RXJava
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1、merge操作符,合并观察对象
@Test public void testMerge() { List<String> list1 = new ArrayList<>(); List<String> list2 = new ArrayList<>(); list1.add("1"); list1.add("2"); list1.add("3"); list2.add("a"); list2.add("b"); list2.add("c"); Observable observable1 = Observable.from(list1); Observable observable2 = Observable.from(list2); //合并数据 先发送observable2的全部数据,然后发送 observable1的全部数据 Observable observable = Observable.merge(observable2, observable1); observable.subscribe(new Action1() { @Override public void call(Object o) { Log.i("lxm", "rx-- " + o); } }); }
2、zip 操作符,合并多个观察对象的数据。并且允许 Func2()函数重新发送合并后的数据
@Test public void testZip() { List<String> list1 = new ArrayList<>(); List<String> list2 = new ArrayList<>(); list1.add("1"); list1.add("2"); list1.add("3"); list2.add("a"); list2.add("b"); list2.add("c"); list2.add("d"); Observable observable1 = Observable.from(list1); Observable observable2 = Observable.from(list2); Observable observable3 = Observable.zip(observable1, observable2, new Func2<String, String, String>() { @Override public String call(String s1, String s2) { return s1 + s2; } }); observable3.subscribe(new Action1() { @Override public void call(Object o) { Log.i("lxm", "zip-- " + o); } }); }
3、scan累加器操作符的使用
@Test public void testScan() { Observable observable = Observable.just(1, 2, 3, 4, 5); observable.scan(new Func2<Integer, Integer, Integer>() { @Override public Integer call(Integer o, Integer o2) { return o + o2; } }).subscribe(new Action1() { @Override public void call(Object o) { Log.i("lxm", "scan-- " + o); } }); }
4、filter 过滤操作符的使用
@Test public void testFilter() { Observable observable = Observable.just(1, 2, 3, 4, 5, 6, 7); observable.filter(new Func1<Integer, Boolean>() { @Override public Boolean call(Integer o) { //数据大于4的时候才会被发送 return o > 4; } }).subscribe(new Action1() { @Override public void call(Object o) { Log.i("lxm", "filter-- " + o); } }); }
5、 消息数量过滤操作符的使用
// take :取前n个数据
// takeLast:取后n个数据
// first 只发送第一个数据
// last 只发送最后一个数据
// skip() 跳过前n个数据发送后面的数据
// skipLast() 跳过最后n个数据,发送前面的数据
@Test public void testTake() { //take 发送前3个数据 Observable observable = Observable.just(1, 2, 3, 4, 5, 6, 7); observable.take(3) .subscribe(new Action1() { @Override public void call(Object o) { System.out.println("take-- " + o); Log.i("lxm", "take-- " + o); } }); //takeLast 发送最后三个数据 Observable observable2 = Observable.just(1, 2, 3, 4, 5, 6, 7); observable2.takeLast(3) .subscribe(new Action1() { @Override public void call(Object o) { System.out.println("takeLast-- " + o); Log.i("lxm", "takeLast-- " + o); } }); //first 只发送第一个数据 Observable observable3 = Observable.just(1, 2, 3, 4, 5, 6, 7); observable3.first() .subscribe(new Action1() { @Override public void call(Object o) { System.out.println("first-- " + o); Log.i("lxm", "first-- " + o); } }); //last 只发送最后一个数据 Observable observable4 = Observable.just(1, 2, 3, 4, 5, 6, 7); observable4.last() .subscribe(new Action1() { @Override public void call(Object o) { System.out.println("last-- " + o); Log.i("lxm", "last-- " + o); } }); //skip() 跳过前2个数据发送后面的数据 Observable observable5 = Observable.just(1, 2, 3, 4, 5, 6, 7); observable5.skip(2) .subscribe(new Action1() { @Override public void call(Object o) { System.out.println("skip-- " + o); Log.i("lxm", "skip-- " + o); } }); //skipLast() 跳过最后两个数据,发送前面的数据 Observable observable6 = Observable.just(1, 2, 3, 4, 5, 6, 7); observable6.skipLast(2) .subscribe(new Action1() { @Override public void call(Object o) { System.out.println("skipLast-- " + o); Log.i("lxm", "skipLast-- " + o); } }); }
6、elementAt 、elementAtOrDefault
