UniRx官方入门文档

UniRx 官方文档翻译

UniRx官方入门文档
UniRx入门系列一
UniRx入门系列二
UniRx入门系列三
UniRx入门系列四
UniRx入门系列五

UniRx 基于Unity的响应式编程框架

什么是UniRx?

UniRx(Unity的响应式编程框架)是.Net响应式编程框架的重新实现版本。官方的Rx的实现方式是非常棒的。但是，在Unity中使用会有一些问题；在IOS的IL2CPP中有兼容性的问题。UniRx修复这些问题，并针对Unity添加了一些特别的工具。支持的平台包括PC/Mac/Android/iOS/WebGL/WindowsStore/等等。

UniRx可在Asset Store（免费）中下载： http://u3d.as/content/neuecc/uni-rx-reactive-extensions-for-unity/7tT

博客信息更新：https://medium.com/@neuecc

Unity Forums 在线支持，有问题随时向我提问：http://forum.unity3d.com/threads/248535-UniRx-Reactive-Extensions-for-Unity

发现说明： UniRx/releases

UniRx 作为核心库+平台适配器（MainThreadScheduler/FromCoroutinue/etf)+框架（ObservableTriggers/ReactiveProperty/etc）

注意：async/await 集成（UniRx.Async）被分离到Cysharp/UniTask 7.0之后的版本

为什么使用Rx?

通常，在Unity对网络操作要求使用WWW和Coroutine.但是出于以下几点原因（或者其它原因）使用协程来进行异步操作并不顺手：

1.虽然协程的返回类型必须是IEnumerator,但是协程不能返回任何值。
2.因为yield return 语句不能被try-catch结构体包裹，协程中不能处理异常。

这种缺乏可组合性导致程序的紧耦合，往往造成IEnumators中逻辑过于复杂。

Rx可以解决异步调用的“伤痛”,Rx 是一个使用可观察集合和LINQ风格查询运算符组合成的基于异步和基于事件的可编程库。

游戏循环（every Update,OnCollisionEnter),传感器数据（Kinect,Leap Motion,VR Input 等等）这些类型的事件。Rx将事件表示为响应式序列。通过使用LINQ查询运算符，Rx变得容易组合且支持基于时间的操作。

Unity通常是单线程的，但是UniRx促进了多线程joins、cancel 访问GameObject，等等。

UniRx为UGUI提供了UI编程。所有的UI事件（clicked,valuechanged,等）均可以被转化为UniRx的事件流。

Unity 在2017之后支持C# 中的astnc/await。UniRx 为Unity提供了更轻量、强大的async/await集成。请看： Cysharp/UniTask.

介绍

非常棒的介绍Rx的文章：The introduction to Reactive Programming you’ve been missing.

以下代码使用UniRx实现了文章中的双击检测事例：

var clickStream=Observable.EveryUpdate()
.Where(_=>Input.GetMouseButtonDown(0));clickStream.Buffer(clickStream.Throttle(TimeSpan.FromMilliseconds(250))).Where(xs => xs.Count >= 2).Subscribe(xs => Debug.Log("DoubleClick Detected! Count:" + xs.Count));

本事例演示了以下功能（仅仅使用5行代码）：

游戏循环（Update）作为事件流
可组合事件流
合并自身流
易于处理基于时间的操作

网络操作

使用ObservableWWW 进行一步网络操作。它的Get/Post函数返回可订阅的IObservables.

ObservableWWW.Get("http://google.co.jp/")
.Subscribe(x=Debug.Log(x.Substring(0,100)),ex=Debug.LogExecption(ex)
);

Rx是可组合也是可以取消的，你可以使用LINQ 查询表达式：

var query=from google in ObservableWWW.Get("http://google.com/")from bing in ObservableWWW.Get("http://bing.com/")from unknow in ObservableWWW(goole+bing)select new {google,bing,unknow};
var cancel=query.Subscribe(x=>Debug.Log(x));cancel.Dispose();

使用Observable.WhenAll 执行并行请求（parallel）:

var parallel=Observable.WhenAll(ObservableWWW.Get("http://google.com/"),ObservableWWW.Get("http://bing.com/"),ObservableWWW.Get("http://unity3d.com/")
);
parallel.Subscribe(xs=>{Debug.Log(xs[0].Substring(0,100));// googleDebug.Log(xs[1].Substring(0,100));// bingDebug.Log(xs[2].Substring(0,100));// unity
});

提供进度信息：

// notifier for progress use ScheduledNotifier or new Progress<float>(/* action */)
var progressNotifier=new ScheduledNotifier<float>();
// pass notifier to WWW.Get/Post
progressNotifier.Subscribe(x=>Debug.Log(x));

