Rxjava2-Android-Samlpes（一）

2018-11-30 本文已影响13人仕明同学

最近工作不那么忙，计划重新搭建一个MVP架构！基于Rxjava2-Rxandroid首先掌握RxJava2的使用的方式！
此文章是根据老外amitshekhariitbhu的RxJava2-Android-SamplesDemo 改装而成，是个翻译版本，足够应付对RxJava2的全部姿势！
GitHub地址： RxJava2-Android-Samples
- Map - >通过对每个项应用函数来变换Observable发出的项
- Zip - >通过指定的函数将多个Observable的排放组合在一起，并根据此函数的结果为每个组合发出单个项目
- Filter - >仅发出通过谓词测试的Observable中的那些项
- FlatMap - >将Observable发出的项目转换为Observables，然后将这些项目的排放量变为单个Observable
- Take - >仅发出Observable发出的前n项
- Reduce - >按顺序将一个函数应用于Observable发出的每个项目，并发出最终值
- Skip - >抑制Observable发出的前n项
- Buffer - >定期将Observable发出的项目收集到bundle中并发出这些bundle而不是一次发送一个项目
- Concat - >从两个或多个Observable发射发射而不交错
- Replay - >确保所有观察者看到相同的发射物品序列，即使他们在Observable开始发射物品后订阅
- Merge - >通过合并它们的排放将多个Observable组合成一个
- SwitchMap - >将Observable发出的项目变换为Observables，并镜像最近转换的Observable发出的项目

Operators

1、简单的一个顺序执行的Demo

 /*
     * 一个一个地发出两个值的简单例子
     */
    private void doSomeWork() {
        getObservable()
                // 在后台线程上运行
                .subscribeOn(Schedulers.io())
                // 在主线程上被通知
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(getObserver());
    }

    private Observable<String> getObservable() {
        return Observable.just("1", "2","3","4","5","6");
    }

d.dispose(); todo 如果这个方法放开的话，就不会往下面走了

 private Observer<String> getObserver() {
        return new Observer<String>() {
            /**
             *
             *为观察者提供取消（处理）的方法。
             *连接（通道）和可观察到的两个
             *同步（从{{Link Lang-OnNeXT（object）}）和异步方式。
             */
            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " onSubscribe : " + d.isDisposed());
                //处理资源，操作应该是幂等的。
                //d.dispose();  todo 如果这个方法放开的话，就不会往下面走了

            }

            @Override
            public void onNext(String value) {
                Log.d(TAG, " onNext : value : " + value);
            }

            @Override
            public void onError(Throwable e) {
                Log.d(TAG, " onError : " + e.getMessage());
            }

            @Override
            public void onComplete() {
                Log.d(TAG, " onComplete");
            }
        };
    }

输出结果

11-30 10:03:17.883 16586-16586/com.rxjava2.android.samples D/SimpleExampleActivity:  onSubscribe : false
11-30 10:03:17.923 16586-16586/com.rxjava2.android.samples D/SimpleExampleActivity:  onNext : value : 1
11-30 10:03:17.931 16586-16586/com.rxjava2.android.samples D/SimpleExampleActivity:  onNext : value : 2
11-30 10:03:17.938 16586-16586/com.rxjava2.android.samples D/SimpleExampleActivity:  onNext : value : 3
11-30 10:03:17.944 16586-16586/com.rxjava2.android.samples D/SimpleExampleActivity:  onNext : value : 4
11-30 10:03:17.950 16586-16586/com.rxjava2.android.samples D/SimpleExampleActivity:  onNext : value : 5
11-30 10:03:17.955 16586-16586/com.rxjava2.android.samples D/SimpleExampleActivity:  onNext : value : 6
11-30 10:03:17.961 16586-16586/com.rxjava2.android.samples D/SimpleExampleActivity:  onComplete

2、通过map运算符处理网咯请求的Demo,就比如说我去网络上请求个ApiUser回来，然后转化成我想要的User类

  private void doSomeWork() {
        getObservable()
                // Run on a background thread
                .subscribeOn(Schedulers.io())
                // Be notified on the main thread
                .observeOn(AndroidSchedulers.mainThread())
                .map(new Function<List<ApiUser>, List<User>>() {
                     //通过前面的东西，如何获取后面的东西
                    @Override
                    public List<User> apply(List<ApiUser> apiUsers) {
                        return Utils.convertApiUserListToUserList(apiUsers);
                    }
                })
                .subscribe(getObserver());
    }

    private Observable<List<ApiUser>> getObservable() {
        return Observable.create(new ObservableOnSubscribe<List<ApiUser>>() {
            @Override
            public void subscribe(ObservableEmitter<List<ApiUser>> e) {
                if (!e.isDisposed()) {
                    // List<ApiUser> 得到这个 对象
                    e.onNext(Utils.getApiUserList());
                    e.onComplete();
                }
            }
        });
    }

处理得到的List<User>


  //处理得到的 List<User>
    private Observer<List<User>> getObserver() {
        return new Observer<List<User>>() {

            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " onSubscribe : " + d.isDisposed());
            }

            @Override
            public void onNext(List<User> userList) {
                Log.d(TAG, " onNext : " + userList.size());
            }

            @Override
            public void onError(Throwable e) {
                Log.d(TAG, " onError : " + e.getMessage());
            }

            @Override
            public void onComplete() {
                Log.d(TAG, " onComplete");
            }
        };

