How do their APIs compare?

Here's a comparison of the two libraries' public APIs, based on what's in the retrieved source and documentation:

reactivex/rxandroid

RxAndroid's API is small and focused on bridging RxJava 3 with Android's threading model:

• AndroidSchedulers — provides a Scheduler that runs work on the main thread or on any given Looper (mentioned in the README's "Observing on the main thread" section, and exercised in tests at [rxandroid/src/test/java/io/reactivex/rxjava3/android/schedulers/AndroidSchedulersTest.java:L1-L45]).
• RxAndroidPlugins — a plugin/hook system "to inject handlers to certain standard RxAndroid operations" [rxandroid/src/main/java/io/reactivex/rxjava3/android/plugins/RxAndroidPlugins.java:L14-L23], letting consumers override scheduler creation (e.g., for testing, via Function<Scheduler, Scheduler> handlers as seen in the test imports at [rxandroid/src/test/java/io/reactivex/rxjava3/android/plugins/RxAndroidPluginsTest.java:L14-L30]).
• MainThreadDisposable — an abstract Disposable base class that guarantees its dispose action executes on the main thread, with a static verifyMainThread() helper for validating the calling thread when building custom Observables that touch UI APIs [rxandroid/src/main/java/io/reactivex/rxjava3/android/MainThreadDisposable.java:L20-L45].

So RxAndroid's surface is essentially: one Scheduler entry point, one plugin/config class, and one Disposable utility class — it doesn't provide UI widgets; it's a threading/reactive-streams adapter layer.

umano/androidslidinguppanel

This library's API is a custom Android ViewGroup and its supporting drag mechanics, meant to be used directly in XML layouts:

• SlidingUpPanelLayout — the main custom view, used as the root element of an activity layout with exactly two children (main content + sliding panel) [README.md:L36-L80]. It's configured largely through XML attributes like umanoPanelHeight, umanoShadowHeight, and umanoDragView, plus programmatic setters such as setDragView(...), setFadeOnClickListener(...), and setPanelState(PanelState...) as shown in the demo activity [demo/src/main/java/com/sothree/slidinguppanel/demo/DemoActivity.java:L86-L99].
• PanelSlideListener — a listener interface with callbacks onPanelSlide(View panel, float slideOffset) and onPanelStateChanged(View panel, PanelState previousState, PanelState newState) for observing panel drag/state transitions [demo/src/main/java/com/sothree/slidinguppanel/demo/DemoActivity.java:L86-L96].
• PanelState — an enum representing panel states (e.g., COLLAPSED) used in setPanelState and the listener callback.
• ViewDragHelper — an internal utility class (adapted from AOSP) for implementing drag-based interaction in custom ViewGroups [library/src/main/java/com/sothree/slidinguppanel/ViewDragHelper.java:L17-L38]. It's a support class rather than something typical consumers instantiate directly.

Key contrast

Aspect	rxandroid	androidslidinguppanel
API shape	Schedulers, plugin hooks, Disposable base class	Custom ViewGroup widget + listener interface + enum + drag helper
Consumption style	Programmatic (.observeOn(AndroidSchedulers.mainThread()))	Declarative XML + programmatic listeners/setters
Domain	Threading/reactive-stream integration for RxJava 3	UI/layout component for draggable sliding panels
Extensibility	RxAndroidPlugins for swapping scheduler behavior (e.g., in tests)	PanelSlideListener for observing UI state; ViewDragHelper for building custom drag-based views

In short, RxAndroid exposes a minimal, non-visual API purely for thread scheduling within Rx chains, while androidslidin