state | 易学教程

Where Should Model State Be Stored In Angular.js

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问题 I'm finding Angular's use of models confusing. Angular seems to take the approach that a model can be anything you like - I.E. Angular does not include an explicit model class and you can use vanilla JavaScript objects as models. In almost every Angular example I've seen, the model is effectively an object, either created by hand, or returned from an API call via a Resource. Because almost every Angular example I've looked at is simple, usually the model data stored on $scope in a controller

State Machine, Model Validations and RSpec

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问题 Here's my current class definition and spec: class Event < ActiveRecord::Base # ... state_machine :initial => :not_started do event :game_started do transition :not_started => :in_progress end event :game_ended do transition :in_progress => :final end event :game_postponed do transition [:not_started, :in_progress] => :postponed end state :not_started, :in_progress, :postponed do validate :end_time_before_final end end def end_time_before_final return if end_time.blank? errors.add :end_time,

Save and restore expanded/collapsed state of an ExpandableListActivity

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I have an ExpandableListActivity (using a SimpleCursorTreeAdapter) which starts another activity when the user clicks on a child-element. When pressing the back-button in the new activity all the list-items are collapsed again. How do I save the expanded state of the ExpandableListActivity and restore it again. I already tried to implemented onSaveInstanceState() and onRestoreInstanceState() like this... @Override protected void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); Parcelable listState = getExpandableListView().onSaveInstanceState(); outState

ReactJS this.state null

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Let me preface this by saying I am a novice to ReactJS. I am trying to learn by making a simple site that populates data using React. I have a JSON file that contains link data that will be looped through with map. I have tried setting it as the components state then passing it to the navbar links via a prop but I am getting "Uncaught TypeError: Cannot read property 'data' of null" I tried to look around for solutions but could not find anything. Note: When I try to hard code an object and map through it that way it returns map is undefined. However I am not sure that is directly related to

When do I choose React state Vs Redux Store

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I've been learning Redux and a part I'm unclear of is, how do I make a determination between using react state vs redux store and then dispatching actions. from my reading so far it looks like I could use React state in place of Redux store and still get things done. I understand the separation of concerns with using Redux store and just having 1 container component and the rest of it as stateless component but how do I make the determination of when to use React state Vs redux store is not very clear to me. Can someone please help? Thanks! If the state doesn't need to be shared with other

How to restore a minimized Window in code-behind?

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This is somewhat of a mundane question but it seems to me there is no in-built method for it in WPF. There only seems to be the WindowState property which being an enum does not help since i cannot tell whether the Window was in the Normal or Maximized state before being minimized. When clicking the taskbar icon the window is being restored just as expected, assuming its prior state, but i cannot seem to find any defined method which does that. So i have been wondering if i am just missing something or if i need to use some custom interaction logic. ( I'll post my current solution as answer )

comparison of ways to maintain state

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There are various ways to maintain user state using in web development. These are the ones that I can think of right now: Query String Cookies Form Methods (Get and Post) Viewstate (ASP.NET only I guess) Session (InProc Web server) Session (Dedicated web server) Session (Database) Local Persistence (Google Gears) (thanks Steve Moyer) etc. I know that each method has its own advantages and disadvantages like cookies not being secure and QueryString having a length limit and being plain ugly to look at! ;) But, when designing a web application I am always confused as to what methods to use for

Can a `ST`-like monad be executed purely (without the `ST` library)?

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This post is literate Haskell. Just put in a file like "pad.lhs" and ghci will be able to run it. > {-# LANGUAGE GADTs, Rank2Types #-} > import Control.Monad > import Control.Monad.ST > import Data.STRef Okay, so I was able to figure how to represent the ST monad in pure code. First we start with our reference type. Its specific value is not really important. The most important thing is that PT s a should not be isomorphic to any other type forall s . (In particular, it should be isomorphic to neither () nor Void .) > newtype PTRef s a = Ref {unref :: s a} -- This is defined liked this to make

Saving Fragment State on Orientation Change

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问题 I'm creating a file manager app for Android, and two classes below are the majority of the logic that goes into doing that. What I'm doing is that on startup of the ContentList, it adds the ContentListFragment to the container layout in the ContestList xml. By adding the ContentListFragment, I get the current path, then call setFileDir(String S) that basically gets the File at the passed in path, getting the list of Files at that location, initializing the array, and then initializing the

STArray documentation for newbies and State/ST related questions

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I have a hard time to understand STArray from the documentation and other howtos/discussion I've found through Google. I've got some more related questions below. According to the documentation, STArray s are Mutable boxed and unboxed arrays in the ST monad. This gave me the impression, that STArray is meant to be used as a state being passed around between functions (imagine you have a vector that has to be updated often). Apparently this is used differently though: ST s (STArray s a e) What is the state s here? If it is used internally, then why is this not hidden from the user? This also