1、创建被观察者Observable

    Observable ob= Observable.create(new Observable.OnSubscribe<String>() {

        @Override
        public void call(Subscriber<? super String> subscriber) {
            //subscriber主要用来发射数据
            subscriber.onNext("sss");
            subscriber.onCompleted();
        }
    });

2、创建观察者

    Observer<String> observer=new Observer<String>() {
        @Override
        public void onCompleted() {
            Log.d(TAG, "onCompleted ");
        }

        @Override
        public void onError(Throwable e) {

        }

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

3、被观察者订阅观察者

  ob.map(new Func1<String,String>() {
                @Override
                public String call(String o) {
                    return o+"nihao";
                }
            }).subscribe(observer);
}

• Fun1接口
  /**
  * Represents a function with one argument.
  * @param <T> the first argument type
  * @param <R> the result type 返回参数类型
  */
  public interface Func1<T, R> extends Function {
  R call(T t);
  }