nserror

问题 Let's say that you have a function like this: func getSomething(error: NSErrorPointer) -> Something and you typically use it this way: var error : NSError? = nil let a = getSomething(&error) What is an idiomatic way to check for error here? More specific questions: If error == nil can we assume that a will never be nil and vice versa? What should we check first: error (for its nilness) or a (to confirm that it's not a nil)? Can a != nil && error != nil be true in some cases? Thank you! 回答1:

问题 my app is supposed to make a request from a server every 10 seconds or so with a specific url, change some attributes in the url, and then show the request in another view called "updateView" or if any network error occurred display the error. The first part works fine but if i switch of wifi for example the app crashes. How do i fix this and how do i display the various errors? Thanks in advance!! Here's my code (this is the method which gets called every 10 seconds): - (void)serverUpdate{

问题 I've got a rather large body of Swift 3 code for Mac OS 10.11 and up (using Xcode 8.2.1). There are a number of processes, among them a GUI application and a background service. Both of these use a custom URLProtocol , which is implemented in a framework (imported by both application and service). The protocol sometimes may generate instances of an enum that conforms to Error , which it catches and handles appropriately (generally by using the URLProtocolClient to toss them up to the

问题 For this request: Alamofire.request("https://google.com").responseCollection { (response: DataResponse<[User]>) in guard response.result.isSuccess else { print(response.error) return } } I see this printed in the console: Optional(my_app_name.BackendError.jsonSerialization(Alamofire.AFError.responseSerializationFailed(Alamofire.AFError.ResponseSerializationFailureReason.jsonSerializationFailed(Error Domain=NSCocoaErrorDomain Code=3840 "Invalid value around character 0." UserInfo=

问题 I am getting the following error when running my code from the xcode. Error Domain=NSURLErrorDomain Code=-1012 "The operation couldn’t be completed. (NSURLErrorDomain error -1012.)" UserInfo=0x17166b740 {NSErrorFailingURLStringKey= https://..../move/resource/v1/user/me/activity/summary?start_date=2015-01-21&end_date=2015-01-14&detail=true , NSUnderlyingError=0x17405b630 "The operation couldn’t be completed. (kCFErrorDomainCFNetwork error -1012.)", NSErrorFailingURLKey= https://..../move

问题 My Swift app has a custom error system where MyError is just a simple class conforming to Error . Now the app seems to crash whenever a third-party library (PromiseKit) tries to convert this error to NSError and then to access its domain property. In my own code, doing this works as expected, so why does it crash in the library and what's the proper way of dealing with it? Crashed: com.apple.main-thread 0 libswiftCore.dylib 0x1011d86d8 _hidden#19226_ (__hidden#19178_:1788) 1 libswiftCore

问题 iOS 9.2.1, Xcode 7.2.1, ARC enabled I am using the following method to check for failures of SKProductsRequest and SKReceiptRefreshRequest : - (void)request:(SKRequest *)request didFailWithError:(NSError *)error { NSLog(@"error: %@", error); } My question is specifically about SKReceiptRefreshRequest . I am testing for two conditions, (1) when the user cancels the sign-in to iTunes Store for the receipt request and (2) when the user tries to sign-in and there is no connection (Air Plane Mode)

问题 I am creating a library that should return errors so I'm wondering which one should use for my purposes. UPDATE: I should clarify, the returned result will be from a asynchronous call so I need to inform to the user if there was an error and I would like to know which type I should use Error or NSError. 回答1: NSError is a Cocoa class An NSError object encapsulates information about an error condition in an extendable, object-oriented manner. It consists of a predefined error domain, a domain

问题 So this code runs fine on the iOS Simulators, but not on my iPad Mini var sound = NSURL(fileURLWithPath:"/Users/Dan/Documents/XCode Code/Colors- Tabbed?/Colors- Tabbed?/Sweg.aiff") var audioPlayer = AVAudioPlayer() audioPlayer = AVAudioPlayer(contentsOfURL: sound, error: &error) var error: NSError? I get the error "unexpectedly found nil while unwrapping an Optional value" on the last line. 回答1: It looks like AVAudioPlayer hasn't been audited yet. It returns an implicitly unwrapped optional,

问题 I'm using a lot of async network request (btw any network request in iOS need to by async) and I'm finding way to better handle errors from Apple's dataTaskWithRequest which not supports throws . I have code like that: func sendRequest(someData: MyCustomClass?, completion: (response: NSData?) -> ()) { let request = NSURLRequest(URL: NSURL(string: "http://google.com")!) if someData == nil { // throw my custom error } let task = NSURLSession.sharedSession().dataTaskWithRequest(request) { data,