错误处理：

// If WWW has .error, ObservableWWW throws WWWErrorException to onError pipeline.
// WWWErrorException has RawErrorMessage, HasResponse, StatusCode, ResponseHeaders
ObservableWWW.Get("http://www.google.com/404").CatchIgnore((WWWErrorException ex) =>{Debug.Log(ex.RawErrorMessage);if (ex.HasResponse){Debug.Log(ex.StatusCode);}foreach (var item in ex.ResponseHeaders){Debug.Log(item.Key + ":" + item.Value);}}).Subscribe();

使用IEnumators (Coroutines)

IEnumator(Coroutine)是Unity的基本异步工具，UniRx集成了协程和IObservables,你可以在协程中写异步代码，并使用UniRx编排他们。这是控制异步流最好的方式。

// two coroutines
IEnumerator AsyncA()
{Debug.Log("a start");yield return new WaitForSeconds(1);Debug.Log("a end");
}IEnumerator AsyncB()
{Debug.Log("b start");yield return new WaitForEndOfFrame();Debug.Log("b end");
}
// main code
// Observable.FromCoroutine converts IEnumerator to Observable<Unit>.
// You can also use the shorthand, AsyncA().ToObservable()// after AsyncA completes, run AsyncB as a continuous routine.
// UniRx expands SelectMany(IEnumerator) as SelectMany(IEnumerator.ToObservable())
var cancel = Observable.FromCoroutine(AsyncA).SelectMany(AsyncB).Subscribe();// you can stop a coroutine by calling your subscription's Dispose.
cancel.Dispose();

在Unity5.3中，你可以使用ToYieldInstruction将Observable转化为Coroutine:

IEnumerator TestNewCustomYieldInstruction()
{// wait Rx Observable.yield return Observable.Timer(TimeSpan.FromSeconds(1)).ToYieldInstruction();// you can change the scheduler(this is ignore Time.scale)yield return Observable.Timer(TimeSpan.FromSeconds(1), Scheduler.MainThreadIgnoreTimeScale).ToYieldInstruction();// get return value from ObservableYieldInstructionvar o = ObservableWWW.Get("http://unity3d.com/").ToYieldInstruction(throwOnError: false);yield return o;if (o.HasError) { Debug.Log(o.Error.ToString()); }if (o.HasResult) { Debug.Log(o.Result); }// other sample(wait until transform.position.y >= 100) yield return this.transform.ObserveEveryValueChanged(x => x.position).FirstOrDefault(p => p.y >= 100).ToYieldInstruction();
}

通常情况下，当我们想要协程返回一个值时，我们必须使用回调。Observable.FromCoroutine 可以将协程转化为可取消的IObservable[T]。

public static IObservable<string> GetWWW(string url)
{// convert coroutine to IObservablereturn Observable.FromCoroutine<string>((observer, cancellationToken) => GetWWWCore(url, observer, cancellationToken));
}// IObserver is a callback publisher
// Note: IObserver's basic scheme is "OnNext* (OnError | Oncompleted)?"
static IEnumerator GetWWWCore(string url, IObserver<string> observer, CancellationToken cancellationToken)
{var www = new UnityEngine.WWW(url);while (!www.isDone && !cancellationToken.IsCancellationRequested){yield return null;}if (cancellationToken.IsCancellationRequested) yield break;if (www.error != null){observer.OnError(new Exception(www.error));}else{observer.OnNext(www.text);observer.OnCompleted(); // IObserver needs OnCompleted after OnNext!}
}

这还有更多的示例，下方展示多个OnNext的形式：

public static IObservable<float> ToObservable(this UnityEngine.AsyncOperation asyncOperation)
{if (asyncOperation == null) throw new ArgumentNullException("asyncOperation");return Observable.FromCoroutine<float>((observer, cancellationToken) => RunAsyncOperation(asyncOperation, observer, cancellationToken));
}static IEnumerator RunAsyncOperation(UnityEngine.AsyncOperation asyncOperation, IObserver<float> observer, CancellationToken cancellationToken)
{while (!asyncOperation.isDone && !cancellationToken.IsCancellationRequested){observer.OnNext(asyncOperation.progress);yield return null;}if (!cancellationToken.IsCancellationRequested){observer.OnNext(asyncOperation.progress); // push 100%observer.OnCompleted();}
}// usecase
Application.LoadLevelAsync("testscene").ToObservable().Do(x => Debug.Log(x)) // output progress.Last() // last sequence is load completed.Subscribe();

多线程的使用

// Observable.Start is start factory methods on specified scheduler
// default is on ThreadPool
var heavyMethod = Observable.Start(() =>
{// heavy method...System.Threading.Thread.Sleep(TimeSpan.FromSeconds(1));return 10;
});var heavyMethod2 = Observable.Start(() =>
{// heavy method...System.Threading.Thread.Sleep(TimeSpan.FromSeconds(3));return 10;
});// Join and await two other thread values
Observable.WhenAll(heavyMethod, heavyMethod2).ObserveOnMainThread() // return to main thread.Subscribe(xs =>{// Unity can't touch GameObject from other thread// but use ObserveOnMainThread, you can touch GameObject naturally.(GameObject.Find("myGuiText")).guiText.text = xs[0] + ":" + xs[1];});