输出结果

11-30 10:22:26.566 16586-16586/com.rxjava2.android.samples D/MapExampleActivity:  onSubscribe : false
11-30 10:22:26.619 16586-16586/com.rxjava2.android.samples D/MapExampleActivity:  onNext : 3
11-30 10:22:26.624 16586-16586/com.rxjava2.android.samples D/MapExampleActivity:  onComplete

3、两个复杂的操作放到子线程中去，然后在主线程中去处理两队球迷的问题 zip
获取数据源

  private Observable<List<User>> getCricketFansObservable() {
        return Observable.create(new ObservableOnSubscribe<List<User>>() {
            @Override
            public void subscribe(ObservableEmitter<List<User>> e) {
                if (!e.isDisposed()) {
                    e.onNext(Utils.getUserListWhoLovesCricket());
                    e.onComplete();
                }
            }
        });
    }

    private Observable<List<User>> getFootballFansObservable() {
        return Observable.create(new ObservableOnSubscribe<List<User>>() {
            @Override
            public void subscribe(ObservableEmitter<List<User>> e) {
                if (!e.isDisposed()) {
                    e.onNext(Utils.getUserListWhoLovesFootball());
                    e.onComplete();
                }
            }
        });
    }

处理

  private void doSomeWork() {
        // 获取喜欢足球名单的人员   获取板球球迷的名单
        Observable.zip(getCricketFansObservable(), getFootballFansObservable(),
                // 有点kotlin的啊 第一个对应的是沙面位置的第一个，最后是期望
                new BiFunction<List<User>, List<User>, List<User>>() {
                    @Override
                    public List<User> apply(List<User> cricketFans, List<User> footballFans) {
                        return Utils.filterUserWhoLovesBoth(cricketFans, footballFans);
                    }
                })
                // Run on a background thread
                .subscribeOn(Schedulers.io())
                // Be notified on the main thread
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(getObserver());
    }

结果监听

  private Observer<List<User>> getObserver() {
        return new Observer<List<User>>() {

            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " onSubscribe : " + d.isDisposed());
            }

            @Override
            public void onNext(List<User> userList) {
                textView.append(" onNext");
                textView.append(AppConstant.LINE_SEPARATOR);
                for (User user : userList) {
                    textView.append(" firstname : " + user.firstname);
                    textView.append(AppConstant.LINE_SEPARATOR);
                }
                Log.d(TAG, " onNext : " + userList.size());
            }

            @Override
            public void onError(Throwable e) {
                textView.append(" onError : " + e.getMessage());
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onError : " + e.getMessage());
            }

            @Override
            public void onComplete() {
                textView.append(" onComplete");
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onComplete");
            }
        };

输出，过程就是找出两个类的共性，然后放到主线程操作它的结果

11-30 10:28:16.326 16586-16586/com.rxjava2.android.samples D/ZipExampleActivity:  onSubscribe : false
11-30 10:28:16.353 16586-16586/com.rxjava2.android.samples D/ZipExampleActivity:  onNext : 1
11-30 10:28:16.358 16586-16586/com.rxjava2.android.samples D/ZipExampleActivity:  onComplete

4、对一些耗时操作的问题，可以使用使用容器 Disposable ,在活动被破坏后不要发送事件

    //一次性容器，可以容纳多个其他一次性物品，并提供O(1)添加和移除复杂性。
    private final CompositeDisposable disposables = new CompositeDisposable();
  @Override
    protected void onDestroy() {
        super.onDestroy();
        //在活动被破坏后不要发送事件
        disposables.clear(); // do not send event after activity has been destroyed
    }

 disposables.add(sampleObservable()
                // Run on a background thread
                .subscribeOn(Schedulers.io())
                // Be notified on the main thread
                .observeOn(AndroidSchedulers.mainThread())
                .subscribeWith(new DisposableObserver<String>() {
                    @Override
                    public void onComplete() {
                        textView.append(" onComplete");
                        textView.append(AppConstant.LINE_SEPARATOR);
                        Log.d(TAG, " onComplete");
                    }

                    @Override
                    public void onError(Throwable e) {
                        textView.append(" onError : " + e.getMessage());
                        textView.append(AppConstant.LINE_SEPARATOR);
                        Log.d(TAG, " onError : " + e.getMessage());
                    }

                    @Override
                    public void onNext(String value) {
                        textView.append(" onNext : value : " + value);
                        textView.append(AppConstant.LINE_SEPARATOR);
                        Log.d(TAG, " onNext value : " + value);
                    }
                }));

sampleObservable


 static Observable<String> sampleObservable() {
        return Observable.defer(new Callable<ObservableSource<? extends String>>() {
            @Override
            public ObservableSource<? extends String> call() {
                // Do some long running operation
                // 做一些长时间运行的操作
                SystemClock.sleep(2000);
                return Observable.just("one", "two", "three", "four", "five");
            }
        });
    }

输出结果

11-30 10:32:47.735 16586-16586/com.rxjava2.android.samples D/DisposableExampleActivity:  onNext value : one
11-30 10:32:47.748 16586-16586/com.rxjava2.android.samples D/DisposableExampleActivity:  onNext value : two
11-30 10:32:47.755 16586-16586/com.rxjava2.android.samples D/DisposableExampleActivity:  onNext value : three
11-30 10:32:47.762 16586-16586/com.rxjava2.android.samples D/DisposableExampleActivity:  onNext value : four
11-30 10:32:47.770 16586-16586/com.rxjava2.android.samples D/DisposableExampleActivity:  onNext value : five
11-30 10:32:47.775 16586-16586/com.rxjava2.android.samples D/DisposableExampleActivity:  onComplete

