isn't working as desired. for (index,value) in tempArray.enumerate(){ if value == "" { tempArray.removeAtIndex(index) } } This fails, I believe because it is using the index

问题 I have an array that contains numbers and empty strings, like ["", "2", "4", "", "", "1", "2", ""] . I would like to pare this down to a list of numbers, like [2,4,1,2] . My first effort split this into two steps, first strip out the empty strings, then do the string-to-integer conversion. However, my code for step one isn't working as desired. for (index,value) in tempArray.enumerate(){ if value == "" { tempArray.removeAtIndex(index) } } This fails, I believe because it is using the index