Rxjava学习笔记（一）

最新推荐文章于 2024-10-12 08:53:50 发布

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最新推荐文章于 2024-10-12 08:53:50 发布

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分类专栏： android 文章标签： listview

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本文介绍了RxJava的基本用法，包括创建Observable对象并订阅Observer对象的过程。详细解释了ObservableEmitter的作用及如何通过Disposable来切断上下游之间的通信。

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Rxjava学习

基本用法


            Observable<Integer> observable = Observable.create(new ObservableOnSubscribe<Integer>() {
            @Override
            public void subscribe(ObservableEmitter<Integer> e) throws Exception {
                e.onNext(1);
                e.onNext(2);
                e.onNext(3);
                e.onComplete();
            }
        });
           Observer<Integer> observer = new Observer<Integer>() {
            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG,"onSubscribe");
            }
            @Override
            public void onNext(Integer value) {
                Log.d(TAG,""+value);
            }
            @Override
            public void onError(Throwable e) {
                Log.d(TAG,"onError");
            }

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

        observable.subscribe(observer);


//运行结果
03-13 13:59:33.957 4183-4183/com.example.uds.recyclerviewtest D/MAP: onSubscribe
03-13 13:59:33.958 4183-4183/com.example.uds.recyclerviewtest D/MAP: 1
03-13 13:59:33.958 4183-4183/com.example.uds.recyclerviewtest D/MAP: 2
03-13 13:59:33.958 4183-4183/com.example.uds.recyclerviewtest D/MAP: 3
03-13 13:59:33.958 4183-4183/com.example.uds.recyclerviewtest D/MAP: onComplete

使用链式调用


Observable.create(new ObservableOnSubscribe<Integer>{
    @Override
    public void subscribe(ObservableEmitter<Integer> e) throws Exception {
          e.onNext(1);
          e.onNext(2);
          e.onNext(3);
          e.onComplete();
   }
}).subscrib(new Observer<Integer>() {
            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG,"onSubscribe");
            }
            @Override
            public void onNext(Integer value) {
                Log.d(TAG,""+value);
            }
            @Override
            public void onError(Throwable e) {
                Log.d(TAG,"onError");
            }

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

比较关键的两个对象：ObservableEmitter 和 Disposable

ObservableEmitter 的意思是发射器的意思，就是用来发送事件的

onNext(T value) 可以发送多次
onComplete() 发送一次后可以接着发送 onNext 但是不再被接收到
onError(Throwable error) 只可以发送一次，可以接着发送 onNext 但是不再被接受到

Disposable 的意思是一次性，用完即丢的意思，调用dispose() 方法会切断上游和下游之间的通信

虽然是切断但是上游依然可以继续发送剩余的事件，下游不再接收而已


Observable.create(new ObservableOnSubscribe<Integer>() {
            @Override
            public void subscribe(ObservableEmitter<Integer> e) throws Exception {
                Log.d(TAG,"emit 1");
                e.onNext(1);
                Log.d(TAG,"emit 2");
                e.onNext(2);
                Log.d(TAG,"emit 3");
                e.onNext(3);
                e.onComplete();
            }
        }).subscribe(new Observer<Integer>() {
            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG,"onSubscribe");
                mDisposable = d;
            }
            @Override
            public void onNext(Integer value) {
                Log.d(TAG,"onNext "+value);
                if(value == 2){
                    Log.d(TAG,"disposable");
                    mDisposable.dispose();
                    Log.d(TAG,"isDisposed:" + mDisposable.isDisposed());
                }
            }
            @Override
            public void onError(Throwable e) {
                Log.d(TAG,"onError");
            }

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


//结果

03-13 14:46:02.647 13356-13356/com.example.uds.recyclerviewtest D/MAP: onSubscribe
03-13 14:46:02.647 13356-13356/com.example.uds.recyclerviewtest D/MAP: emit 1
03-13 14:46:02.647 13356-13356/com.example.uds.recyclerviewtest D/MAP: onNext 1
03-13 14:46:02.647 13356-13356/com.example.uds.recyclerviewtest D/MAP: emit 2
03-13 14:46:02.647 13356-13356/com.example.uds.recyclerviewtest D/MAP: onNext 2
03-13 14:46:02.647 13356-13356/com.example.uds.recyclerviewtest D/MAP: disposable
03-13 14:46:02.647 13356-13356/com.example.uds.recyclerviewtest D/MAP: isDisposedtrue
03-13 14:46:02.647 13356-13356/com.example.uds.recyclerviewtest D/MAP: emit 3

subscribe() 的重载方法介绍


    public final Disposable subscribe() {}
    public final Disposable subscribe(Consumer<? super T> onNext) {}
    public final Disposable subscribe(Consumer<? super T> onNext, Consumer<? super Throwable> onError) {} 
    public final Disposable subscribe(Consumer<? super T> onNext, Consumer<? super Throwable> onError, Action onComplete) {}
    public final Disposable subscribe(Consumer<? super T> onNext, Consumer<? super Throwable> onError, Action onComplete, Consumer<? super Disposable> onSubscribe) {}
    public final void subscribe(Observer<? super T> observer) {}

Consumer 只关心onNext事件


        Observable.create(new ObservableOnSubscribe<Integer>() {
            @Override
            public void subscribe(ObservableEmitter<Integer> emitter) throws Exception {
                Log.d(TAG, "emit 1");
                emitter.onNext(1);
                Log.d(TAG, "emit 2");
                emitter.onNext(2);
                Log.d(TAG, "emit 3");
                emitter.onNext(3);
                Log.d(TAG, "emit complete");
                emitter.onComplete();
                Log.d(TAG, "emit 4");
                emitter.onNext(4);
            }
        }).subscribe(new Consumer<Integer>() {
            @Override
            public void accept(Integer integer) throws Exception {
                Log.d(TAG, "onNext: " + integer);
            }
        });