Android之SystemUI加载流程和NavigationBar的分析

Android之SystemUI加载流程和NavigationBar的分析

本篇只分析SystemUI的加载过程和SystemUI的其中的一个模块StatusBar的小模块NavigationBar，以Android6.0代码进行分析

https://www.2cto.com/kf/201604/499625.html  挺详细的吧，懒得自己写了

 

AndroidManifest.xml

 

1 2 3 4 5 6 7 8 9 10 11

"true" android:name="SystemUIService">

SystemUIService

跟StatusBar相关的服务为SystemUIService,我们查看SystemUIService源码

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

public class SystemUIService extends Service {       @Override     public void onCreate() {         super.onCreate();         ((SystemUIApplication) getApplication()).startServicesIfNeeded();         //获取Application调用startServicesIfNeeded     }       @Override     public IBinder onBind(Intent intent) {         return null;     }       /*打印堆栈信息*/     @Override     protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) {         SystemUI[] services = ((SystemUIApplication) getApplication()).getServices();         if (args == null || args.length == 0) {             for (SystemUI ui: services) {                 pw.println("dumping service: " + ui.getClass().getName());                 ui.dump(fd, pw, args);             }         } else {             String svc = args[0];             for (SystemUI ui: services) {                 String name = ui.getClass().getName();                 if (name.endsWith(svc)) {                     ui.dump(fd, pw, args);                 }             }         }     } }

分析SystemUIService代码，可以知道SystemUI主要做了两件事

获取Application对象加载SystemUI相关的类，这个等下分析SystemUIApplication代码可以知道 dump打印SystenUISerice运行过程中相关的堆栈信息

那么SystemUIService又是哪里开始启动的呢？竟然SystemUIService是个服务，那么启动服务要么就是startService
要么就是bindService进行启动，其启动方式则需要通过Intent来传入类名或者包名，因此在源码中搜索SystemUIService可以对比发现，它在
frameworks\base\services\java\com\android\server\SystemServer.java中进行启动

?

1 2 3 4 5 6 7

static final void startSystemUi(Context context) {     Intent intent = new Intent();     intent.setComponent(new ComponentName("com.android.systemui",                 "com.android.systemui.SystemUIService"));     //Slog.d(TAG, "Starting service: " + intent);     context.startServiceAsUser(intent, UserHandle.OWNER); }

在SystemServer的run方法中startOtherServices来启动SystemUIService服务，至于SystemServer则涉及到Android的启动流程，其大概流程为

?

1 2	int -> ServerManager -> Zygote -> SystemServer

SystemServer中会初始化一些Android的java层的服务，如ActivityManagerService、WindowManagerService等

这里SystemUI的加载过程就到此告一段落了，下面分析StatusBar的加载流程

上面讲到在SystemUIService的onCreate中获取SystemUIApplication对象来初始化SystemUI相关的类，这些类里面就包括了StatusBar相关的类，我们查看SystemUIApplication类

SystemUIApplication

onCreate

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

@Override public void onCreate() {     super.onCreate();     // Set the application theme that is inherited by all services. Note that setting the     // application theme in the manifest does only work for activities. Keep this in sync with     // the theme set there.     setTheme(R.style.systemui_theme);     //注释广播     IntentFilter filter = new IntentFilter(Intent.ACTION_BOOT_COMPLETED);     filter.setPriority(IntentFilter.SYSTEM_HIGH_PRIORITY);     registerReceiver(new BroadcastReceiver() {         @Override         public void onReceive(Context context, Intent intent) {             //开启直接返回             if (mBootCompleted) return;               if (DEBUG) Log.v(TAG, "BOOT_COMPLETED received");             unregisterReceiver(this);             //标记启动             mBootCompleted = true;             //服务是否启动             if (mServicesStarted) {                 final int N = mServices.length;                 for (int i = 0; i < N; i++) {                     //回调各服务的onBootCompleted函数                     mServices[i].onBootCompleted();                 }             }         }     }, filter); }

在SystemUIApplication的onCreate中主要做了

设置主题（这个会影响其SystemUI的界面显示效果） 注册开机广播，设置标志位

startServicesIfNeeded

SystemUIService中的onCreate启动了这个方法，我们着重分析这个方法

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

public void startServicesIfNeeded() {     if (mServicesStarted) {         return;     }       if (!mBootCompleted) {         // check to see if maybe it was already completed long before we began         // see ActivityManagerService.finishBooting()         //获取系统文件中的sys.boot_completed的值         if ("1".equals(SystemProperties.get("sys.boot_completed"))) {             mBootCompleted = true;             if (DEBUG) Log.v(TAG, "BOOT_COMPLETED was already sent");         }     }       Log.v(TAG, "Starting SystemUI services.");     final int N = SERVICES.length;     for (int i=0; i cl = SERVICES[i];         if (DEBUG) Log.d(TAG, "loading: " + cl);         //实例化各个类实例，放入mServices数组中         try {             mServices[i] = (SystemUI)cl.newInstance();         } catch (IllegalAccessException ex) {             throw new RuntimeException(ex);         } catch (InstantiationException ex) {             throw new RuntimeException(ex);         }         mServices[i].mContext = this;         mServices[i].mComponents = mComponents;         if (DEBUG) Log.d(TAG, "running: " + mServices[i]);         mServices[i].start();           if (mBootCompleted) {             mServices[i].onBootCompleted();         }     }     //服务启动标志     mServicesStarted = true; }