DefaultScheduler(默认调度器)

UniRx默认是基于时间操作的（Interval、Timer、Buffer(timeSpan)等等）,使用Scheduler.MainThread作为它们的调度器。UniRx中的大多数运算符（Observable.Start除外）都是在单个线程上执行的；因此不需要ObserverOn，并且可以忽略线程安全问题。虽然和标准 .NET 中的Rx实现不同，但是这更符合Unity的环境。
Scheduler.Mainthread的执行受Time.timeScale的影响，如果你想要在执行时忽略TimeScale，你可以使用Scheduler.MainThreadIgnoreTimeScale代替。

MonoBehaviour triggers

UniRx使用UniRx.Triggers处理MonoBehaviour事件：

using UniRx;
using UniRx.Triggers; // need UniRx.Triggers namespacepublic class MyComponent : MonoBehaviour
{void Start(){// Get the plain objectvar cube = GameObject.CreatePrimitive(PrimitiveType.Cube);// Add ObservableXxxTrigger for handle MonoBehaviour's event as Observablecube.AddComponent<ObservableUpdateTrigger>().UpdateAsObservable().SampleFrame(30).Subscribe(x => Debug.Log("cube"), () => Debug.Log("destroy"));// destroy after 3 second:)GameObject.Destroy(cube, 3f);}
}

支持的triggers如列表所示：UniRx.wiki#UniRx.Triggers

通过直接订阅Component/GameObject上的扩展方法返回的Observables(可观察对象)，可以更轻松的处理事件，这些方法被自动注入到ObservableTrigger中（除了ObservableEventTrigger和ObservableStateMachineTrigger）：

using UniRx;
using UniRx.Triggers;
public class DragAndDropOnce:MonoBehaviour{void Start(){this.OnMouseDownAsObservable().SelectMany(_=>this.UpdateAsObservable()).TakeUntil(this.OnMouseUpAsObservable()).Select(_=>Input.mousePosition).Subscribe(x=>Debug.Log(x));}
}

之前版本中UniRx提供了ObservableMonoBehaiour.新版本中以不再对其提供支持，请使用UniRx.Triggers代替。

创建自定义Triggers

将Unity事件转化为Observable（可观察对象）是处理Unity事件最好的方式。如果UniRx提供的标准的triggers不够使用的话，你可以自定义triggers.为了演示，下方提供了一个基于UGUI的LongTap（长按）触发演示：

public class ObservableLongPointerDownTrigger : ObservableTriggerBase, IPointerDownHandler, IPointerUpHandler{public float IntervalSecond=1f;Subject<Unit> onLongPointerDown;float> raiseTime;void Update(){if (raiseTime!=null&&raiseTime<=Time.realtimeSinceStartup){if (onLongPointerDown!=null)onLongPointerDown.OnNext(Unit.Default);raiseTime=null;}}void IPointerDownHandler.OnPointerDown(PointerEventData eventData){raiseTime = Time.realtimeSinceStartup + IntervalSecond;}void IPointerUpHandler.OnPointerUp(PointerEventData eventData){raiseTime = null;}public IObservable<Unit> OnLongPointerDownAsObservable(){return onLongPointerDown ?? (onLongPointerDown = new Subject<Unit>());}protected override void RaiseOnCompletedOnDestroy(){if (onLongPointerDown != null){onLongPointerDown.OnCompleted();}}
}

它的使用像标准triggers一样简单：

var trigger = button.AddComponent<ObservableLongPointerDownTrigger>();
trigger.OnLongPointerDownAsObservable().Subscribe();

Observable 生命周期管理

什么时候调用OnCompleted? 使用UniRx时，必须考虑订阅的生命周期管理。当与GameObject对象相连的游戏对象被销毁时，ObservableTriggers会调用OnCompleted.其它的静态生成器方法（Observable.Timer、Observable.EveryUpdate…等等，并不会自动停止，他们的订阅需要被手动管理。

Rx提供了一些辅助方法，比如，IDisposable.AddTo运行你一次释放多个订阅：

// CompositeDisposable is similar with List<IDisposable>, manage multiple IDisposable
CompositeDisposable disposables = new CompositeDisposable(); // fieldvoid Start()
{Observable.EveryUpdate().Subscribe(x => Debug.Log(x)).AddTo(disposables);
}
void OnTriggerEnter(Collider other)
{// .Clear() => Dispose is called for all inner disposables, and the list is cleared.// .Dispose() => Dispose is called for all inner disposables, and Dispose is called immediately after additional Adds.disposables.Clear();
}