5、使用取算符，它只发出所需数量的值。这里只有5个中的3个

    private void doSomeWork() {
        getObservable()
                // Run on a background thread
                .subscribeOn(Schedulers.io())
                // Be notified on the main thread
                .observeOn(AndroidSchedulers.mainThread())
                .take(3)
                .subscribe(getObserver());
    }

    private Observable<Integer> getObservable() {
        return Observable.just(1, 2, 3, 4, 5);
    }

监听

 private Observer<Integer> getObserver() {
        return new Observer<Integer>() {

            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " onSubscribe : " + d.isDisposed());
            }

            @Override
            public void onNext(Integer value) {
                textView.append(" onNext : value : " + value);
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onNext value : " + value);
            }

            @Override
            public void onError(Throwable e) {
                textView.append(" onError : " + e.getMessage());
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onError : " + e.getMessage());
            }

            @Override
            public void onComplete() {
                textView.append(" onComplete");
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onComplete");
            }
        };
    }

输出结果

11-30 10:33:43.235 16586-16586/com.rxjava2.android.samples D/TakeExampleActivity:  onSubscribe : false
11-30 10:33:43.254 16586-16586/com.rxjava2.android.samples D/TakeExampleActivity:  onNext value : 1
11-30 10:33:43.259 16586-16586/com.rxjava2.android.samples D/TakeExampleActivity:  onNext value : 2
11-30 10:33:43.265 16586-16586/com.rxjava2.android.samples D/TakeExampleActivity:  onNext value : 3
11-30 10:33:43.271 16586-16586/com.rxjava2.android.samples D/TakeExampleActivity:  onComplete

6、延迟两秒运行

    private void doSomeWork() {
        getObservable()
                // Run on a background thread
                .subscribeOn(Schedulers.io())
                // Be notified on the main thread
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(getObserver());
    }

    private Observable<? extends Long> getObservable() {
        return Observable.timer(2, TimeUnit.SECONDS);
    }

7、定时器不断重复的运行使用RxJava运行使用间隔2秒的间隔运行任务的简单示例

 private final CompositeDisposable disposables = new CompositeDisposable();
 @Override
    protected void onDestroy() {
        super.onDestroy();
        disposables.clear(); // clearing it : do not emit after destroy
    }

使用间隔2秒的间隔运行任务的简单示例立即开始，initialDelay的开始的时间为0

   private void doSomeWork() {
        disposables.add(getObservable()
                // Run on a background thread
                .subscribeOn(Schedulers.io())
                // Be notified on the main thread
                .observeOn(AndroidSchedulers.mainThread())
                .subscribeWith(getObserver()));
    }

    private Observable<? extends Long> getObservable() {
        return Observable.interval(0, 2, TimeUnit.SECONDS);
    }

8、使用单观察者的简单例子

 /*
     * simple example using SingleObserver
     *使用单观察者的简单例子
     */
    private void doSomeWork() {
        Single.just("Amit")
                .subscribe(getSingleObserver());
    }

观察者

 private SingleObserver<String> getSingleObserver() {
        return new SingleObserver<String>() {
            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " onSubscribe : " + d.isDisposed());
            }

            @Override
            public void onSuccess(String value) {
                textView.append(" onNext : value : " + value);
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onNext value : " + value);
            }

            @Override
            public void onError(Throwable e) {
                textView.append(" onError : " + e.getMessage());
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onError : " + e.getMessage());
            }
        };
    }

输出结果：注意这里没有onNext的方法了，这个比较特殊

11-30 11:11:00.612 16586-16586/com.rxjava2.android.samples D/SingleObserverExampleActivity:  onSubscribe : true
11-30 11:11:00.615 16586-16586/com.rxjava2.android.samples D/SingleObserverExampleActivity:  onNext value : Amit

9、使用完全观测器的简单示例，延迟1s才去自行

  Completable completable = Completable.timer(1000, TimeUnit.MILLISECONDS);

        completable
                .subscribeOn(Schedulers.io())
                // Be notified on the main thread
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(getCompletableObserver());

 private CompletableObserver getCompletableObserver() {
        return new CompletableObserver() {
            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " onSubscribe : " + d.isDisposed());
            }

            @Override
            public void onComplete() {
                textView.append(" onComplete");
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onComplete");
            }

            @Override
            public void onError(Throwable e) {
                textView.append(" onError : " + e.getMessage());
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onError : " + e.getMessage());
            }
        };
    }

输出结果：延迟1s

11-30 11:12:41.248 16586-16586/com.rxjava2.android.samples D/CompletableObserverExampleActivity:  onSubscribe : false
11-30 11:12:42.270 16586-16586/com.rxjava2.android.samples D/CompletableObserverExampleActivity:  onComplete

10、使用流动性的简单示例，说白了就是累加的过程 1+2+3+4+5 ==== 使用Rxjava管理这个带了一个初始值

    Flowable<Integer> observable = Flowable.just(100, 2, 3, 4);

        observable.reduce(50+1, new BiFunction<Integer, Integer, Integer>() {
            @Override
            public Integer apply(Integer t1, Integer t2) {
                Log.d(TAG, "  t1 : " + t1);
                Log.d(TAG, "  t2 : " + t2);
                return t1 + t2;
            }
        }).subscribe(getObserver());

 private SingleObserver<Integer> getObserver() {

        return new SingleObserver<Integer>() {
            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " onSubscribe : " + d.isDisposed());
            }

