swift4.1

Why does compactMap return a nil result?

由 我与影子孤独终老i 提交于 2021-02-08 12:33:09
问题 Consider this code snippet: var a: String? = "abc" var b: String? let result = [a, b].compactMap { $0 } After executing it, result will be ["abc"] which is the expected result. The element of result ( ElementOfResult ) here is String . print(type(of: result)) Array<String> Now to the interesting part. After changing the snippet to var a: String? = "abc" var b: Int? let result = [a, b].compactMap { $0 } and executing it, result will be [Optional("abc"), nil] The element of result (

Swift 4.1 deinitialize and deallocate(capacity:) deprecated

由 亡梦爱人 提交于 2021-02-07 14:24:03
问题 I've been saying this to form a C array of CGPoint: let arr = UnsafeMutablePointer<CGPoint>.allocate(capacity:4) defer { arr.deinitialize() arr.deallocate(capacity:4) } arr[0] = CGPoint(x:0,y:0) arr[1] = CGPoint(x:50,y:50) arr[2] = CGPoint(x:50,y:50) arr[3] = CGPoint(x:0,y:100) Now (Swift 4.1 in the Xcode 9.3 beta) both deinitialize and deallocate(capacity:) are deprecated. It looks like what I'm supposed to say now might be: defer { arr.deinitialize(count:4) arr.deallocate() } Is that right?

Xcode 9.2 is not showing Swift 4.1

由 混江龙づ霸主 提交于 2019-12-23 16:08:51
问题 Apple compatibility documentation is mentioning that: Swift 4.1, the default version of Swift that’s included in Xcode 9.2. Yet, using Xcode Version 9.2 (9C40b), the choice of Swift Language Version that I have are 3.2 and 4.0: Is it a mistake in the documentation or a problem in Xcode? Can I use Swift 4.1 with Xcode 9.2? Will I be able to submit to AppStore using it? 回答1: Apple documentation was incorrect, Swift documentation is correct. Well, to be double sure of which version is supported,

Can not conform to protocol by creating extension with Where Clauses

由 本小妞迷上赌 提交于 2019-12-22 06:42:11
问题 protocol Typographable { func setTypography(_ typography: Typography) } extension UILabel: Typographable {} extension Typographable where Self == UILabel { func setTypography(_ typography: Typography) { self.font = typography.font self.textColor = typography.textColor self.textAlignment = typography.textAlignment self.numberOfLines = typography.numberOfLines } } I have create a protocol Typographable , the UILabel implement this protocol, and the implementation is in the extension

Decodable and JSON, 2 datatypes for same variable

由 纵饮孤独 提交于 2019-12-21 06:04:46
问题 I'm using the Decodable protocol to decode some json, but I've run into a problem: I'm getting an answer back, where a longitude and a latitide can be either an interger (latitude = 0) if there's no geo location data added to the element, and a String (fx. latitude = "25.047880") if there's geodata available. Now when I decode the json, I don't know how to build my Struct, as the long and lat can't both be String and Int.. So I'm getting a decode error when fetching elements where both cases

Status bar could not find cached time string image. Rendering in-process

由 天大地大妈咪最大 提交于 2019-12-20 08:21:05
问题 I get the above runtime message after I upgraded to Swift4.1 and Xcode 9.3. Before the upgrade I did not have this message in my console window. Status bar could not find cached time string image. Rendering in-process. comes up every few minutes as long as I have the App running. It sees to me there is no negative side effect, my App is running, as usual, I have not seen any problems. I use the standard Status Bar, have not changed to modify it in any way. Question 1: Would there be a problem

Type 'NSAttributedStringKey' (aka 'NSString') has no member 'foregroundColor'

由 ∥☆過路亽．° 提交于 2019-12-13 04:43:36
问题 Below is line of code for the above mentioned issue. This issue is occurred in Swift 4.1 . let textAttributes = [NSAttributedStringKey.foregroundColor:UIColor.white] navigationController?.navigationBar.titleTextAttributes = textAttributes 回答1: I've fixed this problem by replacing the Key for Attributed String. Here is my updated Code is: let textAttributes = [NSForegroundColorAttributeName : UIColor.white] navigationController?.navigationBar.titleTextAttributes = textAttributes 来源： https:/

Swift 4.1 Codable/Decodable Nested Array

由 混江龙づ霸主 提交于 2019-12-08 23:35:34
Need some help with more complicated json, with the newest swift4.1 encoder/decoder: struct: struct LMSRequest: Decodable { let id : Int? let method : String? let params : [String]? enum CodingKeys: String, CodingKey { case id = "id" case method = "method" case params = "params" } init(from decoder: Decoder) throws { let values = try decoder.container(keyedBy: CodingKeys.self) id = try values.decodeIfPresent(Int.self, forKey: .id) method = try values.decodeIfPresent(String.self, forKey: .method) params = try values.decodeIfPresent([String].self, forKey: .params) }} json: let json = """ { "id":

Swift 4.1 Codable/Decodable Nested Array

由 落花浮王杯 提交于 2019-12-08 05:38:05
问题 Need some help with more complicated json, with the newest swift4.1 encoder/decoder: struct: struct LMSRequest: Decodable { let id : Int? let method : String? let params : [String]? enum CodingKeys: String, CodingKey { case id = "id" case method = "method" case params = "params" } init(from decoder: Decoder) throws { let values = try decoder.container(keyedBy: CodingKeys.self) id = try values.decodeIfPresent(Int.self, forKey: .id) method = try values.decodeIfPresent(String.self, forKey:

Can not conform to protocol by creating extension with Where Clauses

由 本小妞迷上赌 提交于 2019-12-05 08:57:13
protocol Typographable { func setTypography(_ typography: Typography) } extension UILabel: Typographable {} extension Typographable where Self == UILabel { func setTypography(_ typography: Typography) { self.font = typography.font self.textColor = typography.textColor self.textAlignment = typography.textAlignment self.numberOfLines = typography.numberOfLines } } I have create a protocol Typographable , the UILabel implement this protocol, and the implementation is in the extension Typographable where Self == UILabel . it works perfectly in swift 4.0, but it not works any more in swift 4.1, the
订阅 swift4.1