如果你想在GameObject被销毁时自动释放，你可以使用AddTo（GameObject/Component):

void Start(){Observable.IntervalFrame(30).Subscribe(x=Debug.Log(x)).AddTo(this);
}

AddTo可以促进流的自动释放，如果你需要在管道中队OnCompleted进行特殊处理，那么你可以使用TakeWhile、TakeUntil、TakeUntilDestroy和TakeUntilDisable代替：

Observable.IntervalFrame(30).TakeUntilDisable(this).Subscribe(x => Debug.Log(x), () => Debug.Log("completed!"));

当你处理事件时，Repeat是一种重要但危险的方法，它可能会造成程序的无线循环，因此，请谨慎使用它：

using UniRx;
using UniRx.Triggers;
public class DangerousDragAndDrop:MonoBehaviour{void Start(){this.gameObject.OnMouseDownAsObservable().SelectMany(_=>this.gameObject.UpdateAsObservable()).TakeUtil(this.gameObject.OnMouseUpAsObservable()).Select(_=>Input.mousePosition).Repeat().Subscribe(x=>Debug.Log(x));}
}

UniRx另外提供了一种安全使用Repeat的方法。RepeatSafe:
如果重复调用OnComplete,Repeat将会停止。RepeatUntilDestroy(gameObject/component), RepeatUntilDisable(gameObject/component)允许在目标对象被销毁时停止。

this.gameObject.OnMouseDownAsObservable().SelectMany(_ => this.gameObject.UpdateAsObservable()).TakeUntil(this.gameObject.OnMouseUpAsObservable()).Select(_ => Input.mousePosition).RepeatUntilDestroy(this) // safety way.Subscribe(x => Debug.Log(x));

UniRx确保hot Observable(FromEvent/Subject/ReactiveProperty/UnityUI.AsObservable…, 类似事件)可以持续的处理异常。什么意思？如果在Subscribe中订阅，这不分离事件。

button.OnClickAsObservable().Subscribe(_ =>
{// If throws error in inner subscribe, but doesn't detached OnClick event.ObservableWWW.Get("htttp://error/").Subscribe(x =>{Debug.Log(x);});
});

这种行为有时很有用，比如用户事件的处理。

每一个类的实例都提供了一个ObserveEveryValueChanged的方法。这个方法可以每一帧检测某个值发生的变化：

// watch position change
this.transform.ObserveEveryValueChanged(x => x.position).Subscribe(x => Debug.Log(x));

这是非常有用的，如果观察的目标是一个GameObject;当GameObject被销毁时，订阅将自动停止并调用OnCompleted.如果观察的对象是一个原生的C#对象，OnCompleted将在GC时被调用。

将Unity回调转化为IObservables(可观察对象)

使用Subject(或者AsyncSubject进行异步操作)：

public class LogCallback
{public string Condition;public string StackTrace;public UnityEngine.LogType LogType;
}public static class LogHelper
{static Subject<LogCallback> subject;public static IObservable<LogCallback> LogCallbackAsObservable(){if (subject == null){subject = new Subject<LogCallback>();// Publish to Subject in callbackUnityEngine.Application.RegisterLogCallback((condition, stackTrace, type) =>{subject.OnNext(new LogCallback { Condition = condition, StackTrace = stackTrace, LogType = type });});}return subject.AsObservable();}
}// method is separatable and composable
LogHelper.LogCallbackAsObservable().Where(x => x.LogType == LogType.Warning).Subscribe();LogHelper.LogCallbackAsObservable().Where(x => x.LogType == LogType.Error).Subscribe();

Unity5中，Application.RegisterLogCallback被移除了，转而提供Application.logMessageReceived的支持，因此，我们现在可以简单的使用Observable.FromEvent.

public static IObservable<LogCallback> LogCallbackAsObservable()
{return Observable.FromEvent<Application.LogCallback, LogCallback>(h => (condition, stackTrace, type) => h(new LogCallback { Condition = condition, StackTrace = stackTrace, LogType = type }),h => Application.logMessageReceived += h, h => Application.logMessageReceived -= h);
}

Stream Logger

// using UniRx.Diagnostics;// logger is threadsafe, define per class with name.
static readonly Logger logger = new Logger("Sample11");// call once at applicationinit
public static void ApplicationInitialize()
{// Log as Stream, UniRx.Diagnostics.ObservableLogger.Listener is IObservable<LogEntry>// You can subscribe and output to any place.ObservableLogger.Listener.LogToUnityDebug();// for example, filter only Exception and upload to web.// (make custom sink(IObserver<EventEntry>) is better to use)ObservableLogger.Listener.Where(x => x.LogType == LogType.Exception).Subscribe(x =>{// ObservableWWW.Post("", null).Subscribe();});
}// Debug is write only DebugBuild.
logger.Debug("Debug Message");// or other logging methods
logger.Log("Message");
logger.Exception(new Exception("test exception"));

