8b5493967f
The addition of a second round of filtering introduced a bug that would cause the system to log false filter and section changes for all notifs on every run of the pipeline. Previously, we had logic like the following: (assume that, in the previous run, entryA was filtered out by filter1 during the pre-finalized stage) 1. preGroupFilters run, nothing returns true. Set entryA.mExcludingFilter to null. It changed! Log it. 2. preFinalizeFilters run, filter1 returns true. Set entryA.mExcludingFilter to it. It changed! Log it. NotifSections had a similar bug that would null out their assigned section every time they were filtered out. To solve this, we introduce an mPreviousExcludingFilter field on NotificationEntry that will allow us to determine whether the filter actually changed as compared to the previous run. We also move that logging logic to the end of the pipeline. To solve the sectioning issue, we just don't null out sections when the entry is filtered out. Long-term, we should move to a system similar to the one above, but that's more complicated. Test: atest Bug: 112656837 Change-Id: Ib78dbbb0346947210cc1b6b49547595895e9fce5
SystemUI
“Everything you see in Android that's not an app”
SystemUI is a persistent process that provides UI for the system but outside of the system_server process.
The starting point for most of sysui code is a list of services that extend SystemUI that are started up by SystemUIApplication. These services then depend on some custom dependency injection provided by Dependency.
Inputs directed at sysui (as opposed to general listeners) generally come in through IStatusBar. Outputs from sysui are through a variety of private APIs to the android platform all over.
SystemUIApplication
When SystemUIApplication starts up, it will start up the services listed in config_systemUIServiceComponents or config_systemUIServiceComponentsPerUser.
Each of these services extend SystemUI. SystemUI provides them with a Context and gives them callbacks for onConfigurationChanged (this historically was the main path for onConfigurationChanged, now also happens through ConfigurationController). They also receive a callback for onBootCompleted since these objects may be started before the device has finished booting.
Each SystemUI service is expected to be a major part of system ui and the goal is to minimize communication between them. So in general they should be relatively silo'd.
Dependencies
The first SystemUI service that is started should always be Dependency. Dependency provides a static method for getting a hold of dependencies that have a lifecycle that spans sysui. Dependency has code for how to create all dependencies manually added. SystemUIFactory is also capable of adding/replacing these dependencies.
Dependencies are lazily initialized, so if a Dependency is never referenced at runtime, it will never be created.
If an instantiated dependency implements Dumpable it will be included in dumps of sysui (and bug reports), allowing it to include current state information. This is how *Controllers dump state to bug reports.
If an instantiated dependency implements ConfigurationChangeReceiver it will receive onConfigurationChange callbacks when the configuration changes.
IStatusBar
CommandQueue is the object that receives all of the incoming events from the system_server. It extends IStatusBar and dispatches those callbacks back any number of listeners. The system_server gets a hold of the IStatusBar when StatusBar calls IStatusBarService#registerStatusBar, so if StatusBar is not included in the XML service list, it will not be registered with the OS.
CommandQueue posts all incoming callbacks to a handler and then dispatches those messages to each callback that is currently registered. CommandQueue also tracks the current value of disable flags and will call #disable immediately for any callbacks added.
There are a few places where CommandQueue is used as a bus to communicate across sysui. Such as when StatusBar calls CommandQueue#recomputeDisableFlags. This is generally used a shortcut to directly trigger CommandQueue rather than calling StatusManager and waiting for the call to come back to IStatusBar.
Default SystemUI services list
com.android.systemui.Dependency
Provides custom dependency injection.
com.android.systemui.util.NotificationChannels
Creates/initializes the channels sysui uses when posting notifications.
com.android.systemui.keyguard.KeyguardViewMediator
Manages keyguard view state.
com.android.systemui.recents.Recents
Recents tracks all the data needed for recents and starts/stops the recents activity. It provides this cached data to RecentsActivity when it is started.
com.android.systemui.volume.VolumeUI
Registers all the callbacks/listeners required to show the Volume dialog when it should be shown.
com.android.systemui.stackdivider.Divider
Shows the drag handle for the divider between two apps when in split screen mode.
com.android.systemui.status.phone.StatusBar
This shows the UI for the status bar and the notification shade it contains. It also contains a significant amount of other UI that interacts with these surfaces (keyguard, AOD, etc.). StatusBar also contains a notification listener to receive notification callbacks.
com.android.systemui.usb.StorageNotification
Tracks USB status and sends notifications for it.
com.android.systemui.power.PowerUI
Tracks power status and sends notifications for low battery/power saver.
com.android.systemui.media.RingtonePlayer
Plays ringtones.
com.android.systemui.keyboard.KeyboardUI
Shows UI for keyboard shortcuts (triggered by keyboard shortcut).
com.android.systemui.pip.PipUI
Shows the overlay controls when Pip is showing.
com.android.systemui.shortcut.ShortcutKeyDispatcher
Dispatches shortcut to System UI components.
@string/config_systemUIVendorServiceComponent
Component allowing the vendor/OEM to inject a custom component.
com.android.systemui.util.leak.GarbageMonitor$Service
Tracks large objects in sysui to see if there are leaks.
com.android.systemui.LatencyTester
Class that only runs on debuggable builds that listens to broadcasts that simulate actions in the system that are used for testing the latency.
com.android.systemui.globalactions.GlobalActionsComponent
Shows the global actions dialog (long-press power).
com.android.systemui.ScreenDecorations
Draws decorations about the screen in software (e.g. rounded corners, cutouts).
com.android.systemui.biometrics.BiometricDialogImpl
Biometric UI.