这个方法中，首先判断mServicesStarted标志为来判断SystemUI相关的服务是否启动，同时根据系统配置文件来检查ActivityManagerService是否finishBooting，然后通过类加载机制来初始化SERVICES数组里面相关的类加入mServices中，然后start

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

/**  * The classes of the stuff to start.  */ private final Class[] SERVICES = new Class[] {         com.android.systemui.tuner.TunerService.class,//定制状态栏服务         com.android.systemui.keyguard.KeyguardViewMediator.class,//锁屏相关         com.android.systemui.recents.Recents.class,//近期任务         com.android.systemui.volume.VolumeUI.class,//音量条         com.android.systemui.statusbar.SystemBars.class,//状态栏         com.android.systemui.usb.StorageNotification.class,//通知栏         com.android.systemui.power.PowerUI.class,//电源相关         com.android.systemui.media.RingtonePlayer.class,//铃声播放相关 };   /**  * Hold a reference on the stuff we start.  */ private final SystemUI[] mServices = new SystemUI[SERVICES.length];

从mServices和SERVICES的定义可以发现SERVICES是一组包含全路径的相关的类,这些类包含一些我们常见的TunerService（定制状态栏服务）、
KeyguardViewMediator（锁屏相关）、Recents(近期任务)、VolumeUI(音量条)、SystemBars(状态栏)、StorageNotification（通知栏）、PowerUI（电源相关）、RingtonePlayer（铃声播放相关）类，它们都是继承与SystemUI抽象类，现在只分析StatusBar相关的SystemBars类

SystemBars

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82

public class SystemBars extends SystemUI implements ServiceMonitor.Callbacks {     private static final String TAG = "SystemBars";     private static final boolean DEBUG = false;     private static final int WAIT_FOR_BARS_TO_DIE = 500;       // manages the implementation coming from the remote process     private ServiceMonitor mServiceMonitor;       // in-process fallback implementation, per the product config     private BaseStatusBar mStatusBar;       @Override     public void start() {         if (DEBUG) Log.d(TAG, "start");         //实例化ServiceMonitor         mServiceMonitor = new ServiceMonitor(TAG, DEBUG,                 mContext, Settings.Secure.BAR_SERVICE_COMPONENT, this);         //start         mServiceMonitor.start();  // will call onNoService if no remote service is found     }     /*服务没启动时，ServiceMonitor会回调onNoService*/     @Override     public void onNoService() {         if (DEBUG) Log.d(TAG, "onNoService");         createStatusBarFromConfig();  // fallback to using an in-process implementation     }     /*服务已经启动的回调*/     @Override     public long onServiceStartAttempt() {         if (DEBUG) Log.d(TAG, "onServiceStartAttempt mStatusBar="+mStatusBar);         if (mStatusBar != null) {             // tear down the in-process version, we'll recreate it again if needed             mStatusBar.destroy();             mStatusBar = null;             return WAIT_FOR_BARS_TO_DIE;         }         return 0;     }     /*系统配置改变*/     @Override     protected void onConfigurationChanged(Configuration newConfig) {         if (mStatusBar != null) {             mStatusBar.onConfigurationChanged(newConfig);         }     }     /*打印堆栈*/     @Override     public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {         if (mStatusBar != null) {             mStatusBar.dump(fd, pw, args);         }     }     /*从xml文件中获取PhoneStatusBar全路径，通过类加载器实例化类，调用其start*/     private void createStatusBarFromConfig() {         if (DEBUG) Log.d(TAG, "createStatusBarFromConfig");         final String clsName = mContext.getString(R.string.config_statusBarComponent);         if (clsName == null || clsName.length() == 0) {             throw andLog("No status bar component configured", null);         }         Class cls = null;         try {             cls = mContext.getClassLoader().loadClass(clsName);         } catch (Throwable t) {             throw andLog("Error loading status bar component: " + clsName, t);         }         try {             mStatusBar = (BaseStatusBar) cls.newInstance();         } catch (Throwable t) {             throw andLog("Error creating status bar component: " + clsName, t);         }         mStatusBar.mContext = mContext;         mStatusBar.mComponents = mComponents;         mStatusBar.start();         if (DEBUG) Log.d(TAG, "started " + mStatusBar.getClass().getSimpleName());     }       private RuntimeException andLog(String msg, Throwable t) {         Log.w(TAG, msg, t);         throw new RuntimeException(msg, t);     } }

我们先从start方法开始分析

?

