AndroidScheduler.java

[prabirshrestha]

Initial spike for AndroidScheduler.java.

Been using this for quite some time. But I don't like the concept using calling observer.observeOn(AndroidScheduler.getInstance()) as it sort of puts Android specific stuffs. Should RxJava support some concept of Schedulers.mainScheduler()? We can then set the default main schedulers using Schedulers.setMainScheduler(AndroidScheduler.getInstance()) when app starts.

[cloudbees-pull-request-builder]

RxJava-pull-requests #195 FAILURE
Looks like there's a problem with this pull request

[benjchristensen]

Thanks @prabirshrestha for the submission. Support for Android is something several people will be happy about getting.

Since I don't work with Android I'd like to pull @mustafasezgin into this conversation as he's using RxJava on Android at SoundCloud. Mustafa, can you review, contribute and/or answer questions?

Mustafa gave a presentation that hinted at the use of Schedulers for Android: http://backstage.soundcloud.com/2013/08/responsive-android-applications-with-sane-code/

I don't like the idea of global settings like Schedulers.setMainScheduler, as libraries would be stepping on each other.

I think something such as the following is a good approach, similar to the Schedulers factory class in Rx core:

AndroidScheduler.MAIN_SCHEDULER
... or ...
AndroidScheduler.mainScheduler()

[prabirshrestha]

AndroidScheduler.mainScheduler() definitely sounds better then AndroidScheduler.getInstance().

I named the method as getInstance so that the AndroidScheduler is similar to the SwingScheduler which uses getInstance().

I would also need help on writing the gradle build scripts.(Android SDK should also be installed in the CI server)

[benjchristensen]

Android dependencies should be in a repo such as Maven Central so that someone does not need to configure their environment correctly to build.

Is this what it needs?

http://search.maven.org/#artifactdetails%7Ccom.android.tools%7Csdk-common%7C22.1.3%7Cjar

The gradle file will be similar to this: https://github.com/Netflix/RxJava/blob/master/rxjava-contrib/rxjava-swing/build.gradle

... but you will add this dependency:

compile 'com.android.tools:sdk-common:22.1.3'

Also add your module to this file: https://github.com/Netflix/RxJava/blob/master/settings.gradle

For example, place this on the 2nd to last line before rxjava-swing:

'rxjava-contrib:rxjava-android', \

[muzzah]

@benjchristensen happy to help out, @mttkay (from the SoundCloud Android team) will also be valuable to the discussion.

We use the first method outlined by @benjchristensen to set a the main thread scheduler on an observable. The main thread scheduler is similar to the one submitted by @prabirshrestha with the second method being implemented using the Handler.postDelayed() method. For consistency with the core package I think the static method approach for the scheduler is more suited in this instance.

@mttkay wrote some helpful components related to fragments which we were also looking to opensource. Maybe we should look to getting that out sooner. @mttkay thoughts?

Also you should only need to add the main android sdk dependency http://search.maven.org/#search%7Cgav%7C1%7Cg%3A%22com.google.android%22%20AND%20a%3A%22android%22 using the provided maven scope.

[benjchristensen]

Thanks @mustafasezgin for getting involved. Nice to know you and @mttkay work together.

Yes, we only need the SDK as a provided not compile dependency. So like this in the build.gradle file:

provided 'com.google.android:android:4.1.1.4'

[jmhofer]

Why return null? Is this work in progress? - Maybe throw a NotSupportedException while this is not implemented?

[jmhofer]

Awesome. I was playing around with Android and RxJava already, too. But I guess for me, it'll be a libgdx integration mostly.

[mttkay]

Hey guys, indeed we have been using a more complete scheduler for a while, one that has an implementation for delayed messages too.

My suggestion is to rename AndroidScheduler to AndroidSchedulers (plural) since there may be more schedulers to be implemented for Android down the road (like scheduling via AsyncTasks). So we should have:

AndroidSchedulers.mainThread()

I'm also missing tests and build integration with this PR. It seems like it's a WIP, maybe we should combine our efforts around this?

[mttkay]

Have a look at the above PR. I've pulled the scheduler component out of our production app code and into rxjava-contrib.

The build should pass, the Scala adaptor seems to be causing trouble though? Seems to neither build on the public CI nor on my local machine. Test execution time is slightly up due to the addition of Robolectric, which goes through a start-up procedure to initialize a fake Android application environment for testing.

[prabirshrestha]

closing in favor of #318