Reactive Everything: Replacing Callbacks

So far, all the examples that we’ve looked at emit either one value, meaning that it can be modeled as a Single, or it can tell us if an operation succeeded or failed, meaning that it can be modeled as a Completable.

How might we convert areas in our app that receive continuous updates or events—for example, location updates, view click events, sensor events, and so on?

We’ll look at two ways to do this, first by using .create(), and then by using a new construct called Subject.