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过滤操作

过滤操作

作者: 书魂X | 来源:发表于2018-04-07 13:44 被阅读0次

    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

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