            @Override
            public void onSuccess(Integer value) {
                textView.append(" onSuccess : value : " + value);
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onSuccess : value : " + value);
            }

            @Override
            public void onError(Throwable e) {
                textView.append(" onError : " + e.getMessage());
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onError : " + e.getMessage());
            }
        };
    }

输出结果：51+100+2+3+4=160

11-30 11:14:40.489 16586-16586/com.rxjava2.android.samples D/FlowableExampleActivity:  onSubscribe : false
11-30 11:14:40.490 16586-16586/com.rxjava2.android.samples D/FlowableExampleActivity:   t1 : 51
      t2 : 100
      t1 : 151
      t2 : 2
      t1 : 153
      t2 : 3
      t1 : 156
11-30 11:14:40.491 16586-16586/com.rxjava2.android.samples D/FlowableExampleActivity:   t2 : 4
11-30 11:14:40.496 16586-16586/com.rxjava2.android.samples D/FlowableExampleActivity:  onSuccess : value : 160

11、说白了就是累加的过程 1+2+3+4+5 ==== 使用Rxjava管理这个没有带一个初始值

  /*
     * simple example using reduce to add all the number
     *
     * 简单的例子，用以减少所有数字的添加
     */
    private void doSomeWork() {
        getObservable()
                .reduce(new BiFunction<Integer, Integer, Integer>() {
                    @Override
                    public Integer apply(Integer t1, Integer t2) {
                        return t1 + t2;
                    }
                })
                .subscribe(getObserver());
    }

    private Observable<Integer> getObservable() {
        return Observable.just(1, 2, 3, 4);
    }

    private MaybeObserver<Integer> getObserver() {
        return new MaybeObserver<Integer>() {
            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " onSubscribe : " + d.isDisposed());
            }

            @Override
            public void onSuccess(Integer value) {
                textView.append(" onSuccess : value : " + value);
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onSuccess : value : " + value);
            }

            @Override
            public void onError(Throwable e) {
                textView.append(" onError : " + e.getMessage());
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onError : " + e.getMessage());
            }

            @Override
            public void onComplete() {
                textView.append(" onComplete");
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onComplete");
            }
        };
    }

输出结果

11-30 11:16:17.035 16586-16586/com.rxjava2.android.samples D/ReduceExampleActivity:  onSubscribe : false
11-30 11:16:17.039 16586-16586/com.rxjava2.android.samples D/ReduceExampleActivity:  onSuccess : value : 10

12 、一个buffer 缓冲取，我要从缓冲区中取数据，而且是跳着取数据，就要这样做

   /*
     * simple example using buffer operator - bundles all emitted values into a list
     *
     * 使用缓冲运算符的简单示例-将所有发出的值捆绑到列表中
     */
    private void doSomeWork() {

        Observable<List<String>> buffered = getObservable().buffer(3, 1);

        // 3 means,  从开始索引和创建列表中最多需要三个
        // 1 means, 每次跳一步
        // so the it gives the following list
        // 1 - one, two, three
        // 2 - two, three, four
        // 3 - three, four, five
        // 4 - four, five
        // 5 - five

        buffered.subscribe(getObserver());
    }

    private Observable<String> getObservable() {
        return Observable.just("one", "two", "three", "four", "five");
    }

    private Observer<List<String>> getObserver() {
        return new Observer<List<String>>() {

            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " onSubscribe : " + d.isDisposed());
            }

            @Override
            public void onNext(List<String> stringList) {
                textView.append(" onNext size : " + stringList.size());
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onNext : size :" + stringList.size());
                for (String value : stringList) {
                    textView.append(" value : " + value);
                    textView.append(AppConstant.LINE_SEPARATOR);
                    Log.d(TAG, " : value :" + value);
                }

            }

            @Override
            public void onError(Throwable e) {
                textView.append(" onError : " + e.getMessage());
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onError : " + e.getMessage());
            }

            @Override
            public void onComplete() {
                textView.append(" onComplete");
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onComplete");
            }
        };
    }

输出结果：以此取出3个数字，同时角标移动1.把这个buffer中的值去完成就ok

11-30 11:17:25.002 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  onSubscribe : false
11-30 11:17:25.009 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  onNext : size :3
11-30 11:17:25.012 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  : value :one
11-30 11:17:25.014 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  : value :two
11-30 11:17:25.016 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  : value :three
11-30 11:17:25.018 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  onNext : size :3
11-30 11:17:25.019 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  : value :two
11-30 11:17:25.021 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  : value :three
11-30 11:17:25.022 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  : value :four
11-30 11:17:25.025 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  onNext : size :3
11-30 11:17:25.027 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  : value :three
11-30 11:17:25.029 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  : value :four
11-30 11:17:25.031 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  : value :five
11-30 11:17:25.033 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  onNext : size :2
11-30 11:17:25.035 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  : value :four
11-30 11:17:25.037 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  : value :five
11-30 11:17:25.039 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  onNext : size :1
11-30 11:17:25.040 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  : value :five
11-30 11:17:25.041 16586-16586/com.rxjava2.android.samples D/BufferExampleActivity:  onComplete

