RxJava用了一年多，一直cv，没仔细的去学习过。拖到rxjava2都出来了，所以今年的遗愿清单里加上学习rxjava2，半年过去了，做下笔记。
新建了一个javalib的module，添加rxjava的依赖。
compile 'io.reactivex.rxjava2:rxjava:2.1.0'
compile 'io.reactivex.rxjava2:rxandroid:2.0.1'
写一个Observable，然后subscribe，发现多了很多的订阅者。
image.png
先试简单的，
Observable.create(new ObservableOnSubscribe() {
@Override
public void subscribe(@NonNull ObservableEmitter e) throws Exception {
System.out.println("subscribe");
e.onNext(1);
}
}).subscribe(new Consumer() {
@Override
public void accept(@NonNull Integer integer) throws Exception {
System.out.println("accept="+integer);
}
});
image.png
和rxjava1如出一辙。
订阅者只有一个方法，那如果发射异常呢？
Observable.create(new ObservableOnSubscribe() {
@Override
public void subscribe(@NonNull ObservableEmitter e) throws Exception {
System.out.println("发射1");
e.onNext(1);
System.out.println("发射异常");
e.onError(new Throwable("我是异常"));
System.out.println("发射异常后");
}
}).subscribe(new Consumer() {
@Override
public void accept(@NonNull Integer integer) throws Exception {
System.out.println("accept="+integer);
}
});
结果就报异常了。accept方法并没有走。so，如果只关心onNext，可以这样写，但是，我们实际工作种要考虑异常情况。那么
Observable.create(new ObservableOnSubscribe() {
@Override
public void subscribe(@NonNull ObservableEmitter e) throws Exception {
System.out.println("发射1");
e.onNext(1);
System.out.println("发射异常");
e.onError(new Throwable("我是异常"));
System.out.println("发射异常后");
}
}).subscribe(new Observer() {
@Override
public void onSubscribe(@NonNull Disposable d) {
System.out.println("onSubscribe");
}
@Override
public void onNext(@NonNull Integer integer) {
System.out.println("onNext" + integer);
}
@Override
public void onError(@NonNull Throwable e) {
System.out.println("onError");
}
@Override
public void onComplete() {
System.out.println("onComplete");
}
});
---------------------------------------------
onSubscribe
发射1
onNext1
发射异常
onError
发射异常后
这些生产者和消费者都是再主线程的,如果在Android里生产数据超时，就引起ANR,那么试一下线程调度：
Observable.create(new ObservableOnSubscribe() {
@Override
public void subscribe(@NonNull ObservableEmitter e) throws Exception {
System.out.println("shot1==thread=="+Thread.currentThread().getName());
e.onNext(1);
System.out.println("shot==thread=="+Thread.currentThread().getName());
e.onError(new Throwable("shoterror"));
System.out.println("aftershoterror==thread=="+Thread.currentThread().getName());
}
}).subscribeOn(Schedulers.io()).subscribe(new Observer() {
@Override
public void onSubscribe(@NonNull Disposable d) {
System.out.println("onSubscribe==thread=="+Thread.currentThread().getName());
}
@Override
public void onNext(@NonNull Integer integer) {
System.out.println("onNext" + integer+"==thread=="+Thread.currentThread().getName());
}
@Override
public void onError(@NonNull Throwable e) {
System.out.println("onError==thread=="+Thread.currentThread().getName());
}
@Override
public void onComplete() {
System.out.println("onComplete"+Thread.currentThread().getName());
}
});
System.out.println("aaaaaaaaaaa==thread==" +Thread.currentThread().getName());
image.png
.subscribeOn(Schedulers.io())后，生产消费都在io线程。
@Override
public void onSubscribe(@NonNull Disposable d) {
System.out.println("onSubscribe==thread=="+Thread.currentThread().getName());
}
这个方法是在main线程，因为这个是在订阅前的线程，就是 Observable.create的时候的线程。
Observable.create(new ObservableOnSubscribe() {
@Override
public void subscribe(@NonNull ObservableEmitter e) throws Exception {
System.out.println("shot1==thread==" + Thread.currentThread().getName());
e.onNext(1);
System.out.println("shot==thread==" + Thread.currentThread().getName());
e.onError(new Throwable("shoterror"));
System.out.println("aftershoterror==thread==" + Thread.currentThread().getName());
}
}).subscribeOn(Schedulers.io())
.subscribeOn(Schedulers.io()).subscribe(new Observer() {
@Override
public void onSubscribe(@NonNull Disposable d) {
System.out.println("onSubscribe==thread==" + Thread.currentThread().getName());
}
@Override
public void onNext(@NonNull Integer integer) {
System.out.println("onNext" + integer + "==thread==" + Thread.currentThread().getName());
}
@Override
public void onError(@NonNull Throwable e) {
System.out.println("onError==thread==" + Thread.currentThread().getName());
}
@Override
public void onComplete() {
System.out.println("onComplete" + Thread.currentThread().getName());
}
});
System.out.println("aaaaaaaaaaa==thread==" + Thread.currentThread().getName());
如果我.subscribeOn(Schedulers.io())变换2次线程，结果还是第一次的线程。
image.png
)
Observable.create(new ObservableOnSubscribe() {
@Override
public void subscribe(@NonNull ObservableEmitter e) throws Exception {
System.out.println("发射1==thread==" + Thread.currentThread().getName());
e.onNext(1);
System.out.println("发射2==thread==" + Thread.currentThread().getName());
e.onNext(2);
System.out.println("发射error==thread==" + Thread.currentThread().getName());
// e.onError(new Throwable("shoterror"));
System.out.println("发射error后==thread==" + Thread.currentThread().getName());
}
}).subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread())
.subscribe(new Observer() {
@Override
public void onSubscribe(@NonNull Disposable d) {
System.out.println("onSubscribe==thread==" + Thread.currentThread().getName());
}
@Override
public void onNext(@NonNull Integer integer) {
System.out.println("onNext" + integer + "==thread==" + Thread.currentThread().getName());
}
@Override
public void onError(@NonNull Throwable e) {
System.out.println("onError==thread==" + Thread.currentThread().getName());
}
@Override
public void onComplete() {
System.out.println("onComplete" + Thread.currentThread().getName());
}
});
.subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread())，subscribeOn是生产发射的线程，observeOn决定的是接收消费的线程。
image.png
如果生产2个数据，打印出来是2个都发射后才消费。顺序是这样的吗？验证：
Observable.create(new ObservableOnSubscribe() {
@Override
public void subscribe(@NonNull ObservableEmitter e) throws Exception {
for (int i = 0; i <1000 ; i++) {
System.out.println(i+"要发射==thread==" + Thread.currentThread().getName());
e.onNext(i);
}
}
})
image.png
确实如此，全部数据发射完后才接受，那么去掉线程调度呢
image.png
生产一个消费一个。