Debugging

UniRx.Diagnostics命名空间下的Debug运算符便于用于调试。

// needs Diagnostics using
using UniRx.Diagnostics;---// [DebugDump, Normal]OnSubscribe
// [DebugDump, Normal]OnNext(1)
// [DebugDump, Normal]OnNext(10)
// [DebugDump, Normal]OnCompleted()
{var subject = new Subject<int>();subject.Debug("DebugDump, Normal").Subscribe();subject.OnNext(1);subject.OnNext(10);subject.OnCompleted();
}// [DebugDump, Cancel]OnSubscribe
// [DebugDump, Cancel]OnNext(1)
// [DebugDump, Cancel]OnCancel
{var subject = new Subject<int>();var d = subject.Debug("DebugDump, Cancel").Subscribe();subject.OnNext(1);d.Dispose();
}// [DebugDump, Error]OnSubscribe
// [DebugDump, Error]OnNext(1)
// [DebugDump, Error]OnError(System.Exception)
{var subject = new Subject<int>();subject.Debug("DebugDump, Error").Subscribe();subject.OnNext(1);subject.OnError(new Exception());
}

在在OnNext，OnError，OnCompleted，OnCancel，OnSubscribe时序上显示序列元素以进行Debug.Log，仅当#if DEBUG时才被启用。

Unity-specific Extra Gems

// Unity's singleton UiThread Queue Scheduler
Scheduler.MainThreadScheduler
ObserveOnMainThread()/SubscribeOnMainThread()// Global StartCoroutine runner
MainThreadDispatcher.StartCoroutine(enumerator)// convert Coroutine to IObservable
Observable.FromCoroutine((observer, token) => enumerator(observer, token)); // convert IObservable to Coroutine
yield return Observable.Range(1, 10).ToYieldInstruction(); // after Unity 5.3, before can use StartAsCoroutine()// Lifetime hooks
Observable.EveryApplicationPause();
Observable.EveryApplicationFocus();
Observable.OnceApplicationQuit();

FrameCount-based timeoperators

UniRx 提供了一些继续帧数的时间运算符

Method
EveryUpdate
EevryFixedUpdate
EveryEndOfFrame
EveryGameObjectUpdate
EveryLateUpdate
ObserveOnMainThread
NextFrame
IntervalFrame
TimerFrame
DelayFrame
SampleFrame
ThrottleFrame
ThrottleFirstFrame
TimeoutFrame
DelayFrameSubscription
FrameInterval
FrameTimeInterval
BatchFrame

例如，一次延时调用：

Observable.TimerFrame(100).Subscribe(_ => Debug.Log("after 100 frame"));

Every* 方法的执行顺序如下：

EveryGameObjectUpdate(in MainThreadDispatcher's Execution Order) ->
EveryUpdate ->
EveryLateUpdate ->
EveryEndOfFrame

如果在MainThreadDispatcher之前调用了调用者，则从同一帧调用EveryGameObjectUpdate.(我建议对MainThreadDispatcher的调用在同一帧中优先于EveryLateUpdate、EveryEndOfFrame)，EveryUpdate在下一帧中调用。

MicroCoroutine(微协程)

微协程的优点在于内存高效和执行快速。它的实现是基于Unity blog’s 10000 UPDATE() CALLS，避免了托管内存-非托管内存的开销，以致迭代速度提升了10倍。微协程自动用于基于帧数的时间运算符和ObserveEveryValueChanged.

如果你想使用微协程替代Unity自带的协程（Coroutine）,使用MainThreadDispatcher.StartUpdateMicroCoroutine 或者Observable.FromMicroCoroutine.

int counter;IEnumerator Worker()
{while(true){counter++;yield return null;}
}void Start()
{for(var i = 0; i < 10000; i++){// fast, memory efficientMainThreadDispatcher.StartUpdateMicroCoroutine(Worker());// slow...// StartCoroutine(Worker());}
}

当然微协程存在一些限制，经支持yield return null 迭代，并且其更新时间取决于启动微协程的方法（StartUpdateMicroCoroutine，StartFixedUpdateMicroCoroutine，StartEndOfFrameMicroCoroutine）。

如果和其它IObservable结合起来，你可以检测已完成的属性，比如：isDone.

