SystemUI启动流程

SystemUI启动流程

1. frameworks/base/services/java/com/android/server/SystemServer.java

   public final class SystemServer { 
       private static final TimingsTraceLog BOOT_TIMINGS_TRACE_LOG;
       private SystemServiceManager mSystemServiceManager;
       
       public static void main(String[] args) {
            new SystemServer().run();
       }
       private void run() {
           ...
           // Start services.
           try {
               startBootstrapServices();
           }catch(){...}
       }
       
       private void startBootstrapServices() {
           ...
           // TODO: Might need to move after migration to WM.
         ActivityTaskManagerService atm =
           mSystemServiceManager.startService(ActivityTaskManagerService.Lifecycle.class).getService();
           mActivityManagerService = ActivityManagerService.Lifecycle.startService(
                   mSystemServiceManager, atm);
           mActivityManagerService.setSystemServiceManager(mSystemServiceManager);
           mActivityManagerService.setInstaller(installer);
           mWindowManagerGlobalLock = atm.getGlobalLock();
           traceEnd();
       }
   ​
   }
       mActivityManagerService.systemReady(() -> {
       traceBeginAndSlog("StartSystemUI");
               try {
                   startSystemUi(context, windowManagerF);
               } catch (Throwable e) {
                   reportWtf("starting System UI", e);
               }
               traceEnd();
       },BOOT_TIMINGS_TRACE_LOG);
                                       
     
   //正式启动SystemUi  入口：com.android.systemui.SystemUIService.java
       private static void startSystemUi(Context context, WindowManagerService windowManager) {
           Intent intent = new Intent();
           intent.setComponent(new ComponentName("com.android.systemui","com.android.systemui.SystemUIService"));
           intent.addFlags(Intent.FLAG_DEBUG_TRIAGED_MISSING);
           //Slog.d(TAG, "Starting service: " + intent);
           context.startServiceAsUser(intent, UserHandle.SYSTEM);
           windowManager.onSystemUiStarted();
       }
      

2. 启动SystemUIService： com.android.systemui.SystemUIService.java

   public class SystemUIService extends Service {
   ​
       @Override
       public void onCreate() {
           super.onCreate();    
           ((SystemUIApplication)getApplication()).startServicesIfNeeded();
           }
   }
           

3. com.android.systemui.SystemUIApplication.java

   public class SystemUIApplication extends Application implements SysUiServiceProvider {
       private SystemUI[] mServices;
       
        @Override
       public void onCreate() {
           super.onCreate();
            SystemUIFactory.createFromConfig(this);
       }
       public void startServicesIfNeeded() { //系统服务（SystemUiservice启动时执行该方法
           String[] names = getResources().getStringArray(R.array.config_systemUIServiceComponents);
           startServicesIfNeeded(names);
       }
       private void startServicesIfNeeded(String[] services) {
            mServices = new SystemUI[services.length];
           final int N = services.length;
           //反射机制，获取SysUI对象，对象列表所在数组：R.array.config_systemUIServiceComponents
   ​
           for (int i = 0; i < N; i++) {
               String clsName = services[i];
               if (DEBUG) Log.d(TAG, "loading: " + clsName);
               log.traceBegin("StartServices" + clsName);
               long ti = System.currentTimeMillis();
               Class cls;
               try {
                   cls = Class.forName(clsName);
                   Object o = cls.newInstance();
                   if (o instanceof SystemUI.Injector) {
                       o = ((SystemUI.Injector) o).apply(this);
                   }
                   mServices[i] = (SystemUI) o;//Dependency$DependencyCreator+NotificationChannels.java
               }catch(){..}
               mServices[i].mContext = this;
               mServices[i].mComponents = mComponents;
               mServices[i].start();//反射结果.start()  //SysUI组件extends SystemUI ,通过start()方法启动
              
           }
           //添加插件:OverLayPlugin.java
           Dependency.get(PluginManager.class).addPluginListener(..,OverlayPlugin.class, true)
       }
   }

4. SystemUI子类，入口：start()

   1. NotificationChannels.java
   public class NotificationChannels extends SystemUI {
       public Context mContext;
       
       @Override
       public void start() {
           createAll(mContext);
       }
   }
   2.KeyguardViewMediator.java
   public class KeyguardViewMediator extends SystemUI {
        @Override
       public void start() {
           synchronized (this) {
               setupLocked();
           }
           putComponent(KeyguardViewMediator.class, this);
       }
   }
   .....    
   ​

5. 通过反射获取的SystemUI子类：xml文件中的数组

   <!-- SystemUI Services: The classes of the stuff to start. -->
       <string-array name="config_systemUIServiceComponents" translatable="false">
           <item>com.android.systemui.Dependency$DependencyCreator</item>  //依赖
           <item>com.android.systemui.util.NotificationChannels</item>  //创建SystemUI的通知Channel
           <item>com.android.systemui.statusbar.CommandQueue$CommandQueueStart</item>
           <item>com.android.systemui.keyguard.KeyguardViewMediator</item>  
           <item>com.android.systemui.recents.Recents</item> //最近任务
           <item>com.android.systemui.volume.VolumeUI</item>  //音量面板
           <item>com.android.systemui.stackdivider.Divider</item> //分屏
           <item>com.android.systemui.SystemBars</item>
            <item>com.android.systemui.usb.StorageNotification</item> //存储设备相关通知
           <item>com.android.systemui.power.PowerUI</item>   //低电量提醒
           <item>com.android.systemui.media.RingtonePlayer</item>   //手机铃声
           <item>com.android.systemui.keyboard.KeyboardUI</item>  //键盘
           <item>com.android.systemui.pip.PipUI</item> //画中画
           <item>com.android.systemui.shortcut.ShortcutKeyDispatcher</item>
           <item>@string/config_systemUIVendorServiceComponent</item>
           <item>com.android.systemui.util.leak.GarbageMonitor$Service</item> //定期检查SystemUI堆内存并报告
           <item>com.android.systemui.LatencyTester</item> //  在DEBUGGABLE版本运行，用于测试系统中的延迟
           <item>com.android.systemui.globalactions.GlobalActionsComponent</item> // 关机菜单
           <item>com.android.systemui.ScreenDecorations</item> //手机屏幕屏切圆角，模拟刘海屏
           <item>com.android.systemui.biometrics.BiometricDialogImpl</item>
           <item>com.android.systemui.SliceBroadcastRelayHandler</item>
           <item>com.android.systemui.SizeCompatModeActivityController</item>
           <item>com.android.systemui.statusbar.notification.InstantAppNotifier</item>  //显示Instant Apps（用户设备不需要安装的应用）的通知
           <item>com.android.systemui.theme.ThemeOverlayController</item>
           
       </string-array>
   

6.