@Test public void testElement() { //elementAt() 发送数据序列中第n个数据 ,序列号从0开始 //如果该序号大于数据序列中的最大序列号,则会抛出异常,程序崩溃 //所以在用elementAt操作符的时候,要注意判断发送的数据序列号是否越界 Observable observable7 = Observable.just(1, 2, 3, 4, 5, 6, 7); observable7.elementAt(3) .subscribe(new Action1() { @Override public void call(Object o) { System.out.println("elementAt-- " + o); Log.i("lxm", "elementAt-- " + o); } }); //elementAtOrDefault( int n , Object default ) 发送数据序列中第n个数据 ,序列号从0开始。 //如果序列中没有该序列号,则发送默认值 Observable observable9 = Observable.just(1, 2, 3, 4, 5); observable9.elementAtOrDefault(0, 666) .subscribe(new Action1() { @Override public void call(Object o) { System.out.println("elementAtOrDefault-- " + o); Log.i("lxm", "elementAtOrDefault-- " + o); } }); }
7、startWith() 插入数据
@Test public void testStartWith() {//插入普通数据//startWith 数据序列的开头插入一条指定的项 , 最多插入9条数据 Observable observable = Observable.just("aa", "bb", "cc"); observable .startWith("11", "22") .subscribe(new Action1() { @Override public void call(Object o) { System.out.println("startWith-- " + o); Log.i("lxm", "startWith-- " + o); } });//插入Observable对象 List<String> list = new ArrayList<>(); list.add("ww"); list.add("tt"); observable.startWith(Observable.from(list)) .subscribe(new Action1() { @Override public void call(Object o) { System.out.println("startWith2 -- " + o); Log.i("lxm", "startWith2-- " + o); } }); }
8. delay操作符,延迟数据发送
@Test public void testDelay() { Observable<String> observable = Observable.just("1", "2", "3", "4", "5", "6", "7", "8"); //延迟数据发射的时间,仅仅延时一次,也就是发射第一个数据前延时。发射后面的数据不延时 observable.delay(3, TimeUnit.SECONDS) //延迟3秒钟 .subscribe(new Action1() { @Override public void call(Object o) { Log.i("lxm", "delay-- " + o); } }); try { Thread.sleep(10 * 1000); } catch (InterruptedException e) { e.printStackTrace(); } }
7.定时器
@Test public void testTimer() { //5秒后输出 hello world , 然后显示一张图片 Observable.timer(5, TimeUnit.SECONDS) .observeOn(AndroidSchedulers.mainThread()) .subscribe(new Action1<Long>() { @Override public void call(Long aLong) { System.out.println("timer--hello world " + aLong); Log.i("lxm", "timer ---" + aLong); } }); try { Thread.sleep(10 * 1000); } catch (InterruptedException e) { e.printStackTrace(); } }
8.testInterval
@Test public void testInterval() { //参数一:延迟时间 参数二:间隔时间 参数三:时间颗粒度 Observable observable = Observable.interval(3000, 3000, TimeUnit.MILLISECONDS); Subscription subscription = observable.subscribe(new Action1() { @Override public void call(Object o) { System.out.println("interval- " + o); Log.i("lxm", "interval"); } }); }
9、doOnNext() 操作符,在每次 OnNext() 方法被调用前执行
@Test public void testDoNext() { Observable observable = Observable.just("1", "2", "3", "4"); observable.doOnNext(new Action1() { @Override public void call(Object o) { System.out.println("doOnNext--缓存数据" + o); Log.i("lxm", "doOnNext--缓存数据" + o); } }).subscribe(new Observer() { @Override public void onCompleted() { Log.i("lxm", "onCompleted--"); } @Override public void onError(Throwable e) { Log.i("lxm", "onError--"); } @Override public void onNext(Object o) { System.out.println("onNext--" + o); Log.i("lxm", "onNext--" + o); } }); }
10、Buffer 操作符
//
// Buffer( int n ) 把n个数据打成一个list包,然后再次发送。
// Buffer( int n , int skip) 把n个数据打成一个list包,然后跳过第skip个数据。
// 使用场景:一个按钮每点击3次,弹出一个toast
@Test public void testBuffer() { List<String> list = new ArrayList<>(); for (int i = 1; i < 10; i++) { list.add("" + i); } Observable<String> observable = Observable.from(list); observable .buffer(2) //把每两个数据为一组打成一个包,然后发送 .subscribe(new Action1<List<String>>() { @Override public void call(List<String> strings) { System.out.println("buffer---------------"); Log.i("lxm", "buffer....."); Observable.from(strings).subscribe(new Action1<String>() { @Override public void call(String s) { System.out.println("buffer data --" + s); Log.i("lxm", "buffer data --" + s); } }); } }); }
11、throttleFirst 操作符
// 在一段时间内,只取第一个事件,然后其他事件都丢弃。
// 使用场景:1、button按钮防抖操作,防连续点击 2、百度关键词联想,在一段时间内只联想一次,防止频繁请求服务器
// 这段代码,是循环发送数据,每秒发送一个。throttleFirst( 3 , TimeUnit.SECONDS ) 在3秒内只取第一个事件,其他的事件丢弃。
@Test public void testThrottleFirst() { Observable.interval(1, TimeUnit.SECONDS) .throttleFirst(3, TimeUnit.SECONDS) .subscribe(new Action1<Long>() { @Override public void call(Long aLong) { System.out.println("throttleFirst--" + aLong); Log.i("lxm", "throttleFirst --" + aLong); } }); try { Thread.sleep(10000); } catch (InterruptedException e) { e.printStackTrace(); } }
