delegate

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I have a method that has a custom segue in my viewController that looks like this: func gameOver() { performSegueWithIdentifier("GameOver", sender: nil) } I call the method like so in GameScene.swift: GameViewController().gameOver() I double checked the segue name and it is correct. Whenever I call this in my GameScene.swift file I get the SIGABRT message and I don't know why. I tried calling the function with only a println() message and it worked. Any advice on why this is occurring and how I can successfully call the method in the

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I have seen a few mentions of this idiom (including on SO ): // Deliberately empty subscriber public event EventHandler AskQuestion = delegate {}; The upside is clear - it avoids the need to check for null before raising the event. However, I am keen to understand if there are any downsides. For example, is it something that is in widespread use and is transparent enough that it won't cause a maintenance headache? Is there any appreciable performance hit of the empty event subscriber call? 回答1: The only downside is a very slight performance

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: How do you know what is the current page/view displayed inside an UIPageViewController ? I have overridden the viewDidAppear method of my child views, so that they send an id to the parent view in their viewDidAppear method. However, the problem is this: i cannot reliably use that id as id for the displayed page. because if the user turns the page but halfway through decides to stop the turning and put the page back, viewDidAppear will already have been called. (the view is visible behind the curled page). Maybe i should only switch to a new

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Do I need to subscribe/unsubscribe to individual elements of an array? I want to update each table view cell individually to reflect changes in the backing array. By changes I mean not append/remove operations but update of the properties of the objects of the array. I hope I was able to explain what I want to achieve. Thanks 回答1: To use KVO, declare the model object with dynamic properties: class Foo: NSObject { @objc dynamic var bar: String // in Swift 3, `@objc` is not necessary; in Swift 4 we must make this explicit init(bar: String) {

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: We have a supplier who provides a library for access to their hardware. Unfortunately, if you have multiple devices, you need to import their library multiple times, with different dll names. As a consequence, we have a metric ton of duplicated code, and I'm worried that it will soon become be a maintenance nightmare. What we have at the moment is somthing like: namespace MyNamespace { public static class Device01 { public const string DLL_NAME = @"Device01.dll"; [DllImport(DLL_NAME, EntryPoint = "_function1")] public static extern int

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I've always used completion handlers. With NSURLConnection and now with NSURLSession . It's led to my code being really untidy, especially I have request within request within request. I wanted to try using delegates in NSURLSession to implement something I've done untidily with NSURLConnection . So I created a NSURLSession , and created a dataTask : NSURLSessionDataTask *dataTask = [overallSession dataTaskWithURL:url completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { if(error == nil) { NSString * text = [[NSString

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 由 翻译 强力驱动 问题: I need a UITableView delegate method that need to be called from another function at compilation time...is there any default UITableView delegate methods that i can use? if not, please comment on how to add an extra delegate method in addition to the existing ones. Thanks in advance 回答1: Make sure you set UITableview Delegate in either way - from NIB or programatially Using NIB From Nib :- Programatically :- then:- -( void ) viewWillAppear :( BOOL ) animated { tblService . delegate = self ; tblService . dataSource = self ; [ super

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I need a method that takes a MethodInfo instance representing a non-generic static method with arbitrary signature and returns a delegate bound to that method that could later be invoked using Delegate.DynamicInvoke using System; using System.Reflection; class Program { static void Main() { var method = CreateDelegate(typeof (Console).GetMethod("WriteLine", new[] {typeof (string)})); method.DynamicInvoke("Hello world"); } static Delegate CreateDelegate(MethodInfo method) { if (method == null) { throw new ArgumentNullException("method"); } if

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 由 翻译 强力驱动 问题: I've been looking into modifying the AngularJS ng-click directive to add some additional features. I have a few different ideas of what to use it for, but a simple one is to add Google Analytics tracking to all ng-clicks, another is to prevent double clicking. To do this my first thought was to use a decorator. So something like this: app . config ([ '$provide' , function ( $provide ) { $provide . decorator ( 'ngClickDirective' , [ '$delegate' , function ( $delegate ) { // Trigger Google Analytics tracking here return $delegate ; }

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Today I was thinking about declaring this: private delegate double ChangeListAction(string param1, int number); but why not use this: private Func ChangeListAction; or if ChangeListAction would have no return value I could use: private Action ChangeListAction; so where is the advantage in declaring a delegate with the delegate keyword? Is it because of .NET 1.1, and with .NET 2.0 came Action and with .NET 3.5 came Func ? 回答1: The advantage is clarity. By giving the type an explicit name it is more clear to the reader what it does. It will