SystemUI是一个系统级apk，位于frameworks\base\packages\SystemUI\ 主要功能有：
状态栏信息显示，比如电池，wifi信号，3G/4G等icon显示
通知面板，比如系统消息，第三方应用消息
近期任务栏显示面板，比如长按近期任务快捷键，显示近期使用的应用
截图服务
壁纸服务
SystemUI的启动流程
SystemServer启动后，会在Main Thread启动ActivityManagerService，当ActivityManagerService systemReady后，会去启动SystemUIService。
private void startOtherServices(@NonNull TimingsTraceAndSlog t) { mActivityManagerService.systemReady(() -> { Slog.i(TAG, "Making services ready"); t.traceBegin("StartActivityManagerReadyPhase"); mSystemServiceManager.startBootPhase(t, SystemService.PHASE_ACTIVITY_MANAGER_READY); t.traceEnd(); t.traceBegin("StartObservingNativeCrashes"); try { mActivityManagerService.startObservingNativeCrashes(); } catch (Throwable e) { reportWtf("observing native crashes", e); } t.traceEnd(); // No dependency on Webview preparation in system server. But this should // be completed before allowing 3rd party final String WEBVIEW_PREPARATION = "WebViewFactoryPreparation"; Future<?> webviewPrep = null; if (!mOnlyCore && mWebViewUpdateService != null) { webviewPrep = SystemServerInitThreadPool.submit(() -> { Slog.i(TAG, WEBVIEW_PREPARATION); TimingsTraceAndSlog traceLog = TimingsTraceAndSlog.newAsyncLog(); traceLog.traceBegin(WEBVIEW_PREPARATION); ConcurrentUtils.waitForFutureNoInterrupt(mZygotePreload, "Zygote preload"); mZygotePreload = null; mWebViewUpdateService.prepareWebViewInSystemServer(); traceLog.traceEnd(); }, WEBVIEW_PREPARATION); } if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_AUTOMOTIVE)) { t.traceBegin("StartCarServiceHelperService"); mSystemServiceManager.startService(CAR_SERVICE_HELPER_SERVICE_CLASS); t.traceEnd(); } t.traceBegin("StartSystemUI"); try { startSystemUi(context, windowManagerF); } catch (Throwable e) { reportWtf("starting System UI", e); } }
private static void startSystemUi(Context context, WindowManagerService windowManager) { PackageManagerInternal pm = LocalServices.getService(PackageManagerInternal.class); Intent intent = new Intent(); intent.setComponent(pm.getSystemUiServiceComponent()); intent.addFlags(Intent.FLAG_DEBUG_TRIAGED_MISSING); //Slog.d(TAG, "Starting service: " + intent); context.startServiceAsUser(intent, UserHandle.SYSTEM); windowManager.onSystemUiStarted(); }
frameworks\base\services\core\java\android\content\pm\PackageManagerInternal.java
/** * @return The SystemUI service component name. */ public abstract ComponentName getSystemUiServiceComponent();
抽象方法，具体实现在 PackageManagerService
mContext 是系统的
frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java实现
@Override public ComponentName getSystemUiServiceComponent() { return ComponentName.unflattenFromString(mContext.getResources().getString( com.android.internal.R.string.config_systemUIServiceComponent)); }
frameworks\base\core\res\res\values\config.xml
<!-- SystemUi service component --> <string name="config_systemUIServiceComponent" translatable="false" >com.android.systemui/com.android.systemui.SystemUIService</string>
启动SystemUIService
frameworks\base\packages\SystemUI\src\com\android\systemui\SystemUIService.java
调用startServicesIfNeeded启动一系列服务
public void onCreate() { super.onCreate(); // Start all of SystemUI ((SystemUIApplication) getApplication()).startServicesIfNeeded(); // Finish initializing dump logic mLogBufferFreezer.attach(mBroadcastDispatcher); // For debugging RescueParty if (Build.IS_DEBUGGABLE && SystemProperties.getBoolean("debug.crash_sysui", false)) { throw new RuntimeException(); } if (Build.IS_DEBUGGABLE) { // b/71353150 - looking for leaked binder proxies BinderInternal.nSetBinderProxyCountEnabled(true); BinderInternal.nSetBinderProxyCountWatermarks(1000,900); BinderInternal.setBinderProxyCountCallback( new BinderInternal.BinderProxyLimitListener() { @Override public void onLimitReached(int uid) { Slog.w(SystemUIApplication.TAG, "uid " + uid + " sent too many Binder proxies to uid " + Process.myUid()); } }, mMainHandler); } // Bind the dump service so we can dump extra info during a bug report startServiceAsUser( new Intent(getApplicationContext(), SystemUIAuxiliaryDumpService.class), UserHandle.SYSTEM); }
frameworks\base\packages\SystemUI\src\com\android\systemui\SystemUIApplication.java
