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Rxjava 操作符-4-组合操作符

Rxjava 操作符-4-组合操作符

作者: 揭穿套路 | 来源:发表于2019-01-03 11:56 被阅读0次

    1、startWith

    map 操作符的作用是对 对象进行转换

    Observable.range(0, 5).filter(new Predicate<Integer>() {
        @Override
        public boolean test(Integer integer) throws Exception {
            return integer > 2;//自定义的条件,只有符合条件的结果才会提交给观察者
        }
    }).subscribe(consumer);
    
    12-29 12:00:37.769 461-461/com.rxjavademo E/tag: 3
    12-29 12:00:37.774 461-461/com.rxjavademo E/tag: 4
    

    2、merge

    merge 合并请求,但是不能保证顺序

    Observable<Integer> firstObservable = Observable.just(0, 1, 2).subscribeOn(Schedulers.io());
    Observable<Integer> secondObservable = Observable.just(3, 4, 5);
    Observable.merge(firstObservable, secondObservable).subscribe(consumer, onErrorAction);
    
    12-29 13:28:12.280 6062-6062/com.rxjavademo E/tag: 3
    12-29 13:28:12.285 6062-6062/com.rxjavademo E/tag: 4
    12-29 13:28:12.290 6062-6062/com.rxjavademo E/tag: 5
    12-29 13:28:12.297 6062-6062/com.rxjavademo E/tag: 0
    12-29 13:28:12.303 6062-6062/com.rxjavademo E/tag: 1
    12-29 13:28:12.307 6062-6062/com.rxjavademo E/tag: 2
    

    merge 只要有一个请求出错了就会中断 其他请求,
    mergeDelayError 延迟错误,请求都走完 再报错

    3、concat

    merge 合并请求,严格按照顺序执行

    Observable<Integer> firstObservable = Observable.just(0, 1, 2).subscribeOn(Schedulers.io());
    Observable<Integer> secondObservable = Observable.just(3, 4, 5);
    Observable.concat(firstObservable, secondObservable).subscribe(consumer, onErrorAction);
    
    12-29 13:32:13.606 6062-6062/com.rxjavademo E/tag: 0
    12-29 13:32:13.612 6062-6062/com.rxjavademo E/tag: 1
    12-29 13:32:13.615 6062-6062/com.rxjavademo E/tag: 2
    12-29 13:32:13.621 6062-6062/com.rxjavademo E/tag: 3
    12-29 13:32:13.624 6062-6062/com.rxjavademo E/tag: 4
    12-29 13:32:13.627 6062-6062/com.rxjavademo E/tag: 5
    

    concat 只要有一个请求出错了就会中断 其他请求,
    concatArrayDelayError 延迟错误,请求都走完 再报错

      Observable.concat(
                            Observable.create(new ObservableOnSubscribe<Integer>() {
                                @Override
                                public void subscribe(ObservableEmitter<Integer> emitter) throws Exception {
    
                                    emitter.onNext(1);
                                    emitter.onNext(2);
                                    emitter.onNext(3);
                                    emitter.onError(new NullPointerException()); // 发送Error事件,因为无使用concatDelayError,所以第2个Observable将不会发送事件
                                    emitter.onComplete();
                                }
                            }),
                            Observable.just(4, 5, 6))
                            .subscribe(new Observer<Integer>() {
                                @Override
                                public void onSubscribe(Disposable d) {
    
                                }
                                @Override
                                public void onNext(Integer value) {
                                    Log.e("tag", "onNext"+ value  );
                                }
    
                                @Override
                                public void onError(Throwable e) {
                                    Log.e("tag"," onError");
                                }
    
                                @Override
                                public void onComplete() {
                                    Log.e("tag","onComplete");
                                }
                            });
    
    12-29 13:45:04.863 13255-13255/com.rxjavademo E/tag: onNext1
    12-29 13:45:04.866 13255-13255/com.rxjavademo E/tag: onNext2
    12-29 13:45:04.863 13255-13255/com.rxjavademo E/tag: onNext3
    12-29 13:45:04.866 13255-13255/com.rxjavademo E/tag: onError
    

    4、zip

    zip操作符,会将多个Observable对象转换成一个Observable对象然后进行发送,zip 跟merge的区别是 zip 等待多个请求全部成功以后再一起通知

    //
              Observable<Integer> integerObservable = Observable.range(0, 4);
                    Observable<String> stringObservable = Observable.just("a", "b", "c", "d");
                    Observable.zip(integerObservable, stringObservable, new BiFunction<Integer, String, Object>() {
                        @Override
                        public Object apply(Integer integer, String s) throws Exception {
                            return "数字为:" + integer + "……字符为:" + s;
                        }
                    }).subscribe(consumer);
    12-29 13:47:43.590 13255-13255/com.rxjavademo E/tag: 数字为:0……字符为:a
    12-29 13:47:43.595 13255-13255/com.rxjavademo E/tag: 数字为:1……字符为:b
    12-29 13:47:43.601 13255-13255/com.rxjavademo E/tag: 数字为:2……字符为:c
    12-29 13:47:43.607 13255-13255/com.rxjavademo E/tag: 数字为:3……字符为:d
    