13、对数据中特定的信息做处理使用过滤器操作符只发出偶数值的简单示例

  /*
     * simple example by using filter operator to emit only even value
     * 使用过滤器操作符只发出偶数值的简单示例
     */
    private void doSomeWork() {
        Observable.just(1, 2, 3, 4, 5, 6)
                .filter(new Predicate<Integer>() {
                    @Override
                    public boolean test(Integer integer) {
                        return integer % 2 == 0;
                    }
                })
                .subscribe(getObserver());
    }


    private Observer<Integer> getObserver() {
        return new Observer<Integer>() {

            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " onSubscribe : " + d.isDisposed());
            }

            @Override
            public void onNext(Integer value) {
                textView.append(" onNext : ");
                textView.append(AppConstant.LINE_SEPARATOR);
                textView.append(" value : " + value);
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onNext ");
                Log.d(TAG, " value : " + value);
            }

            @Override
            public void onError(Throwable e) {
                textView.append(" onError : " + e.getMessage());
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onError : " + e.getMessage());
            }

            @Override
            public void onComplete() {
                textView.append(" onComplete");
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onComplete");
            }
        };
    }

输出结果，简单的意思就是取偶数

11-30 11:20:24.775 16586-16586/com.rxjava2.android.samples D/FilterExampleActivity:  onSubscribe : false
11-30 11:20:24.779 16586-16586/com.rxjava2.android.samples D/FilterExampleActivity:  onNext 
11-30 11:20:24.780 16586-16586/com.rxjava2.android.samples D/FilterExampleActivity:  value : 2
11-30 11:20:24.782 16586-16586/com.rxjava2.android.samples D/FilterExampleActivity:  onNext 
     value : 4
11-30 11:20:24.786 16586-16586/com.rxjava2.android.samples D/FilterExampleActivity:  onNext 
     value : 6
11-30 11:20:24.788 16586-16586/com.rxjava2.android.samples D/FilterExampleActivity:  onComplete

14、使用跳过操作符，它不会发出前2个值。对前面两个值不会操作

 /* Using skip operator, it will not emit
    * the first 2 values.
    * 使用跳过操作符，它不会发出前2个值。
    */
    private void doSomeWork() {
        getObservable()
                // Run on a background thread
                .subscribeOn(Schedulers.io())
                // Be notified on the main thread
                .observeOn(AndroidSchedulers.mainThread())
                .skip(2)
                .subscribe(getObserver());
    }

    private Observable<Integer> getObservable() {
        return Observable.just(1, 2, 3, 4, 5);
    }

    private Observer<Integer> getObserver() {
        return new Observer<Integer>() {

            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " onSubscribe : " + d.isDisposed());
            }

            @Override
            public void onNext(Integer value) {
                textView.append(" onNext : value : " + value);
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onNext value : " + value);
            }

            @Override
            public void onError(Throwable e) {
                textView.append(" onError : " + e.getMessage());
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onError : " + e.getMessage());
            }

            @Override
            public void onComplete() {
                textView.append(" onComplete");
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onComplete");
            }
        };
    }

输出结果：跳出前面的两个值

11-30 11:21:22.224 16586-16586/com.rxjava2.android.samples D/SkipExampleActivity:  onSubscribe : false
11-30 11:21:22.235 16586-16586/com.rxjava2.android.samples D/SkipExampleActivity:  onNext value : 3
11-30 11:21:22.236 16586-16586/com.rxjava2.android.samples D/SkipExampleActivity:  onNext value : 4
     onNext value : 5
11-30 11:21:22.237 16586-16586/com.rxjava2.android.samples D/SkipExampleActivity:  onComplete

15、使用扫描算子，它也发送先前的结果。意思就是我关心每次运算的结果，是每次运算的结果这个有个关键的地方 subscribe 里面的观察者 onNext的方法是先行执行的

  /* Using scan operator, it sends also the previous result
    * 使用扫描算子，它也发送先前的结果。
    * */
    private void doSomeWork() {
        getObservable()
                // Run on a background thread
                .subscribeOn(Schedulers.io())
                // Be notified on the main thread
                .observeOn(AndroidSchedulers.mainThread())
                .scan(new BiFunction<Integer, Integer, Integer>() {
                    @Override
                    public Integer apply(Integer int1, Integer int2) {
                        Log.d(TAG, "  int1 : " + int1);
                        Log.d(TAG, "  int2 : " + int2);
                        return int1 + int2;
                    }
                })
                .subscribe(getObserver());
    }

    private Observable<Integer> getObservable() {
        return Observable.just(1, 2, 3, 4, 5);
    }

    private Observer<Integer> getObserver() {
        return new Observer<Integer>() {

            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " onSubscribe : " + d.isDisposed());
            }

            @Override
            public void onNext(Integer value) {
                textView.append(" onNext : value : " + value);
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onNext value : " + value);
            }

            @Override
            public void onError(Throwable e) {
                textView.append(" onError : " + e.getMessage());
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onError : " + e.getMessage());
            }

            @Override
            public void onComplete() {
                textView.append(" onComplete");
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onComplete");
            }
        };
    }