IEnumerator MicroCoroutineWithToYieldInstruction()
{var www = ObservableWWW.Get("http://aaa").ToYieldInstruction();while (!www.IsDone){yield return null;}if (www.HasResult){UnityEngine.Debug.Log(www.Result);}
}

UGUI 集成

UniRx可以很容易的处理UnityEvent,使用UnityEvent.AsObservable 订阅事件：

public Button MyButton;
// ---
MyButton.onClick.AsObservable().Subscribe(_ => Debug.Log("clicked"));

将事件视为可观察对象可启用声明式UI编程。

public Toggle MyToggle;
public InputField MyInput;
public Text MyText;
public Slider MySlider;// On Start, you can write reactive rules for declaretive/reactive ui programming
void Start()
{// Toggle, Input etc as Observable (OnValueChangedAsObservable is a helper providing isOn value on subscribe)// SubscribeToInteractable is an Extension Method, same as .interactable = x)MyToggle.OnValueChangedAsObservable().SubscribeToInteractable(MyButton);// Input is displayed after a 1 second delayMyInput.OnValueChangedAsObservable().Where(x => x != null).Delay(TimeSpan.FromSeconds(1)).SubscribeToText(MyText); // SubscribeToText is helper for subscribe to text// Converting for human readabilityMySlider.OnValueChangedAsObservable().SubscribeToText(MyText, x => Math.Round(x, 2).ToString());
}

更多响应式UI编程，请参考Sample12,Sample13和下面的ReactiveProperty部分。

ReactiveProperty,ReactiveCollection

游戏数据通常需要通知，我们应该使用属性和事件回调吗？这样的话，简直太麻烦了，还好UniRx为我们提供了ReactiveProperty,轻量级的属性代理人。

// Reactive Notification Model
public class Enemy
{public ReactiveProperty<long> CurrentHp { get; private set; }public ReactiveProperty<bool> IsDead { get; private set; }public Enemy(int initialHp){// Declarative PropertyCurrentHp = new ReactiveProperty<long>(initialHp);IsDead = CurrentHp.Select(x => x <= 0).ToReactiveProperty();}
}// ---
// onclick, HP decrement
MyButton.OnClickAsObservable().Subscribe(_ => enemy.CurrentHp.Value -= 99);
// subscribe from notification model.
enemy.CurrentHp.SubscribeToText(MyText);
enemy.IsDead.Where(isDead => isDead == true).Subscribe(_ =>{MyButton.interactable = false;});

你可以组合使用UnityEvent.AsObservable返回的ReactiveProperties、ReactuveCollections和Observables.所有的UI元素都可作为可观察对象（Observable）.

泛型ReactiveProperties不能被序列化或者在Unity的Inspecatble中显示。但是UniRx为ReactivePropery提供了专门的子类，诸如 int/LongReactiveProperty,Float/DoubleReactiveProperty,StringReactiveProperty,BoolReactiveProperty 等等。（在这查看：(InspectableReactiveProperty.cs),这些属性都可以在Inspector中编辑，对于你自定义的Enum ReactiveProperty,编写一个自定义的inspectable ReactiveProperty[T]是很容易的。如果你需要为ReactiveProperty增加[Myltiline]或者[Range]之类的属性，你可以使用MultilineReactivePropertyAttribute和RangeReactivePropertyAttribute 替换Unity的Multiline和Range。

所提供的派生自InspecetableReactiveProperty显示在Inspector中，在值发生更改时发出通知，在Inspector中更改值时也会发出通知。

这个功能由 InspectorDisplayDrawer提供，通过继承你可以应用你自己自定义的ReactiveProperty:

public enum Fruit
{Apple, Grape
}[Serializable]
public class FruitReactiveProperty : ReactiveProperty<Fruit>
{public FruitReactiveProperty(){}public FruitReactiveProperty(Fruit initialValue):base(initialValue){}
}[UnityEditor.CustomPropertyDrawer(typeof(FruitReactiveProperty))]
[UnityEditor.CustomPropertyDrawer(typeof(YourSpecializedReactiveProperty2))] // and others...
public class ExtendInspectorDisplayDrawer : InspectorDisplayDrawer
{}

如果ReactiveProperty仅在流中被更新，通过使用ReadOnlyReactiveProperty你可以将属性变为只读的。

public class Person
{public ReactiveProperty<string> GivenName { get; private set; }public ReactiveProperty<string> FamilyName { get; private set; }public ReadOnlyReactiveProperty<string> FullName { get; private set; }public Person(string givenName, string familyName){GivenName = new ReactiveProperty<string>(givenName);FamilyName = new ReactiveProperty<string>(familyName);// If change the givenName or familyName, notify with fullName!FullName = GivenName.CombineLatest(FamilyName, (x, y) => x + " " + y).ToReadOnlyReactiveProperty();}
}

Model-View-(Reactive)Presenter Pattern

UniRx使得MVP(MVRP)模式的实现成为可能。

为什么我们需要使用MVP模式替换MVVM模式。Unity中没有提供UI绑定机制，创建绑定层太过于复杂且会影响性能。尽管如此，视图任然需要更新。Presenter持有视图的组件并能更新视图。虽然不是真正的绑定，但Observables 启用了对通知的订阅，它看起来更真实，这个模式被称为Reactive Presenter.

