CODEWITHSUNDEEP
javaevent-handlingrx-java
mtyson
mtyson

Reputation: 8550

RxJava: Watch custom class

I have a custom class, call it Builder. It has a method act(), that performs an async operation. When the operation is done, I want to emit an event.

How can I accomplish this in RxJava?

Seems like a straightforward task, but I have yet to see the right RxJava way to do it.

For more detail, a typical act() method looks like so:

    class Builder
       public void act() {
            processRunner.runAsync(new ProcessRunner.ProcessResultHandler(){
                @Override
                public void onComplete(int result) {
                    // Emit event
                }
            });
        }

And what I want is in the consuming class, to call:

builder.act()

And somehow be alerted to when onComplete() is called.

I also control ProcessRunner, so I'd like to convert that to RxJava and chain results, but for now I'll take the simple usecase!

Upvotes: 0

Views: 56

Answers (2)

Bhavdip Sagar
Bhavdip Sagar

Reputation: 1971

That can possible using PublishSubject in RxJava. Let me explain to you how you can use it into your builder. Create the class as shown below:

public class Communicator {
  private static Communicator  mCommunicator = new Communicator();
  private PublishSubject<Void> mGrabEvent = new PublishSubjetct.create();
  private Communicator(){
  }
  public static getCommunicator(){
   return mCommunicator
  }
  public static emitEventItem(){
     // you can pass any object that you want to listen
     mGrabEvent.onNext(null);
  }
 public PublishSubject<Void> subscribeEvent(){
   return mGrabEvent;
 }
}

This class would help you to emit & subscribe it for listening to that particular event anywhere into your application. Below I try to show you how to emit and hook that listener into you activity or fragment.

A. For emit the message from your builder class

class Builder{
  public void act() {
    processRunner.runAsync(new ProcessRunner.ProcessResultHandler(){
      @Override
      public void onComplete(int result) {
        // Emit event
        Communicatort.getCommunicator().emitEventItem();
      }
    });
  }
  }

B. Another end point where you would listen to it by subscribing it.

Communicatort.getCommunicator().subscribeEvent().subscribe(new Action<Void>(){
  @overrider
  public void call(Void void){
  }
});

C. In last, Make sure you should unsubscribe it onDestroy of the activity.

I hope that could help you. Let me know if you could understand in any point.

Thanks, Bhavdip

Upvotes: 1

Bharath Mg
Bharath Mg

Reputation: 1127

You need to return an Observable<Boolean> from your act method. Then you can call onCompleted on Subscriber which will be your consuming class.

Code:

 class Builder {
   public Observable<Boolean> act() {
      return Observable<Boolean>.create {
        public void call(final Subscriber subscriber) {
         processRunner.runAsync(new ProcessRunner.ProcessResultHandler(){
            @Override
            public void onComplete(int result) {
                subscriber.onNext(true);
                subscriber.onCompleted();
            }
        });
       }
      }
   }
 }

Consuming Class: 

     builder.act().subscribe({
        void onNext(boolean status) {}
        void onCompleted() { // finished }
      })

Code Not tested. There might be syntax errors.

Upvotes: 1

Related Questions