fix: podcast player panel draws under system navigation bar in main feed view

[mvanhorn]

Summary

The collapsed podcast playback panel no longer draws underneath the system navigation bar when playback starts from the main feed view. The bottom system-bar inset is now handled in the shared podcast panel code, so both host activities behave identically under edge-to-edge.

Why this matters

In #1647, @yukijoou narrowed the repro to playback started from the main feed without opening an article, which is why it did not reproduce at first: activity_news_detail.xml sets fitsSystemWindows on its root CoordinatorLayout, but activity_newsreader.xml only sets it on an inner CoordinatorLayout that does not contain the PodcastSlidingUpPanelLayout, leaving the panel flush with the physical screen bottom.

Changes

• An OnApplyWindowInsetsListener on the sliding panel raises the collapsed panel height by the system-bars bottom inset and pads the collapsed header so controls are not clipped.
• NewsDetailActivity already consumes the inset via fitsSystemWindows, so the listener receives a zero bottom inset there and behavior is unchanged. The root of activity_newsreader.xml intentionally keeps its existing edge-to-edge inset handling.

Testing

Static review against both layout variants (portrait and sw600dp-land); the inset math only adds the reported bottom inset on top of the existing 68dp panel height. A device pass on API 35 edge-to-edge is the remaining verification, which CI/screenshots from the reporter's repro path will exercise.

Fixes #1647

Signed-off-by: Matt Van Horn 455140+mvanhorn@users.noreply.github.com

[David-Development]

@mvanhorn Thanks for the contribution 🎉

I gave it a spin on amy Pixel 9 Pro (Android 16). The bottom inset is fixed now — the collapsed mini-player and the expanded player's bottom controls sit above the navigation bar correctly. 👍

But the top is still broken: when the panel is expanded, the player header/title is drawn under the status bar — which is part of what #1647 reported. The change only applies systemBars.bottom; there's no top inset. In activity_newsreader.xml the panel isn't inset at the top at all, unlike activity_news_detail.xml whose root CoordinatorLayout has fitsSystemWindows="true" (+ a top margin), so its expanded player clears the status bar.

Could you also handle the top inset for the expanded state? One thing to watch: the top inset should only apply when expanded — padding the root top unconditionally will push the header down and clip it in the collapsed mini-player. The existing onPanelSlideListener (with its slide offset) is probably the cleanest hook for that.

Context for the bigger picture: since the SDK 35 edge-to-edge switch we lean on fitsSystemWindows across most activities as a workaround, and the podcast panel in the feed is the spot that isn't covered. Longer term I'd like to drop fitsSystemWindows and handle insets consistently across activities — but that's out of scope here; handling the top inset when expanded should be enough to close this.