从普通Java事件创建可观察对象
从经典Java事件模式创建Rx Java从普通Java事件创建可观察对象,java,events,event-handling,rx-java,Java,Events,Event Handling,Rx Java,从经典Java事件模式创建Rx Java可观察的的最佳方法是什么?也就是说 class FooEvent { ... } interface FooListener { void fooHappened(FooEvent arg); } class Bar { public void addFooListener(FooListener l); public void removeFooListener(FooListener l); } 我想实施 Observable<
可观察的
的最佳方法是什么?也就是说
class FooEvent { ... }
interface FooListener {
void fooHappened(FooEvent arg);
}
class Bar {
public void addFooListener(FooListener l);
public void removeFooListener(FooListener l);
}
我想实施
Observable<FooEvent> fooEvents(Bar bar);
可观察事件(条形);
我提出的实施方案是:
Observable<FooEvent> fooEvents(Bar bar) {
return Observable.create(new OnSubscribeFunc<FooEvent>() {
public Subscription onSubscribe(Observer<? super FooEvent> obs) {
FooListener l = new FooListener() {
public void fooHappened(FooEvent arg) {
obs.onNext(arg);
}
};
bar.addFooListener(l);
return new Subscription() {
public void unsubscribe() {
bar.removeFooListener(l);
}
};
}
});
}
可观察事件(条形){
return Observable.create(新建onsubscribeefunc()){
publicsubscriptiononsubscribe(Observer如果你想要一些简单的内置功能,试试这种方法
网站上有一个片段展示了如何使用它
package com.javacodegeeks.snippets.core;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
public class BeanPropertyChangeEventListener {
public static void main(String[] args) throws Exception {
Bean bean = new Bean();
bean.addPropertyChangeListener(new MyPropertyChangeListener());
bean.setProperty1("newProperty1");
bean.setProperty2(123);
bean.setProperty1("newnewProperty1");
bean.setProperty2(234);
}
public static class MyPropertyChangeListener implements PropertyChangeListener {
// This method is called every time the property value is changed
public void propertyChange(PropertyChangeEvent evt) {
System.out.println("Name = " + evt.getPropertyName());
System.out.println("Old Value = " + evt.getOldValue());
System.out.println("New Value = " + evt.getNewValue());
System.out.println("**********************************");
}
}
public static class Bean {
private PropertyChangeSupport pcs = new PropertyChangeSupport(this);
// Property property1
private String property1;
// Property property2
private int property2;
public String getProperty1() {
return property1;
}
public void setProperty1(String property1) {
pcs.firePropertyChange("property1", this.property1, property1);
this.property1 = property1;
}
public int getProperty2() {
return property2;
}
public void setProperty2(int property2) {
pcs.firePropertyChange("property2", this.property2, property2);
this.property2 = property2;
}
public void addPropertyChangeListener(PropertyChangeListener listener) {
pcs.addPropertyChangeListener(listener);
}
}
}
这很简单我不认为有办法为每一个可能的事件创建一个通用的可观察对象,但是你当然可以在任何需要的地方使用它们
RxJava源代码提供了一些方便的示例,说明如何从鼠标事件、按钮事件等创建观察对象。看看这个类,它从KeyEvents创建观察对象:。我想如果您使用另一层监听器作为实际回调和观察者之间的桥梁,您也可以得到同样的结果。实际回调→ 桥回调→ 观察员
好处:
- 更多线性码
- 实际回调的一个实例,在observer之外
- 对于高阶函数,如函数
kotlin中的文字:
Ex(注意创建可观察闭包有多小):
class LocationService@Inject构造函数(私有val-GoogleapClient:GoogleapClient):ConnectionCallbacks{
val locationObservable:可观察的
私有变量passToObservable:(位置?->Unit={}
初始化{
locationObservable=Observable.create{subscription->
passToObservable={location->
subscription.onNext(位置)
}
}doOnSubscribe先生{
GoogleAppClient.registerConnectionCallbacks(此)
GoogleAppClient.connect()
}杜努恩先生{
GoogleAppClient.unregisterConnectionCallbacks(此)
}
}
覆盖未连接的乐趣(连接提示:捆绑?){
val location=LocationServices.FusedLocationApi.getLastLocation(GoogleAppClient)
passToObservable(位置)
}
覆盖连接已挂起(原因:Int){
//...
}
}
您的实现是绝对正确的
太冗长了
使用lambdas(例如RxJava 2)时,它的详细程度要小得多:
我建议看一看(如果您可以将番石榴添加到项目中),为什么不使用默认实现?@RC.guava事件总线在许多方面都很好,但它没有RxJava的调度程序或事件流组合器。@astinx请参阅我对Leonardo Kenji答案的评论。1.我想要一些可以处理任何事件的东西(例如,鼠标单击、重新绘制等)。并非所有事件都是属性更改!2.这种方法必须处理字符串属性名称。如果属性名称更改或删除,则不会出现编译器错误。3.类型不安全(您的侦听器中只会有一个对象
。@AlexeyRomanov这是公平的,但我猜不到,可以吗?:-)我建议您在问题中添加这些限制,这样我们可以更好地帮助您。
package com.javacodegeeks.snippets.core;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
public class BeanPropertyChangeEventListener {
public static void main(String[] args) throws Exception {
Bean bean = new Bean();
bean.addPropertyChangeListener(new MyPropertyChangeListener());
bean.setProperty1("newProperty1");
bean.setProperty2(123);
bean.setProperty1("newnewProperty1");
bean.setProperty2(234);
}
public static class MyPropertyChangeListener implements PropertyChangeListener {
// This method is called every time the property value is changed
public void propertyChange(PropertyChangeEvent evt) {
System.out.println("Name = " + evt.getPropertyName());
System.out.println("Old Value = " + evt.getOldValue());
System.out.println("New Value = " + evt.getNewValue());
System.out.println("**********************************");
}
}
public static class Bean {
private PropertyChangeSupport pcs = new PropertyChangeSupport(this);
// Property property1
private String property1;
// Property property2
private int property2;
public String getProperty1() {
return property1;
}
public void setProperty1(String property1) {
pcs.firePropertyChange("property1", this.property1, property1);
this.property1 = property1;
}
public int getProperty2() {
return property2;
}
public void setProperty2(int property2) {
pcs.firePropertyChange("property2", this.property2, property2);
this.property2 = property2;
}
public void addPropertyChangeListener(PropertyChangeListener listener) {
pcs.addPropertyChangeListener(listener);
}
}
}
class LocationService @Inject constructor(private val googleApiClient: GoogleApiClient) : ConnectionCallbacks{
val locationObservable: Observable<Location>
private var passToObservable: (Location?) -> Unit = {}
init {
locationObservable = Observable.create<Location> { subscription ->
passToObservable = { location ->
subscription.onNext(location)
}
}.doOnSubscribe {
googleApiClient.registerConnectionCallbacks(this)
googleApiClient.connect()
}.doOnUnsubscribe {
googleApiClient.unregisterConnectionCallbacks(this)
}
}
override fun onConnected(connectionHint: Bundle?) {
val location = LocationServices.FusedLocationApi.getLastLocation(googleApiClient)
passToObservable(location)
}
override fun onConnectionSuspended(cause: Int) {
//...
}
}
Observable<FooEvent> fooEvents(Bar bar) {
return Observable.create(emitter -> {
FooListener listener = event -> emitter.onNext(event);
bar.addFooListener(listener);
emitter.setCancellable(() -> bar.removeFooListener(listener));
});
}
fooEvents(bar).share()