You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
95 lines
5.7 KiB
95 lines
5.7 KiB
7 months ago
|
# SysUI Media Controls Pipeline
|
||
|
|
|
||
|
|
[TOC]
|
||
|
|
|
||
|
|
## Purpose
|
||
|
|
|
||
|
|
Describe how events flow through the media controls pipeline, and provide a high level overview of what the different components do.
|
||
|
|
|
||
|
|
## Pipeline Diagram
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
* Orange: External inputs
|
||
|
|
* Blue: Internal listeners; all except `MediaDataManager` and `ResumeMediaBrowser` implement [`MediaDataManager.Listener`](/packages/SystemUI/src/com/android/systemui/media/MediaDataManager.kt#711) and receive `onMediaDataLoaded` and `onMediaDataRemoved` events
|
||
|
|
|
||
|
|
## Classes
|
||
|
|
|
||
|
|
Files under [`systemui/media/`](/packages/SystemUI/src/com/android/systemui/media/):
|
||
|
|
|
||
|
|
* UI
|
||
|
|
* `dialog/`
|
||
|
|
* Output switcher dialog (maintained by Settings team)
|
||
|
|
* IlluminationDrawable.kt
|
||
|
|
* LightSourceDrawable.kt
|
||
|
|
* These create the glow animation when you tap on a button (see [`qs_media_light_source`](/packages/SystemUI/res/drawable/qs_media_light_source.xml)). Should be reusable in other layouts.
|
||
|
|
* Carousel:
|
||
|
|
* MediaCarouselController.kt
|
||
|
|
* Keeps the carousel view up to date and handles state changes (e.g. expansion)
|
||
|
|
* Handles settings gear and page indicator
|
||
|
|
* MediaCarouselScrollHandler.kt
|
||
|
|
* Handles scrolling between players in the carousel
|
||
|
|
* MediaScrollView.kt
|
||
|
|
* Scrollview used in the carousel layout, has some custom measurement code
|
||
|
|
* Individual players:
|
||
|
|
* KeyguardMediaController.kt
|
||
|
|
* Lockscreen media controls have a special wrapper in order to work with the existing lockscreen notification layout
|
||
|
|
* MediaControlPanel.java
|
||
|
|
* Main class for media control UI
|
||
|
|
* SeekBarObserver.kt
|
||
|
|
* Updates seekbar state
|
||
|
|
* SeekBarViewModel.kt
|
||
|
|
* Implements its own `computePosition()` for the seekbar (to avoid continually polling the `PlaybackState`, which involves binder calls)
|
||
|
|
* Does some touch falsing (ignore flings, require drags to start near the thumb - otherwise users would often accidentally trigger the seekbar when they meant to move the carousel or shade)
|
||
|
|
* PlayerViewHolder.kt
|
||
|
|
* Holds references to the UI elements in the panel
|
||
|
|
* Animation support:
|
||
|
|
* MediaHierarchyManager.kt
|
||
|
|
* Responsible for placement of media view and animation between hosts
|
||
|
|
* MediaHost.kt
|
||
|
|
* Every location that a media player could be located needs a `MediaHost`
|
||
|
|
* Tracks configuration (if it should show inactive media, needs falsing, etc.)
|
||
|
|
* MediaHostStatesManager.kt
|
||
|
|
* Manages the various media host states and coordinates heights between different players
|
||
|
|
* Has the most up to date state for any location
|
||
|
|
* MediaViewController.kt
|
||
|
|
* Controls a single instance of a media player, keeps the media view states up to date
|
||
|
|
* Backend
|
||
|
|
* MediaData.kt
|
||
|
|
* Holds all the media data (track info, active/resume state, etc.)
|
||
|
|
* MediaDataCombineLatest.kt
|
||
|
|
* Combines update events from `MediaDataManager` and `MediaDeviceManager`, so that downstream listeners will have device info
|
||
|
|
* MediaDataFilter.kt
|
||
|
|
* Filters media data based on the current user
|
||
|
|
* Exit point for the pipeline: "external listeners" (currently `MediaHost` and `MediaCarouselController`), while they should be added via `MediaDataManager.addListener()`, will actually be listening to this output
|
||
|
|
* MediaDataManager.kt
|
||
|
|
* Entry point for the pipeline; initializes listener connections and assigns external listeners to the correct exit point
|
||
|
|
* Converts media notifications and resumable media info into `MediaData`
|
||
|
|
* MediaDeviceManager.kt
|
||
|
|
* Handles device updates
|
||
|
|
* MediaFeatureFlag.kt
|
||
|
|
* Utility to check whether media controls are enabled
|
||
|
|
* MediaSessionBasedFilter.kt
|
||
|
|
* Filters media events based on media session. This prevents duplicate controls in situations like casting where we might get both a local and remote object for the same media session.
|
||
|
|
* MediaTimeoutListener.kt
|
||
|
|
* Listens to `PlaybackState` and marks controls inactive after the media has been paused/stopped for 10 minutes (value can be adjusted locally with `adb shell setprop debug.sysui.media_timeout [ms]`)
|
||
|
|
* MediaResumeListener.kt
|
||
|
|
* Listens for new media data and attempts to find a valid `MediaBrowserService` for the app. If successful, sends the information back to the `MediaDataManager`
|
||
|
|
* Saves up to 5 valid `MediaBrowserService` components found this way, and queries them for recent media on boot or user change
|
||
|
|
* Note: the user can disable this feature completely (or block certain apps from being resumable) in [Settings](https://source.corp.google.com/android/packages/apps/Settings/src/com/android/settings/sound/ResumableMediaAppsController.java), in which case this listener will do nothing (or ignore updates from the blocked apps).
|
||
|
|
* ResumeMediaBrowser.java
|
||
|
|
* Connects to an app's [`MediaBrowser`](https://developer.android.com/reference/android/media/browse/MediaBrowser) to determine whether SystemUI is able to connect and find a recent [`MediaItem`](https://developer.android.com/reference/android/media/browse/MediaBrowser.MediaItem)
|
||
|
|
* Factory classes (for unit testing):
|
||
|
|
* LocalMediaManagerFactory.kt
|
||
|
|
* MediaBrowserFactory.java
|
||
|
|
* MediaControllerFactory.java
|
||
|
|
* ResumeMediaBrowserFactory.java
|
||
|
|
|
||
|
|
## Miscellaneous
|
||
|
|
|
||
|
|
Other useful documents:
|
||
|
|
|
||
|
|
* [go/sysui-media-resumption-requirements](https://goto.google.com/sysui-media-resumption-requirements) - Internal documentation for app developers about how to work with media resumption
|
||
|
|
* [Playing nicely with media controls](https://android-developers.googleblog.com/2020/08/playing-nicely-with-media-controls.html) - blog post on the Android 11 updates
|
||
|
|
* [Media Controls developer guide](https://developer.android.com/guide/topics/media/media-controls)
|