输出结果：三角形数

11-30 11:22:24.396 16586-16586/com.rxjava2.android.samples D/ScanExampleActivity:  onSubscribe : false
11-30 11:22:24.409 16586-16586/com.rxjava2.android.samples D/ScanExampleActivity:  onNext value : 1
      int1 : 1
      int2 : 2
11-30 11:22:24.411 16586-16586/com.rxjava2.android.samples D/ScanExampleActivity:  onNext value : 3
      int1 : 3
      int2 : 3
11-30 11:22:24.414 16586-16586/com.rxjava2.android.samples D/ScanExampleActivity:  onNext value : 6
      int1 : 6
      int2 : 4
11-30 11:22:24.417 16586-16586/com.rxjava2.android.samples D/ScanExampleActivity:  onNext value : 10
      int1 : 10
      int2 : 5
11-30 11:22:24.419 16586-16586/com.rxjava2.android.samples D/ScanExampleActivity:  onNext value : 15
11-30 11:22:24.420 16586-16586/com.rxjava2.android.samples D/ScanExampleActivity:  onComplete

16、PublishSubject 我个人理解的话，就是一堆数据我要发送给别人，但是呢最后几个数字我又要发送给其他人，所以就需要使用到这个，使用重放操作符，重放确保所有观察者看到相同的序列。发射项目，即使它们订阅后，可观测已经开始发射项目。我个人理解的是，发送一个buffer，给第一个观察者，同时我要把这个buffer的尾部长度为4的在发送给第二个观察者。

 private void doSomeWork() {
        PublishSubject<Integer> source = PublishSubject.create();
        ConnectableObservable<Integer> connectableObservable = source.replay(4); 
         //连接可连接的可观察的
        connectableObservable.connect();
        connectableObservable.subscribe(getFirstObserver());
        source.onNext(1);
        source.onNext(2);
        source.onNext(3);
        source.onNext(4);
        source.onNext(5);
        source.onNext(6);
        source.onNext(7);
        source.onComplete();
        connectableObservable.subscribe(getSecondObserver());
    }


    private Observer<Integer> getFirstObserver() {
        return new Observer<Integer>() {

            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " First onSubscribe : " + d.isDisposed());
            }

            @Override
            public void onNext(Integer value) {
                textView.append(" First onNext : value : " + value);
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " First onNext value : " + value);
            }

            @Override
            public void onError(Throwable e) {
                textView.append(" First onError : " + e.getMessage());
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " First onError : " + e.getMessage());
            }

            @Override
            public void onComplete() {
                textView.append(" First onComplete");
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " First onComplete");
            }
        };
    }

    private Observer<Integer> getSecondObserver() {
        return new Observer<Integer>() {

            @Override
            public void onSubscribe(Disposable d) {
                textView.append(" Second onSubscribe : isDisposed :" + d.isDisposed());
                Log.d(TAG, " Second onSubscribe : " + d.isDisposed());
                textView.append(AppConstant.LINE_SEPARATOR);
            }

            @Override
            public void onNext(Integer value) {
                textView.append(" Second onNext : value : " + value);
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " Second onNext value : " + value);
            }

            @Override
            public void onError(Throwable e) {
                textView.append(" Second onError : " + e.getMessage());
                Log.d(TAG, " Second onError : " + e.getMessage());
            }

            @Override
            public void onComplete() {
                textView.append(" Second onComplete");
                Log.d(TAG, " Second onComplete");
            }
        };
    }

输出结果

11-30 11:39:02.882 19690-19690/com.rxjava2.android.samples D/ReplayExampleActivity:  First onSubscribe : false
11-30 11:39:02.903 19690-19690/com.rxjava2.android.samples D/ReplayExampleActivity:  First onNext value : 1
11-30 11:39:02.911 19690-19690/com.rxjava2.android.samples D/ReplayExampleActivity:  First onNext value : 2
11-30 11:39:02.919 19690-19690/com.rxjava2.android.samples D/ReplayExampleActivity:  First onNext value : 3
11-30 11:39:02.926 19690-19690/com.rxjava2.android.samples D/ReplayExampleActivity:  First onNext value : 4
11-30 11:39:02.932 19690-19690/com.rxjava2.android.samples D/ReplayExampleActivity:  First onNext value : 5
11-30 11:39:02.938 19690-19690/com.rxjava2.android.samples D/ReplayExampleActivity:  First onNext value : 6
11-30 11:39:02.944 19690-19690/com.rxjava2.android.samples D/ReplayExampleActivity:  First onNext value : 7
11-30 11:39:02.950 19690-19690/com.rxjava2.android.samples D/ReplayExampleActivity:  First onComplete
11-30 11:39:02.954 19690-19690/com.rxjava2.android.samples D/ReplayExampleActivity:  Second onSubscribe : false
11-30 11:39:02.963 19690-19690/com.rxjava2.android.samples D/ReplayExampleActivity:  Second onNext value : 4
11-30 11:39:02.968 19690-19690/com.rxjava2.android.samples D/ReplayExampleActivity:  Second onNext value : 5
11-30 11:39:02.972 19690-19690/com.rxjava2.android.samples D/ReplayExampleActivity:  Second onNext value : 6
11-30 11:39:02.977 19690-19690/com.rxjava2.android.samples D/ReplayExampleActivity:  Second onNext value : 7
11-30 11:39:02.979 19690-19690/com.rxjava2.android.samples D/ReplayExampleActivity:  Second onComplete

