甘肃城乡建设厅网站首页,企业不想做网站的原因,服务器网站建设软件有哪些,自己做网站设计制作要使用Rxjava首先要导入两个包#xff0c;其中rxandroid是rxjava在android中的扩展 implementation io.reactivex:rxandroid:1.2.1implementation io.reactivex:rxjava:1.2.0observer 是一个观察者接口#xff0c;泛型T为观察者观察数据的类型#xff0c;里面只有三个方法其中rxandroid是rxjava在android中的扩展 implementation io.reactivex:rxandroid:1.2.1implementation io.reactivex:rxjava:1.2.0observer 是一个观察者接口泛型T为观察者观察数据的类型里面只有三个方法其中onError()和onCompleted()最后只能调用其中一个调用了此二方法后onNext()将不会在调用 onNext()方法可以调用0到多次观察到的数据处理在此实现。 /*** Provides a mechanism for receiving push-based notifications.* p* After an Observer calls an {link Observable}s {link Observable#subscribe subscribe} method, the* {code Observable} calls the Observers {link #onNext} method to provide notifications. A well-behaved* {code Observable} will call an Observers {link #onCompleted} method exactly once or the Observers* {link #onError} method exactly once.** see a hrefhttp://reactivex.io/documentation/observable.htmlReactiveX documentation: Observable/a* param T* the type of item the Observer expects to observe*/
public interface ObserverT {/*** Notifies the Observer that the {link Observable} has finished sending push-based notifications.* p* The {link Observable} will not call this method if it calls {link #onError}.*/void onCompleted();/*** Notifies the Observer that the {link Observable} has experienced an error condition.* p* If the {link Observable} calls this method, it will not thereafter call {link #onNext} or* {link #onCompleted}.** param e* the exception encountered by the Observable*/void onError(Throwable e);/*** Provides the Observer with a new item to observe.* p* The {link Observable} may call this method 0 or more times.* p* The {code Observable} will not call this method again after it calls either {link #onCompleted} or* {link #onError}.** param t* the item emitted by the Observable*/void onNext(T t);}
使用Observer接口创建一个观察者 ObserverString observer new ObserverString() {Overridepublic void onCompleted() {ILog.LogDebug(observer onCompleted is come in);}Overridepublic void onError(Throwable e) {ILog.LogDebug(observer onError is come in);}Overridepublic void onNext(String s) {ILog.LogDebug(observer onNext is come in s s);}};Subscriber 为Observer的一个抽象实现类
public abstract class SubscriberT implements ObserverT, Subscription{}使用Subscriber 创建一个观察者 SubscriberString subscriber new SubscriberString() {Overridepublic void onCompleted() {ILog.LogDebug(subscriber onCompleted is come in);}Overridepublic void onError(Throwable e) {ILog.LogDebug(subscriber onError is come in);}Overridepublic void onNext(String s) {ILog.LogDebug(subscriber onNext is come in s s);}Overridepublic void onStart() {super.onStart();}};其中onStart()方法它会在事件还未发送之前被调用可以用于做一些准备工作。例如数据的清零或重置。这是一个可选方法默认情况下它的实现为空。
Observable被观察者也叫事件发生源它决定什么时候触发事件以及触发怎样的事件。
public class ObservableT {
}Observable 可以使用Observable.create()方法创建 ObservableString observable Observable.create(new Observable.OnSubscribeString() {Overridepublic void call(Subscriber? super String subscriber) {subscriber.onNext(observable call onNext0);subscriber.onStart();subscriber.onNext(observable call onNext);subscriber.onCompleted();subscriber.onNext(observable call onNext1);}});也可以使用just和from方法创建
ObservableString observable Observable.just(observable call onNext,observable call onNext1);String[] array {observable call onNext,observable call onNext1};
ObservableString observable2 Observable.from(array);那么just,from之间的区别是什么呢通过查看Observable源码,just方法内部也是调用的from方法。
public class ObservableT {....public static T ObservableT just(T t1, T t2) {return from((T[])new Object[] { t1, t2 });}....
}
观察者和被观察者之间的绑定
observable.subscribe(subscriber);Rxjava的不完整回调Action Action后的数字代表回调的参数类型数量 Action1String onNextAction new Action1String() {Overridepublic void call(String s) {ILog.LogDebug(onNextAction onNext s s);}};Action2String,String action2 new Action2String, String() {Overridepublic void call(String s, String s2) {}};Action1Throwable throwableAction1 new Action1Throwable() {Overridepublic void call(Throwable throwable) {ILog.LogDebug(throwableAction1 call);}};Action0 onCompleteAction new Action0() {Overridepublic void call() {ILog.LogDebug(onCompleteAction is come in);}};//调用方法observable.subscribe(onNextAction);observable.subscribe(onNextAction,throwableAction1);observable.subscribe(onNextAction,throwableAction1,onCompleteAction);那么Rxjava的内部是怎么使用action的呢 通过源码可以看到 public class ObservableT {......public final Subscription subscribe(final Action1? super T onNext, final Action1Throwable onError) {if (onNext null) {throw new IllegalArgumentException(onNext can not be null);}if (onError null) {throw new IllegalArgumentException(onError can not be null);}Action0 onCompleted Actions.empty();return subscribe(new ActionSubscriberT(onNext, onError, onCompleted));}......public final Subscription subscribe(Subscriber? super T subscriber) {return Observable.subscribe(subscriber, this);}......
}
最后调用了 subscribe()方法 而 subscribe()方法参数是Subscriber通过查看ActionSubscriber源码可知还是将action作为参数 最后转成了Subscriber对象
public final class ActionSubscriberT extends SubscriberT {final Action1? super T onNext;final Action1Throwable onError;final Action0 onCompleted;public ActionSubscriber(Action1? super T onNext, Action1Throwable onError, Action0 onCompleted) {this.onNext onNext;this.onError onError;this.onCompleted onCompleted;}Overridepublic void onNext(T t) {onNext.call(t);}Overridepublic void onError(Throwable e) {onError.call(e);}Overridepublic void onCompleted() {onCompleted.call();}
}同理当我们使用Observer接口生成匿名类时然后再调用 observable.subscribe(observer);进行绑定也是将Observer转换成Subscriber对象源代码如下
public class ObservableT {......public final Subscription subscribe(final Observer? super T observer) {if (observer instanceof Subscriber) {return subscribe((Subscriber? super T)observer);}if (observer null) {throw new NullPointerException(observer is null);}return subscribe(new ObserverSubscriberT(observer));}......}public final class ObserverSubscriberT extends SubscriberT {final Observer? super T observer;public ObserverSubscriber(Observer? super T observer) {this.observer observer;}Overridepublic void onNext(T t) {observer.onNext(t);}Overridepublic void onError(Throwable e) {observer.onError(e);}Overridepublic void onCompleted() {observer.onCompleted();}
}
