Android-RxJava源码分析

最简单的源码分析

//创建一个上游 Observable：
Observable observable = Observable.create(new ObservableOnSubscribe() {
    @Override
    public void subscribe(ObservableEmitter emitter) throws Exception {
        emitter.onNext(1);
        emitter.onNext(2);
        emitter.onNext(3);
        emitter.onComplete();
    }
});
//创建一个下游 Observer
Observer observer = new Observer() {
    @Override
    public void onSubscribe(Disposable d) {
        Log.d(TAG, "subscribe");
    }
​
    @Override
    public void onNext(Integer value) {
        Log.d(TAG, "" + value);
    }
​
    @Override
    public     void onError(Throwable e) {
        Log.d(TAG, "error");
    }
​
    @Override
    public void onComplete() {
        Log.d(TAG, "complete");
    }
};
//建立连接
observable.subscribe(observer);

事件流

UML类图

函数调用流程图

Map操作符源码分析

        //上游操作1
        Observable observable = Observable.create(new ObservableOnSubscribe() {
            @Override
            public void subscribe(ObservableEmitter emitter) throws Exception {
                emitter.onNext(1);
                emitter.onNext(2);
                emitter.onNext(3);
            }
        });
        //上游操作2
        Observable mapObservable = observable.map(new Function() {
            @Override
            public String apply(Integer integer) throws Exception {
                return "This is result " + integer;
            }
        });
        //下游操作
        Observer observer = new Observer() {
            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, "subscribe");
            }
​
            @Override
            public void onNext(String value) {
                Log.d(TAG, "" + value);
            }
​
            @Override
            public void onError(Throwable e) {
                Log.d(TAG, "error");
            }
​
            @Override
            public void onComplete() {
                Log.d(TAG, "complete");
            }
        };
        //订阅
        mapObservable.subscribe(observer);

事件流

UML类图

函数调用流程图

线程切换源码分析

//上游操作
        Observable observable = Observable.create(new ObservableOnSubscribe() {
            @Override
            public void subscribe(ObservableEmitter emitter) throws Exception {
                Log.d(TAG, "Observable thread is : " + Thread.currentThread().getName());
                Log.d(TAG, "emit 1");
                emitter.onNext(1);
            }
        });
        //下游操作
        Observer observer = new Observer() {
            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, "subscribe");
            }
​
            @Override
            public void onNext(Integer value) {
                Log.d(TAG, "Observer thread is : " + Thread.currentThread().getName());
                Log.d(TAG, "" + value);
            }
​
            @Override
            public void onError(Throwable e) {
                Log.d(TAG, "error");
            }
​
            @Override
            public void onComplete() {
                Log.d(TAG, "complete");
            }
        };
        //订阅操作
        observable
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(observer);

subscribeOn的UML类图

observeOn的UML类图

事件流及函数调用流程图

事件流和函数调用流程与Map操作符类似，通过责任链模式，将切换线程操作包装成一个管道，然后在管道中进行Observer和Observable的线程切换操作。