protocols

问题 My task is to create a WPF application that when users click callto: and tel: links in the browser (Chome, IE) the default application that opens them is the Windows 10 WPF application that I have created and to handle them. I have tried changing the registry by writing a script and by manually entering the path to my published .exe that Visual Studio has output but neither of these has worked, whenever I click a callto: or tel: link the default program that is opened is still a voip

问题 I would say this problem is about proper declaration of extension. I would like to extend Array filled with generic Elements, where Element conforms to Equatable. I've managed to do that by : extension Array where Element: Equatable{ // my code } However I'd like to know how to properly declare extension when the Array filled with Equatable elements is inside an Optional? I know that in this case I am actually extending protocol Optional, but I can't figure out the rest I was thinking

问题 I would say this problem is about proper declaration of extension. I would like to extend Array filled with generic Elements, where Element conforms to Equatable. I've managed to do that by : extension Array where Element: Equatable{ // my code } However I'd like to know how to properly declare extension when the Array filled with Equatable elements is inside an Optional? I know that in this case I am actually extending protocol Optional, but I can't figure out the rest I was thinking

问题 I don't think this can be done but I'll ask anyway. I have a protocol: protocol X {} And a class: class Y:X {} In the rest of my code I refer to everything using the protocol X. In that code I would like to be able to do something like: let a:X = ... let b:X = ... if a == b {...} The problem is that if I try to implement Equatable : protocol X: Equatable {} func ==(lhs:X, hrs:X) -> Bool { if let l = lhs as? Y, let r = hrs as? Y { return l.something == r.something } return false } The idea to

问题 I have two protocols: Pen and InstrumentForProfessional . I'd like to make any Pen to be an InstrumentForProfessional : protocol Pen { var title: String {get} var color: UIColor {get} } protocol Watch {} // Also Instrument for professional protocol Tiger {} // Not an instrument protocol InstrumentForProfessional { var title: String {get} } class ApplePen: Pen { var title: String = "CodePen" var color: UIColor = .blue } extension Pen: InstrumentForProfessional {} // Unable to make ApplePen an

问题 I want to know which protocol is used to send push notification to android devices and which to send push notification requests to GCM. Whether it is HTTP, HTTPS or some thing else? 回答1: The protocols of the communication between the 3rd party server and GCM server (HTTP or XMPP) were already mentioned in the other answers. The protocol of the communication between the device and GCM server is not discussed in the GCM documentation, since you never have to access it directly as an Android

问题 I want to know which protocol is used to send push notification to android devices and which to send push notification requests to GCM. Whether it is HTTP, HTTPS or some thing else? 回答1: The protocols of the communication between the 3rd party server and GCM server (HTTP or XMPP) were already mentioned in the other answers. The protocol of the communication between the device and GCM server is not discussed in the GCM documentation, since you never have to access it directly as an Android

问题 I've got the following snippet: protocol MyProtocol: Identifiable where ID == UUID { var id: UUID { get } } var test: [MyProtocol] = [] Protocol 'MyProtocol' can only be used as a generic constraint because it has Self or associated type requirements Why doesn't this work? Shouldn't the where ID == UUID remove the ambiguity the error is concerned with? Am I missing something here? I think this question is similar to this one: Usage of protocols as array types and function parameters in swift

问题 I have this code: from tkinter import * w = Tk() w.protocol('WM_TAKE_FOCUS', print('hello world')) mainloop() It prints hello world only once, and then it stops working. No more hello world Basically WM_TAKE_FOCUS does not work. 回答1: You can bind a function to the <FocusIn> event. When you bind to the root window the binding is applied to every widget in the root window, so if you only want to do something when the window as a whole gets focus you'll need to compare event.widget to the root

问题 I have this code: from tkinter import * w = Tk() w.protocol('WM_TAKE_FOCUS', print('hello world')) mainloop() It prints hello world only once, and then it stops working. No more hello world Basically WM_TAKE_FOCUS does not work. 回答1: You can bind a function to the <FocusIn> event. When you bind to the root window the binding is applied to every widget in the root window, so if you only want to do something when the window as a whole gets focus you'll need to compare event.widget to the root