public void startServicesIfNeeded() { String[] names = SystemUIFactory.getInstance().getSystemUIServiceComponents(getResources()); startServicesIfNeeded(/* metricsPrefix= */ "StartServices", names); }
调用 mServices[i].start();启动service
private void startServicesIfNeeded(String metricsPrefix, String[] services) { if (mServicesStarted) { return; } mServices = new SystemUI[services.length]; if (!mBootCompleteCache.isBootComplete()) { // check to see if maybe it was already completed long before we began // see ActivityManagerService.finishBooting() if ("1".equals(SystemProperties.get("sys.boot_completed"))) { mBootCompleteCache.setBootComplete(); if (DEBUG) { Log.v(TAG, "BOOT_COMPLETED was already sent"); } } } final DumpManager dumpManager = mRootComponent.createDumpManager(); Log.v(TAG, "Starting SystemUI services for user " + Process.myUserHandle().getIdentifier() + "."); TimingsTraceLog log = new TimingsTraceLog("SystemUIBootTiming", Trace.TRACE_TAG_APP); log.traceBegin(metricsPrefix); final int N = services.length; for (int i = 0; i < N; i++) { String clsName = services[i]; if (DEBUG) Log.d(TAG, "loading: " + clsName); log.traceBegin(metricsPrefix + clsName); long ti = System.currentTimeMillis(); try { SystemUI obj = mComponentHelper.resolveSystemUI(clsName); if (obj == null) { Constructor constructor = Class.forName(clsName).getConstructor(Context.class); obj = (SystemUI) constructor.newInstance(this); } mServices[i] = obj; } catch (ClassNotFoundException | NoSuchMethodException | IllegalAccessException | InstantiationException | InvocationTargetException ex) { throw new RuntimeException(ex); } if (DEBUG) Log.d(TAG, "running: " + mServices[i]); mServices[i].start(); log.traceEnd(); // Warn if initialization of component takes too long ti = System.currentTimeMillis() - ti; if (ti > 1000) { Log.w(TAG, "Initialization of " + clsName + " took " + ti + " ms"); } if (mBootCompleteCache.isBootComplete()) { mServices[i].onBootCompleted(); } dumpManager.registerDumpable(mServices[i].getClass().getName(), mServices[i]); } mRootComponent.getInitController().executePostInitTasks(); log.traceEnd(); mServicesStarted = true; }
mContext 是SystemUI
frameworks\base\packages\SystemUI\src\com\android\systemui\SystemUIFactory.java
/** Returns the list of system UI components that should be started. */ public String[] getSystemUIServiceComponents(Resources resources) { return resources.getStringArray(R.array.config_systemUIServiceComponents); }
frameworks\base\packages\SystemUI\res\values\config.xml
<!-- SystemUI Services: The classes of the stuff to start. --> <string-array name="config_systemUIServiceComponents" translatable="false"> <item>com.android.systemui.util.NotificationChannels</item> <item>com.android.systemui.keyguard.KeyguardViewMediator</item> <item>com.android.systemui.recents.Recents</item> <item>com.android.systemui.volume.VolumeUI</item> <item>com.android.systemui.stackdivider.Divider</item> <item>com.android.systemui.statusbar.phone.StatusBar</item> <item>com.android.systemui.usb.StorageNotification</item> <item>com.android.systemui.power.PowerUI</item> <item>com.android.systemui.media.RingtonePlayer</item> <item>com.android.systemui.keyboard.KeyboardUI</item> <item>com.android.systemui.pip.PipUI</item> <item>com.android.systemui.shortcut.ShortcutKeyDispatcher</item> <item>@string/config_systemUIVendorServiceComponent</item> <item>com.android.systemui.util.leak.GarbageMonitor$Service</item> <item>com.android.systemui.LatencyTester</item> <item>com.android.systemui.globalactions.GlobalActionsComponent</item> <item>com.android.systemui.ScreenDecorations</item> <item>com.android.systemui.biometrics.AuthController</item> <item>com.android.systemui.SliceBroadcastRelayHandler</item> <item>com.android.systemui.SizeCompatModeActivityController</item> <item>com.android.systemui.statusbar.notification.InstantAppNotifier</item> <item>com.android.systemui.theme.ThemeOverlayController</item> <item>com.android.systemui.accessibility.WindowMagnification</item> <item>com.android.systemui.accessibility.SystemActions</item> <item>com.android.systemui.toast.ToastUI</item> </string-array>
所有UI均继承自systemUI
frameworks\base\packages\SystemUI\src\com\android\systemui\SystemUI.java
public class PowerUI extends SystemUI implements CommandQueue.Callbacks {