17 、依次的发送两个数组，而且里面两个数组的是有序的输出的，所以就要使用到这个里面的

 /**
     * 使用CONTAT运算符组合可观察性：CONTAT维护
     * 可观察的顺序。
     * 将按顺序发射所有7个值
     * 这里第一个“A1”，“A2”，“A3”，“A4”，然后是“B1”，“B2”，“B3”。
     * 首先从第一个观察到然后
     * 所有从第二可观察到的所有顺序
     */
    private void doSomeWork() {
        final String[] aStrings = {"A1", "A2", "A3", "A4"};
        final String[] bStrings = {"B1", "B2", "B3"};

        final Observable<String> aObservable = Observable.fromArray(aStrings);
        final Observable<String> bObservable = Observable.fromArray(bStrings);

        Observable.concat(aObservable, bObservable)
                .subscribe(getObserver());
    }


    private Observer<String> getObserver() {
        return new Observer<String>() {

            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " onSubscribe : " + d.isDisposed());
            }

            @Override
            public void onNext(String value) {
                textView.append(" onNext : value : " + value);
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onNext : value : " + value);
            }

            @Override
            public void onError(Throwable e) {
                textView.append(" onError : " + e.getMessage());
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onError : " + e.getMessage());
            }

            @Override
            public void onComplete() {
                textView.append(" onComplete");
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onComplete");
            }
        };
    }

输出结果

11-30 11:42:43.359 19690-19690/com.rxjava2.android.samples D/ConcatExampleActivity:  onSubscribe : false
11-30 11:42:43.369 19690-19690/com.rxjava2.android.samples D/ConcatExampleActivity:  onNext : value : A1
11-30 11:42:43.375 19690-19690/com.rxjava2.android.samples D/ConcatExampleActivity:  onNext : value : A2
11-30 11:42:43.382 19690-19690/com.rxjava2.android.samples D/ConcatExampleActivity:  onNext : value : A3
11-30 11:42:43.388 19690-19690/com.rxjava2.android.samples D/ConcatExampleActivity:  onNext : value : A4
11-30 11:42:43.393 19690-19690/com.rxjava2.android.samples D/ConcatExampleActivity:  onNext : value : B1
11-30 11:42:43.399 19690-19690/com.rxjava2.android.samples D/ConcatExampleActivity:  onNext : value : B2
11-30 11:42:43.404 19690-19690/com.rxjava2.android.samples D/ConcatExampleActivity:  onNext : value : B3
11-30 11:42:43.409 19690-19690/com.rxjava2.android.samples D/ConcatExampleActivity:  onComplete

18、依次的发送两个数组，而且里面两个数组的不是有序的输出的，但是我始终没有测出来结果，哎哎难受的很日了狗！ RxJava 合并组合两个（或多个）Observable数据源

  private void doSomeWork() {
        final String[] aStrings = {"A1", "A2", "A3", "A4","1", "2", "3", "4","5", "6", "7", "8","9", "10", "11", "12",};
        final String[] bStrings = {"B1", "B2", "B3","B1", "B2", "B3","B1", "B2", "B3","B1", "B2", "B3","B1", "B2", "B3","B1", "B2", "B3","B1", "B2", "B3"};

        final Observable<String> aObservable = Observable.fromArray(aStrings);
        final Observable<String> bObservable = Observable.fromArray(bStrings);

        Observable.merge(aObservable, bObservable)
                .subscribe(getObserver());
    }


    private Observer<String> getObserver() {
        return new Observer<String>() {

            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " onSubscribe : " + d.isDisposed());
            }

            @Override
            public void onNext(String value) {
                textView.append(" onNext : value : " + value);
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onNext : value : " + value);
            }

            @Override
            public void onError(Throwable e) {
                textView.append(" onError : " + e.getMessage());
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onError : " + e.getMessage());
            }

            @Override
            public void onComplete() {
                textView.append(" onComplete");
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onComplete");
            }
        };
    }

输出结果：合并多个Observables的发射物， Merge 可能会让合并的Observables发射的数据交错（有一个类似的操作符 Concat 不会让数据交错，它会按顺序一个接着一个发射多个Observables的发射物，虽然我的结果没有测试出来，但是呢？真的有可能数据会交叉！！！！

11-30 11:46:44.466 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onSubscribe : false
11-30 11:46:44.477 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : A1
11-30 11:46:44.484 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : A2
11-30 11:46:44.490 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : A3
11-30 11:46:44.495 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : A4
11-30 11:46:44.499 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : 1
11-30 11:46:44.503 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : 2
11-30 11:46:44.508 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : 3
11-30 11:46:44.512 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : 4
11-30 11:46:44.515 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : 5
11-30 11:46:44.517 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : 6
11-30 11:46:44.519 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : 7
11-30 11:46:44.522 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : 8
11-30 11:46:44.525 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : 9
11-30 11:46:44.528 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : 10
11-30 11:46:44.532 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : 11
11-30 11:46:44.535 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : 12
11-30 11:46:44.537 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B1
11-30 11:46:44.539 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B2
11-30 11:46:44.540 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B3
11-30 11:46:44.542 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B1
11-30 11:46:44.543 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B2
11-30 11:46:44.546 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B3
11-30 11:46:44.548 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B1
11-30 11:46:44.551 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B2
11-30 11:46:44.553 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B3
11-30 11:46:44.556 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B1
11-30 11:46:44.559 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B2
11-30 11:46:44.561 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B3
11-30 11:46:44.564 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B1
11-30 11:46:44.567 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B2
11-30 11:46:44.570 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B3
11-30 11:46:44.573 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B1
11-30 11:46:44.575 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B2
11-30 11:46:44.577 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B3
11-30 11:46:44.578 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B1
11-30 11:46:44.580 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B2
11-30 11:46:44.581 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onNext : value : B3
11-30 11:46:44.582 19690-19690/com.rxjava2.android.samples D/MergeExampleActivity:  onComplete