// Presenter for scene(canvas) root.
public class ReactivePresenter : MonoBehaviour
{// Presenter is aware of its View (binded in the inspector)public Button MyButton;public Toggle MyToggle;// State-Change-Events from Model by ReactivePropertyEnemy enemy = new Enemy(1000);void Start(){// Rx supplies user events from Views and Models in a reactive manner MyButton.OnClickAsObservable().Subscribe(_ => enemy.CurrentHp.Value -= 99);MyToggle.OnValueChangedAsObservable().SubscribeToInteractable(MyButton);// Models notify Presenters via Rx, and Presenters update their viewsenemy.CurrentHp.SubscribeToText(MyText);enemy.IsDead.Where(isDead => isDead == true).Subscribe(_ =>{MyToggle.interactable = MyButton.interactable = false;});}
}// The Model. All property notify when their values change
public class Enemy
{public ReactiveProperty<long> CurrentHp { get; private set; }public ReactiveProperty<bool> IsDead { get; private set; }public Enemy(int initialHp){// Declarative PropertyCurrentHp = new ReactiveProperty<long>(initialHp);IsDead = CurrentHp.Select(x => x <= 0).ToReactiveProperty();}
}

在Unity的Hierarchy中，视图就是一个场景。视图在初始化时有UnityEngine和Presenters关联。xxxAsObservable方法使得创建事件信号变得简单，没有任何开销。SubscribeToText和SubscribeToInteractable是类似绑定的简单的工具。虽然简单，但是非常强大。他们很符合Unity的编程环境，并提供了高性能和简洁的体系结构。

V->RP->M->RP->V以响应式的方式完成的连接起来，UniRx提供了适配的方法和类。当然你也可以使用其它的MVVM(或者MV*) 框架代替，UniRx/ReactiveProperty仅仅是一个简单的工具集。

GUI编程也受益于ObservableTriggers.ObservableTriggers转化Unity事件为Observables(可观察对象)，因此可以使用它们来组成MV®P模式。例如：ObservableEventTrigger 转化UGUI事件为Observable(可观察对象)：

var eventTrigger = this.gameObject.AddComponent<ObservableEventTrigger>();
eventTrigger.OnBeginDragAsObservable().SelectMany(_ => eventTrigger.OnDragAsObservable(), (start, current) => UniRx.Tuple.Create(start, current)).TakeUntil(eventTrigger.OnEndDragAsObservable()).RepeatUntilDestroy(this).Subscribe(x => Debug.Log(x));

ReactiveCommand,AsyncReactiveCommand

ReactiveCommand作为可交互按钮命令的抽象。

public class Player
{       public ReactiveProperty<int> Hp;      public ReactiveCommand Resurrect;       public Player(){        Hp = new ReactiveProperty<int>(1000);        // If dead, can not execute.        Resurrect = Hp.Select(x => x <= 0).ToReactiveCommand();        // Execute when clicked     Resurrect.Subscribe(_ =>        {       Hp.Value = 1000;       });         }
}       public class Presenter : MonoBehaviour
{       public Button resurrectButton;      Player player;      void Start(){       player = new Player();     // If Hp <= 0, can't press button.     player.Resurrect.BindTo(resurrectButton);       }
}

AsyncReactiveCommand 是ReactiveCommand的异步形式，将CanExecute(大多数情况下绑定到按钮的interactable)更改为false，直到异步操作执行完成。

public class Presenter:MonoBehaviour{public UnityEngine.UI.Button button;void Start(){var command=new AsyncReactiveCommand();command.Subscribe(_=>{return Observable.Timer(TimeSpan.FromSeconds(3)).asUnitObservable();});command.BindTo(button);button.BindToOnClick(_=>{return Observable.Timer(TimeSpan.FromSeconds(3)).AsUnitObservable();});}
}

AsyncReactiveCommand 有三个构造函数。

()CanExecute默认为false,直到异步执行完成
(IObservable canExecuteSource) 当canExecuteSource发送true并且不在执行时，与empty混合，CanExecute变为true.
(IReactiveProperty sharedCanExecute) 在多个AsyncReactiveCommands之间共享执行状态，如果其中一个AsyncReactiveCommand正在执行，其它AsyncReactiveCommands(拥有一个sharedCanExecute属性)的CanExecute变为false，直到这个AsyncCommand异步执行完成.

public class Presenter : MonoBehaviour
{public UnityEngine.UI.Button button1;public UnityEngine.UI.Button button2;void Start(){// share canExecute status.// when clicked button1, button1 and button2 was disabled for 3 seconds.var sharedCanExecute = new ReactiveProperty<bool>();button1.BindToOnClick(sharedCanExecute, _ =>{return Observable.Timer(TimeSpan.FromSeconds(3)).AsUnitObservable();});button2.BindToOnClick(sharedCanExecute, _ =>{return Observable.Timer(TimeSpan.FromSeconds(3)).AsUnitObservable();});}
}