14、distinct 过滤重复的数据
@Test public void testDistinct() { List<String> list = new ArrayList<>(); list.add("1"); list.add("2"); list.add("1"); list.add("3"); list.add("4"); list.add("2"); list.add("1"); list.add("1"); Observable.from(list) .distinct() .subscribe(new Action1<String>() { @Override public void call(String s) { System.out.println("distinct--" + s); Log.i("lxm", "distinct --" + s); } }); }
15. distinctUntilChanged() 过滤连续重复的数据
@Test public void testDistinctUntilChanged() { List<String> list = new ArrayList<>(); list.add("1"); list.add("2"); list.add("1"); list.add("3"); list.add("4"); list.add("4"); list.add("2"); list.add("1"); list.add("1"); Observable.from(list) .distinctUntilChanged() .subscribe(new Action1<String>() { @Override public void call(String s) { System.out.println("distinctUntilChanged--" + s); Log.i("lxm", "distinctUntilChanged --" + s); } }); }
16.DoOnSubscribe()
@Test public void testDoOnSubscribe() {// doOnSubscribe()// 使用场景: 可以在事件发出之前做一些初始化的工作,比如弹出进度条等等// 注意:// 1、doOnSubscribe() 默认运行在事件产生的线程里面,然而事件产生的线程一般都会运行在 io 线程里。那么这个时候做一些,更新UI的操作,是线程不安全的。//// 所以如果事件产生的线程是io线程,但是我们又要在doOnSubscribe() 更新UI , 这时候就需要线程切换。//// 2、如果在 doOnSubscribe() 之后有 subscribeOn() 的话,它将执行在离它最近的 subscribeOn() 所指定的线程。//// 3、 subscribeOn() 事件产生的线程 ; observeOn() : 事件消费的线程 Observable.just("1111", "2222", "3333").create(new Observable.OnSubscribe<String>() { @Override public void call(Subscriber<? super String> subscriber) { Log.i("lxm", "....."); } }).doOnSubscribe(new Action0() { @Override public void call() { Log.i("lxm", "call"); } }).subscribeOn(Schedulers.io()) .subscribeOn(AndroidSchedulers.mainThread()) // 指定主线程 .observeOn(AndroidSchedulers.mainThread()) .subscribe(new Action1<String>() { @Override public void call(String s) { Log.i("lxm", "xxxxx = " + s); } }); }
17.Range
@Test public void testRange() { Observable.range(10, 20) .subscribe(new Action1<Integer>() { @Override public void call(Integer integer) { Log.i("lxm", "" + integer); } }); }
18.map
@Test public void testMap() { List<Course> courses = new ArrayList<>(); courses.add(new Course("course111", "000000001")); courses.add(new Course("course222", "000000002")); courses.add(new Course("course333", "000000003")); courses.add(new Course("course444", "000000004")); Student[] students = {new Student("1111", "0001", 20, courses), new Student("2222", "0002", 21, courses), new Student("3333", "0003", 22, courses), new Student("4444", "0004", 23, courses)}; Observable.from(students) .map(new Func1<Student, List<Course>>() { @Override public List<Course> call(Student student) { Log.i("lxm", "student=" + student.getName()); return student.getCourse(); } }) //被观察者处于新io线程// .subscribeOn(Schedulers.io()) //观察者处于主线程// .observeOn(AndroidSchedulers.mainThread()) .subscribe(new Action1<List<Course>>() { @Override public void call(List<Course> courses) { Log.i("lxm", "course size = " + courses.size()); for (int i = 0; i < courses.size(); i++) { Log.i("lxm", "观察者:" + courses.get(i).getCourseId() + ":" + courses.get(i).getCourseName()); } } }); }
19.flatMap
@Test public void testFlatMap() { List<Course> courses = new ArrayList<>(); courses.add(new Course("course111", "000000001")); courses.add(new Course("course222", "000000002")); courses.add(new Course("course333", "000000003")); courses.add(new Course("course444", "000000004")); Student[] students = {new Student("1111", "0001", 20, courses), new Student("2222", "0002", 21, courses), new Student("3333", "0003", 22, courses), new Student("4444", "0004", 23, courses)}; Observable.from(students) .flatMap(new Func1<Student, Observable<Course>>() { @Override public Observable<Course> call(Student student) { return Observable.from(student.getCourse()); } }) .subscribe(new Action1<Course>() { @Override public void call(Course course) { Log.i("lxm", "course = " + course.getCourseName()); } }); }
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