    5、combineLatest

    不同于zip操作符的是,combineLatest会将 其中一个Observable发射数据后 取其最后一项,组合所有未发送的Observable

    integerObservable = Observable.just(1, 2, 3);
    stringObservable = Observable.just("a", "b", "c");
    Observable.combineLatest(integerObservable, stringObservable, new BiFunction<Integer, String, Object>() {
        @Override
        public Object apply(Integer num, String info) {
            //在这里的转换关系为将数字与字串内容进行拼接
            return "数字为:" + num + "……字符为:" + info;
        }
    }).subscribe(consumer);
    
    12-29 13:55:57.154 13255-13255/com.rxjavademo E/tag: 数字为:3……字符为:a
    12-29 13:55:57.163 13255-13255/com.rxjavademo E/tag: 数字为:3……字符为:b
    12-29 13:55:57.169 13255-13255/com.rxjavademo E/tag: 数字为:3……字符为:c
    
    integerObservable = Observable.just(1, 2, 3).delay(200, TimeUnit.MILLISECONDS, AndroidSchedulers.mainThread());
    stringObservable = Observable.just("a", "b", "c");
    Observable.combineLatest(integerObservable, stringObservable, new BiFunction<Integer, String, Object>() {
                        @Override
                        public Object apply(Integer num, String info) {
                            //在这里的转换关系为将数字与字串内容进行拼接
                            return "数字为:" + num + "……字符为:" + info;
                        }
                    }).subscribe(consumer);
    12-29 14:23:26.859 15193-15193/com.rxjavademo E/tag: 数字为:1……字符为:c
    12-29 14:23:26.869 15193-15193/com.rxjavademo E/tag: 数字为:2……字符为:c
    12-29 14:23:26.875 15193-15193/com.rxjavademo E/tag: 数字为:3……字符为:c
    

    6、ignoreElements

    ignoreElements操作符忽略所有源Observable产生的结果,只会执行onCpmpleted()或者onError()方法

    Observable.range(0, 5).ignoreElements().subscribe(new Action() {
        @Override
        public void run() throws Exception {
            Log.e("tag","onCompleted()" );
        }
    }, consumer);
    
    12-29 12:39:59.976 3700-3700/com.rxjavademo E/tag: onCompleted()
    
    

    7、throttleFirst

    throttleFirst操作符,会定期发送这个时间段里源Observable发送的第一个数据

    Observable
            .create(new ObservableOnSubscribe<Object>() {
                @Override
                public void subscribe(ObservableEmitter<Object> emitter) throws Exception {
                    for (int i = 0; i < 10; i++) {
                        emitter.onNext(i);
                        //线程休眠100毫秒
                        try {
                            Thread.sleep(100);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                }
            })
            .throttleFirst(200, TimeUnit.MILLISECONDS)
            .subscribeOn(Schedulers.newThread())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(consumer);
    
    12-29 13:55:57.154 13255-13255/com.rxjavademo E/tag: 数字为:3……字符为:a
    12-29 13:55:57.163 13255-13255/com.rxjavademo E/tag: 数字为:3……字符为:b
    12-29 13:55:57.169 13255-13255/com.rxjavademo E/tag: 数字为:3……字符为:c
    

    6、throttleWithTimeout

    如果两次数据的发射间隔小于指定时间,就会丢弃前一次的数据,直到指定时间内都没有新数据发射时才进行发射

    Observable
            .create(new ObservableOnSubscribe<Object>() {
                @Override
                public void subscribe(ObservableEmitter<Object> emitter) throws Exception {
                    emitter.onNext(1);
                    try {
                        Thread.sleep(500);
                    } catch (InterruptedException e) {
                        throw Exceptions.propagate(e);
                    }
                    emitter.onNext(2);
                    try {
                        Thread.sleep(500);
                    } catch (InterruptedException e) {
                        throw Exceptions.propagate(e);
                    }
    
                    emitter.onNext(3);
                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        throw Exceptions.propagate(e);
                    }
                    emitter.onNext(4);
                    emitter.onNext(5);
                    emitter.onNext(6);
                    emitter.onComplete();
                }
            })
            .throttleWithTimeout(800, TimeUnit.MILLISECONDS)
            .subscribeOn(Schedulers.newThread())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(consumer);
    
    12-29 13:10:12.382 4834-4834/com.rxjavademo E/tag: 3
    12-29 13:10:12.582 4834-4834/com.rxjavademo E/tag: 6
    

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