RxJava 在 GitHub 主页上的自我介绍是 "a library for composing asynchronous and event-based programs using observable sequences for the Java VM"（一个在 Java VM 上使用可观测的序列来组成异步的、基于事件的程序的库）。
最简单的使用：
Observable.create(new ObservableOnSubscribe<String>() {
@Override
public void subscribe(ObservableEmitter<String> emitter) throws Exception {
emitter.onNext("第一条");
emitter.onNext("第二条");
emitter.onComplete();
// emitter.onError(new Exception("ssfas"));
}
}).subscribe(new Observer<String>() {
@Override
public void onSubscribe(Disposable d) {
Log.i(TAG,"--------onSubscribe------");
}
@Override
public void onNext(String s) {
Log.i(TAG,"--------onNext------："+s);
}
@Override
public void onError(Throwable e) {
Log.i(TAG,"--------onError------");
}
@Override
public void onComplete() {
Log.i(TAG,"--------onComplete------");
}
});
Flowable：
/**
* BackpressureStrategy.ERROR----128
* BackpressureStrategy.BUFFE----无限制
* BackpressureStrategy.DROP-----丢弃保存不了的--128
* BackpressureStrategy.LATEST---保留最新的-----128
* 对应的方法：
* onBackpressureBuffer()
* onBackpressureDrop()
* onBackpressureLatest()
*
*/
Flowable<String> flowable=Flowable.create(new FlowableOnSubscribe<String>() {
@Override
public void subscribe(FlowableEmitter<String> emitter) throws Exception {
emitter.onNext("111111111111");
emitter.onNext("2222222222222");
emitter.onNext("3333333333333");
emitter.onNext("4444444444444");
emitter.onComplete();
}
}, BackpressureStrategy.ERROR);
Subscriber<String> subscriber=new Subscriber<String>() {
@Override
public void onSubscribe(Subscription s) {
Log.i(TAG,"---onSubscribe---");
s.request(Long.MAX_VALUE);
}
@Override
public void onNext(String s) {
Log.i(TAG,s);
}
@Override
public void onError(Throwable t) {
Log.i(TAG,"---onError---");
}
@Override
public void onComplete() {
Log.i(TAG,"---onComplete---");
}
};
flowable.subscribe(subscriber);
线程切换：
Observer<String> observer=new Observer<String>() {
@Override
public void onSubscribe(Disposable d) {
Log.i(TAG,"--------onSubscribe------："+Thread.currentThread().getName());
compositeDisposable.add(d);
}
@Override
public void onNext(String s) {
Log.i(TAG,"--------onNext------："+Thread.currentThread().getName());
}
@Override
public void onError(Throwable e) {
Log.i(TAG,"--------onError------");
}
@Override
public void onComplete() {
Log.i(TAG,"--------onComplete------"+Thread.currentThread().getName());
}
};
Observable<String> observable=Observable.create(new ObservableOnSubscribe<String>() {
@Override
public void subscribe(ObservableEmitter<String> emitter) throws Exception {
Log.i(TAG,"--------Observable------"+Thread.currentThread().getName());
emitter.onNext("第一条");
emitter.onComplete();
}
});
observable.subscribeOn(Schedulers.computation())//1、Schedulers.newThread()2、Schedulers.io()3、Schedulers.computation()
.observeOn(AndroidSchedulers.mainThread())//android自带的主线程
.subscribe(observer);
map操作符：
转换操作符，例如本例子中，将int转化为String打印
Observable.create(new ObservableOnSubscribe<Integer>() {
@Override
public void subscribe(ObservableEmitter<Integer> emitter) throws Exception {
emitter.onNext(1);
emitter.onNext(2);
emitter.onNext(3);
}
}).map(new Function<Integer, String>() {
@Override
public String apply(Integer integer) throws Exception {
return "这是第："+integer+"个指令";
}
}).subscribe(new Observer<String>() {
@Override
public void onSubscribe(Disposable d) {
}
@Override
public void onNext(String s) {
Log.i(TAG,s);
}
@Override
public void onError(Throwable e) {
}
@Override
public void onComplete() {
}
});
flatMap操作符：
这个操作符其实就是再发送一个Observable，举个简单的例子，比如注册后需要登陆就可以用这个操作符
final String[][] name={{"111","1111","11111"},
{"222","2222","22222"},
{"333","3333","33333"}};
Observable.fromArray(name).flatMap(new Function<String[], ObservableSource<?>>() {
@Override
public ObservableSource<?> apply(String[] str) throws Exception {
return Observable.fromArray(str);
};
}).subscribe(new Observer<Object>() {
@Override
public void onSubscribe(Disposable d) {
}
@Override
public void onNext(Object o) {
Log.i(TAG,(String)o);
}
@Override
public void onError(Throwable e) {
}
@Override
public void onComplete() {
}
});
filter操作符：
过滤事件，Observer中只处理filter中返回true的事件
Observable.create(new ObservableOnSubscribe<Integer>() {
@Override
public void subscribe(ObservableEmitter<Integer> emitter) throws Exception {
for (int i=0;i<100;i++){
emitter.onNext(i);
}
}
}).filter(new Predicate<Integer>() {
@Override
public boolean test(Integer integer) throws Exception {
return integer%10==0;
}
}).subscribe(new Observer<Integer>() {
@Override
public void onSubscribe(Disposable d) {
}
@Override
public void onNext(Integer integer) {
Log.i(TAG,"筛选后数据为："+integer);
}
@Override
public void onError(Throwable e) {
}
@Override
public void onComplete() {
}
});
zip操作符：
组合两个发送的事件
Observable<String> observable1=Observable.create(new ObservableOnSubscribe<String>() {
@Override
public void subscribe(ObservableEmitter<String> emitter) throws Exception {
emitter.onNext("111");
emitter.onNext("222");
emitter.onNext("333");
emitter.onComplete();
}
}).subscribeOn(Schedulers.newThread());
Observable<String> observable2=Observable.create(new ObservableOnSubscribe<String>() {
@Override
public void subscribe(ObservableEmitter<String> emitter) throws Exception {
emitter.onNext("AAA");
emitter.onNext("BBB");
emitter.onNext("CCC");
emitter.onNext("DDD");
emitter.onComplete();
}
}).subscribeOn(Schedulers.newThread());
Observable.zip(observable1, observable2, new BiFunction<String, String, String>() {
@Override
public String apply(String s, String s2) throws Exception {
return s+s2;
}
}).subscribe(new Observer<String>() {
@Override
public void onSubscribe(Disposable d) {
}
@Override
public void onNext(String s) {
Log.i(TAG,s);
}
@Override
public void onError(Throwable e) {
}
@Override
public void onComplete() {
Log.i(TAG,"-------complete---------");
}
});
其他简单介绍：
concat：同样是组合连个发送observable，但和zip不同，比如发送事件1,发送的是1,2,3 发送事件2,发送的是a,b,c，则zip的结果是1a,2b,3c ，而concat的结果是1,2,3,a,b,c
concatMap：和flatMap功能相同，但concatMap是有序的，而flatMap则是无序的
distinct：过滤掉相同的事件
timer：表示过多久会执行，只执行一次
interval:定时任务，表示没过多久就会执行一次