state

问题 I have seen several examples of a model extending ChangeNotifier using both 'extends' and 'with' keywords. I am not sure what the difference is. class myModel extends ChangeNotifier {...} class myModel with ChangeNotifier {...} What is the difference between those two? Which one should I use? 回答1: You can use either extends (to inherit) or with (as a mixin). Both ways give you access to the notifyListeners() method in ChangeNotifier . Inheritance Extending ChangeNotifier means that

问题 How can I save the state of multiple switches so when the application is quit and reopened, all of the switches are not at the same state they where before I quit it. Here is my very simple code for a quick homework manager I did. // // ViewController.swift // HomeworkManager // // Created by Nate Parker on 9/2/14. // Copyright (c) 2014 Nathan Parker. All rights reserved. // import UIKit class ViewController: UIViewController { override func viewDidLoad() { super.viewDidLoad() // Do any

问题 Based on an answer here I was inspired to try and make a program where the state monad could be swapped for the IO monad and it would still work. So far I came up with: {-# LANGUAGE FlexibleInstances #-} import Control.Monad.State class Monad m => Interaction m where getInput :: m String produceOutput :: String -> m () instance Interaction IO where getInput = getLine produceOutput = putStrLn instance Interaction (State String) where getInput = get produceOutput = put interactiveProgram ::

问题 Based on an answer here I was inspired to try and make a program where the state monad could be swapped for the IO monad and it would still work. So far I came up with: {-# LANGUAGE FlexibleInstances #-} import Control.Monad.State class Monad m => Interaction m where getInput :: m String produceOutput :: String -> m () instance Interaction IO where getInput = getLine produceOutput = putStrLn instance Interaction (State String) where getInput = get produceOutput = put interactiveProgram ::

问题 Based on an answer here I was inspired to try and make a program where the state monad could be swapped for the IO monad and it would still work. So far I came up with: {-# LANGUAGE FlexibleInstances #-} import Control.Monad.State class Monad m => Interaction m where getInput :: m String produceOutput :: String -> m () instance Interaction IO where getInput = getLine produceOutput = putStrLn instance Interaction (State String) where getInput = get produceOutput = put interactiveProgram ::

问题 In the following example: MapView displays elements of a ListView as annotations Clicking on a ListView element should result in painting it in blue color. Bonus if the MapView and ListView efficiently use the state object Modifying the DataSource of ListView seems to cause the conflict when the active attribute gets modified: You attempted to set the key 'active' with the value 'false' on an object that is meant to be immutable and has been frozen. What is the right way of setting the state?

问题 After a long struggle with the Page Lifecycle in ASP.NET and its performance, we've begun refactoring our web app to implement web services (plain-vanilla .asmx .NET web-services) and jQuery on the client-side. NOTE: this does not implement MVC or ASP.NET in any way, these are just web services. In both dispensations of the application, we generate all content dynamically in a single page. In the ASP.NET dispensation, this meant (due to the Page Lifecycle) that the entire page needed to be

问题 As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance. Closed 7 years ago . What kind of programming problems are state machines most suited for? I have read about parsers being implemented using state machines

问题 Given how flexible jinja templating can be with saltstack and the numerous pillar variables are merged into the template; I would find it useful to be able to get salt to 'render' the full sls out to screen before i push it out. Is there a way of doing this? 回答1: Just to answer my own question: I knew that state.show_top existed. So I tried state.show_sls, and voila! Exactly what I'm after. 来源： https://stackoverflow.com/questions/34191710/how-to-render-and-dump-the-file-sls-with-salt-stack

问题 I have written some state machine in C++ and Java but never in a functional language like Ocaml Problem is I don't know if I can just adapt code from the object languages versions, since in Ocaml records and variants are more powerful than class; So, I need an event-driven finite state machine (hierarchical like in UML), easily configurable Could someone experienced in the field post a simple sample of that ? Just to avoid the most common traps thanks :) EDIT 16/03 : Is it possible to do it