19、让属性跟着数据bean传递下去
Car 类

public class Car {

    private String brand;

    public void setBrand(String brand) {
        this.brand = brand;
    }

    public Observable<String> brandDeferObservable() {
        return Observable.defer(new Callable<ObservableSource<? extends String>>() {
            @Override
            public ObservableSource<? extends String> call() {
                return Observable.just(brand);
            }
        });
    }
}

  /*
     * Defer used for Deferring Observable code until subscription in RxJava
     * 推迟在RxJava订阅可观察代码直到订阅
     */
    private void doSomeWork() {

        Car car = new Car();

        Observable<String> brandDeferObservable = car.brandDeferObservable();
        // 即使我们在创建了可观察的品牌之后设置了品牌，我们也会得到宝马的品牌。如果我们不使用延迟器，我们将没有作为品牌。
        car.setBrand("BMW");  // Even if we are setting the brand after creating Observable
        // we will get the brand as BMW.
        // If we had not used defer, we would have got null as the brand.

        brandDeferObservable
                .subscribe(getObserver());
    }

    private Observer<String> getObserver() {
        return new Observer<String>() {

            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " onSubscribe : " + d.isDisposed());
            }

            @Override
            public void onNext(String value) {
                textView.append(" onNext : value : " + value);
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onNext : value : " + value);
            }

            @Override
            public void onError(Throwable e) {
                textView.append(" onError : " + e.getMessage());
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onError : " + e.getMessage());
            }

            @Override
            public void onComplete() {
                textView.append(" onComplete");
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onComplete");
            }
        };
    }

输出结果

11-30 14:17:07.380 19690-19690/com.rxjava2.android.samples D/DeferExampleActivity:  onSubscribe : false
11-30 14:17:07.388 19690-19690/com.rxjava2.android.samples D/DeferExampleActivity:  onNext : value : BMW
11-30 14:17:07.392 19690-19690/com.rxjava2.android.samples D/DeferExampleActivity:  onComplete

20、去重，对数据源，进行去重的操作

 /*
     * distinct() suppresses duplicate items emitted by the source Observable.
     * 区别（）抑制由可观察到的源发出的重复项。
     */
    private void doSomeWork() {

        getObservable()
                .distinct()
                .subscribe(getObserver());
    }

    private Observable<Integer> getObservable() {
        return Observable.just(1, 2, 1, 1, 2, 3, 4, 6, 4);
    }


    private Observer<Integer> getObserver() {
        return new Observer<Integer>() {

            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " onSubscribe : " + d.isDisposed());
            }

            @Override
            public void onNext(Integer value) {
                textView.append(" onNext : value : " + value);
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onNext value : " + value);
            }

            @Override
            public void onError(Throwable e) {
                Log.d(TAG, " onError : " + e.getMessage());
            }

            @Override
            public void onComplete() {
                Log.d(TAG, " onComplete");
            }
        };
    }

输出的结果

11-30 14:20:04.382 19690-19690/com.rxjava2.android.samples D/DistinctExampleActivity:  onSubscribe : false
11-30 14:20:04.388 19690-19690/com.rxjava2.android.samples D/DistinctExampleActivity:  onNext value : 1
11-30 14:20:04.391 19690-19690/com.rxjava2.android.samples D/DistinctExampleActivity:  onNext value : 2
11-30 14:20:04.394 19690-19690/com.rxjava2.android.samples D/DistinctExampleActivity:  onNext value : 3
11-30 14:20:04.397 19690-19690/com.rxjava2.android.samples D/DistinctExampleActivity:  onNext value : 4
11-30 14:20:04.400 19690-19690/com.rxjava2.android.samples D/DistinctExampleActivity:  onNext value : 6
     onComplete

21、对数据源传递，但是只不过是取最后一个数，把前面的都不需要了，同时给了一个默认的值 A1

private void doSomeWork() {
        // the default item ("A1") to emit if the source ObservableSource is empty
        getObservable().last("A1") // the default item ("A1") to emit if the source ObservableSource is empty
                .subscribe(getObserver());
    }

    private Observable<String> getObservable() {
        return Observable.just("A1", "A2", "A3", "A4", "A5", "A6");
    }

    private SingleObserver<String> getObserver() {
        return new SingleObserver<String>() {

            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, " onSubscribe : " + d.isDisposed());
            }

            @Override
            public void onSuccess(String value) {
                textView.append(" onNext : value : " + value);
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onNext value : " + value);
            }


            @Override
            public void onError(Throwable e) {
                textView.append(" onError : " + e.getMessage());
                textView.append(AppConstant.LINE_SEPARATOR);
                Log.d(TAG, " onError : " + e.getMessage());
            }
        };
    }

输出结果

11-30 14:20:42.788 19690-19690/com.rxjava2.android.samples D/DistinctExampleActivity:  onSubscribe : false
11-30 14:20:42.800 19690-19690/com.rxjava2.android.samples D/DistinctExampleActivity:  onNext value : A6

未完待续。。。。。Rxjava2-Android-Samlpes（二）

Rxjava2-Android-Samlpes（一）

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