MessageBroker, AsyncMessageBroker

MessageBroker基于Rx的内存的pubsub系统的按类型过滤的。

public class TestArgs
{public int Value { get; set; }
}---// Subscribe message on global-scope.
MessageBroker.Default.Receive<TestArgs>().Subscribe(x => UnityEngine.Debug.Log(x));// Publish message
MessageBroker.Default.Publish(new TestArgs { Value = 1000 });

AsyncMessageBroker是MessageBroker的异步形式，可以await发布调用

AsyncMessageBroker.Default.Subscribe<TestArgs>(x =>
{// show after 3 seconds.return Observable.Timer(TimeSpan.FromSeconds(3)).ForEachAsync(_ =>{UnityEngine.Debug.Log(x);});
});AsyncMessageBroker.Default.PublishAsync(new TestArgs { Value = 3000 }).Subscribe(_ =>{UnityEngine.Debug.Log("called all subscriber completed");});

UniRx.ToolKit

UniRx.ToolKit 中包含一些Rx-ish工具。当前版本中包含 ObjectPool(对象池)和AsyncObjectPool(异步对象池)，这个池子在租赁前可以租、回收和异步预加载。

// sample class
public class Foobar : MonoBehaviour
{public IObservable<Unit> ActionAsync(){// heavy, heavy, action...return Observable.Timer(TimeSpan.FromSeconds(3)).AsUnitObservable();}
}public class FoobarPool : ObjectPool<Foobar>
{readonly Foobar prefab;readonly Transform hierarchyParent;public FoobarPool(Foobar prefab, Transform hierarchyParent){this.prefab = prefab;this.hierarchyParent = hierarchyParent;}protected override Foobar CreateInstance(){var foobar = GameObject.Instantiate<Foobar>(prefab);foobar.transform.SetParent(hierarchyParent);return foobar;}// You can overload OnBeforeRent, OnBeforeReturn, OnClear for customize action.// In default, OnBeforeRent = SetActive(true), OnBeforeReturn = SetActive(false)// protected override void OnBeforeRent(Foobar instance)// protected override void OnBeforeReturn(Foobar instance)// protected override void OnClear(Foobar instance)
}public class Presenter : MonoBehaviour
{FoobarPool pool = null;public Foobar prefab;public Button rentButton;void Start(){pool = new FoobarPool(prefab, this.transform);rentButton.OnClickAsObservable().Subscribe(_ =>{var foobar = pool.Rent();foobar.ActionAsync().Subscribe(__ =>{// if action completed, return to poolpool.Return(foobar);});});}
}

Visual Studio Analyzer

对Visual Studio 2015的用户来说，UniRx提供了一个自定义的分析工具————UniRxAnalyzer。例如：检测流什么时候没有被订阅。

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ObservableWWW 在订阅前不会被触发，分析器抛出使用不当的警告，你可以通过NuGet下载它。

Install-Package UniRxAnalyzer

请在github的Issuse中提交你的关于Analyzer的新想法。

案例

看UniRx/Examples

Windows Store/Phone App (NETFX_CORE)

一些接口，例如UniRx.IObservable和System.IObservable ,当提交应用到Windows Store App时会引起冲突，因此，当时用NETFX_CORE时，请不要使用诸如UniRx.IObservable这样的结构，使用其简短的形式，不要添加命名空间，冲突就解决了。

分离DLL

如果你想使用预构建的UniRx,你可以构建自己的dll,克隆这个项目并打开UniRx.sln,你会看到这是一个完全分离的项目。你需要像这样定义编译宏定义UNITY;UNITY_5_4_OR_NEWER;UNITY_5_4_0;UNITY_5_4;UNITY_5; + UNITY_EDITOR, UNITY_IPHONE或者其它平台宏定义，在发布页面我们不提供预编译二进制文件，因为在asset store 中的编译符号各不相同。

参考

UniRx/wiki
UniRx API 文档：
ReactiveX
ReactiveX的主页.介绍，[所有运算符(http://reactivex.io/documentation/operators.html)以图形化的方式来说明和讲解，使得理解起来更加容易。UniRxshReactiveX的官方语言。
Introduction to Rx

非常棒的在线教程和电子书
Beginner’s Guide to the Reactive Extensions

更多Rx的视频、ppt和文档
Reactive Programming, Unity 3D and you
- Repository of UniRxSimpleGame
PPT介绍 By @@torisoup
- Repository of UniRxSimpleGame
PPT介绍和游戏示例 By @Xerios
GDC 2016 Sessions of Adventure Capialist