过滤操作

1.过滤操作

filter( ) — 过滤数据

Observable.just(1,2,3,4,5,6)        .filter(newFunc1() {@OverridepublicBooleancall(Integer integer){//从数组中，筛选偶数returninteger %2==0;            }        }).subscribe(newAction1() {@Overridepublicvoidcall(Integer i){                Log.d("RxJava", String.valueOf(i));        }});

结果：

11-06 03:42:04.747 4213-4213/? D/RxJava: 211-06 03:42:04.747 4213-4213/? D/RxJava: 411-06 03:42:04.747 4213-4213/? D/RxJava: 6

takeLast( ) — 只发射最后的N项数据

Observable.just(1,2,3,4,5,6)        .takeLast(3)//取最后3项数据.subscribe(newAction1() {@Overridepublicvoidcall(Integer i){                Log.d("RxJava", String.valueOf(i));            }        });

结果：

11-06 03:44:18.307 6379-6379/keye.com.rxjavaobserver D/RxJava: 411-06 03:44:18.307 6379-6379/keye.com.rxjavaobserver D/RxJava: 511-06 03:44:18.307 6379-6379/keye.com.rxjavaobserver D/RxJava: 6

last( ) — 只发射最后的一项数据

Observable.just(1,2,3,4,5,6)        .last()        .subscribe(newAction1() {@Overridepublicvoidcall(Integer i){                Log.d("RxJava", String.valueOf(i));            }        });

结果：

11-06 03:49:46.710 6582-6582/? D/RxJava: 6

skip( ) — 跳过开始的N项数据

Observable.just(1,2,3,4,5,6)        .skip(3)        .subscribe(newAction1() {@Overridepublicvoidcall(Integer i){                Log.d("RxJava", String.valueOf(i));            }        });

结果：

11-06 03:49:46.710 6582-6582/? D/RxJava: 411-06 03:49:46.710 6582-6582/? D/RxJava: 511-06 03:49:46.710 6582-6582/? D/RxJava: 6

take( ) — 只发射开始的N项数据

Observable.just(1,2,3,4,5,6)        .take(3)        .subscribe(i -> {            Log.d("RxJava",String.valueOf(i));        });

结果：

11-06 03:49:46.710 6582-6582/? D/RxJava: 111-06 03:49:46.710 6582-6582/? D/RxJava: 211-06 03:49:46.710 6582-6582/? D/RxJava: 3

first( ) and takeFirst( ) — 只发射第一项数据，或者满足某种条件的第一项数据

Observable.just(1,2,3,4,5,6)        .first()        .subscribe(i -> {            Log.d("RxJava",String.valueOf(i));        });

结果：

11-06 03:49:46.710 6582-6582/? D/RxJava: 1

elementAt( ) — 发射第N项数据

Observable.just(1,2,3,4,5,6)        .elementAt(3)        .subscribe(i -> {            Log.d("RxJava",String.valueOf(i));        });

结果：

11-06 03:49:46.710 6582-6582/? D/RxJava: 4

sample( ) or throttleLast( ) — 定期发射Observable最近的数据

Observable.interval(1,TimeUnit.SECONDS)        .sample(4, TimeUnit.SECONDS)        .subscribe(i -> {            Log.d("RxJava",String.valueOf(i));        });

结果：interval()每隔一秒发送整数序列，sample()每隔4秒，获取Observable的数据，结果如下：

-16618/keye.com.rxjavaobserver D/RxJava: 3-16618/keye.com.rxjavaobserver D/RxJava: 6-16618/keye.com.rxjavaobserver D/RxJava: 10-16618/keye.com.rxjavaobserver D/RxJava: 14-16618/keye.com.rxjavaobserver D/RxJava: 18-16618/keye.com.rxjavaobserver D/RxJava: 22

debounce( ) — 只有当Observable在指定的时间后还没有发射数据时，才发射一个数据

Observable.create(newObservable.OnSubscribe() {@Overridepublicvoidcall(Subscriber subscriber){try{for(inti =1; i <10; i++) {                subscriber.onNext(i);                Thread.sleep(i *1000);//每次发送，延迟i*1秒}            subscriber.onCompleted();        }catch(Exception e) {            subscriber.onError(e);        }    }})        .subscribeOn(Schedulers.newThread())        .debounce(3000, TimeUnit.MILLISECONDS)//3秒没有数据，则发送.subscribe(newAction1() {@Overridepublicvoidcall(Integer integer){                Log.d("RxJava", String.valueOf(integer));            }        });

结果：前3个数延迟短，没有触发debounce()操作符，第4个数延迟3秒，debounce()生效

30534-30550/keye.com.rxjavaobserver D/RxJava: 430534-30550/keye.com.rxjavaobserver D/RxJava: 530534-30550/keye.com.rxjavaobserver D/RxJava: 630534-30550/keye.com.rxjavaobserver D/RxJava: 730534-30550/keye.com.rxjavaobserver D/RxJava: 8

distinct( ) — 过滤掉重复数据

Observable.just(1,2,1,4,1,6)        .distinct()        .subscribe(i -> {            Log.d("RxJava",String.valueOf(i));        });

结果：

11-06 04:38:49.987 19504-19504/keye.com.rxjavaobserver D/RxJava: 111-06 04:38:49.987 19504-19504/keye.com.rxjavaobserver D/RxJava: 211-06 04:38:49.987 19504-19504/keye.com.rxjavaobserver D/RxJava: 411-06 04:38:49.988 19504-19504/keye.com.rxjavaobserver D/RxJava: 6

ofType( ) — 只发射指定类型的数据

Observable.just(1,"2",3,"4",5,6)        .ofType(Integer.class)        .subscribe(i -> {            Log.d("RxJava", String.valueOf(i));        });

结果：

11-06 04:44:28.321 25785-25785/keye.com.rxjavaobserver D/RxJava: 1

11-06 04:44:28.321 25785-25785/keye.com.rxjavaobserver D/RxJava: 3

11-06 04:44:28.321 25785-25785/keye.com.rxjavaobserver D/RxJava: 5

11-06 04:44:28.321 25785-25785/keye.com.rxjavaobserver D/RxJava: 6