1 2 3 4 5 6 7 8

@Override     public void start() {         if (DEBUG) Log.d(TAG, "start");         mServiceMonitor = new ServiceMonitor(TAG, DEBUG,                 mContext, Settings.Secure.BAR_SERVICE_COMPONENT, this);         mServiceMonitor.start();  // will call onNoService if no remote service is found     }

这里实例化ServiceMonitor类start，继续分析ServiceMonitor

ServiceMonitor

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

class="hljs r">    ...     public ServiceMonitor(String ownerTag, boolean debug,             Context context, String settingKey, Callbacks callbacks) {         mTag = ownerTag + ".ServiceMonitor";         mDebug = debug;         mContext = context;         mSettingKey = settingKey; // Settings.Secure.BAR_SERVICE_COMPONENT         mCallbacks = callbacks;     }       public void start() {         // listen for setting changes         /*Settings.Secure.BAR_SERVICE_COMPONENT改变时回调*/         ContentResolver cr = mContext.getContentResolver();         cr.registerContentObserver(Settings.Secure.getUriFor(mSettingKey),                 false /*notifyForDescendents*/, mSettingObserver, UserHandle.USER_ALL);           // listen for package/component changes         //应用安装，改变，卸载会触发mBroadcastReceiver广播         IntentFilter filter = new IntentFilter();         filter.addAction(Intent.ACTION_PACKAGE_ADDED);         filter.addAction(Intent.ACTION_PACKAGE_CHANGED);         filter.addAction(Intent.ACTION_PACKAGE_REMOVED);         filter.addDataScheme("package");         mContext.registerReceiver(mBroadcastReceiver, filter);           mHandler.sendEmptyMessage(MSG_START_SERVICE);     }     ...

ServiceMOnitor是一个监听Settings.Secure.BAR_SERVICE_COMPONENT是否改变的类，在start中通过监听系统系统时应用的变化来启动服务

?

1 2 3 4 5 6 7 8 9

private final BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {     public void onReceive(Context context, Intent intent) {         String pkg = intent.getData().getSchemeSpecificPart();         if (mServiceName != null && mServiceName.getPackageName().equals(pkg)) {             mHandler.sendMessage(mHandler.obtainMessage(MSG_PACKAGE_INTENT, intent));         }     } };

应用装载时，通过Handler发送MSG_PACKAGE_INTENT消息事件，我们查看Handler消息回调

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

class="hljs java">    // internal handler + messages used to serialize access to internal state     public static final int MSG_START_SERVICE = 1; //启动服务，并非真正启动，会根据ServiceName进行判断     public static final int MSG_CONTINUE_START_SERVICE = 2; //启动服务     public static final int MSG_STOP_SERVICE = 3;//停止服务消息     public static final int MSG_PACKAGE_INTENT = 4;//包安装事件消息     public static final int MSG_CHECK_BOUND = 5;//包改变或者卸载时，重新启动服务消息     public static final int MSG_SERVICE_DISCONNECTED = 6;//服务断开消息       private final Handler mHandler = new Handler() {         public void handleMessage(Message msg) {             switch(msg.what) {                 case MSG_START_SERVICE:                     startService();                     break;                 case MSG_CONTINUE_START_SERVICE:                     continueStartService();                     break;                 case MSG_STOP_SERVICE:                     stopService();                     break;                 case MSG_PACKAGE_INTENT:                     packageIntent((Intent)msg.obj);                     break;                 case MSG_CHECK_BOUND:                     checkBound();                     break;                 case MSG_SERVICE_DISCONNECTED:                     serviceDisconnected((ComponentName)msg.obj);                     break;             }         }     };       private void packageIntent(Intent intent) {         if (mDebug) Log.d(mTag, "packageIntent intent=" + intent                 + " extras=" + bundleToString(intent.getExtras()));         if (Intent.ACTION_PACKAGE_ADDED.equals(intent.getAction())) {             mHandler.sendEmptyMessage(MSG_START_SERVICE);//发送启动服务消息         } else if (Intent.ACTION_PACKAGE_CHANGED.equals(intent.getAction())                 || Intent.ACTION_PACKAGE_REMOVED.equals(intent.getAction())) {             final PackageManager pm = mContext.getPackageManager();             final boolean serviceEnabled = isPackageAvailable()                     && pm.getApplicationEnabledSetting(mServiceName.getPackageName())                             != PackageManager.COMPONENT_ENABLED_STATE_DISABLED                     && pm.getComponentEnabledSetting(mServiceName)                             != PackageManager.COMPONENT_ENABLED_STATE_DISABLED;             if (mBound && !serviceEnabled) {                 stopService();                 scheduleCheckBound();             } else if (!mBound && serviceEnabled) {                 startService();             }         }     }

当我们SystemUI应用检测到有新应用装载时，会发送MSG_START_SERVICE消息来启动服务，我们接着分析Handler的回调MSG_START_SERVICE消息

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

class="hljs cs">    private void startService() {         mServiceName = getComponentNameFromSetting();         if (mDebug) Log.d(mTag, "startService mServiceName=" + mServiceName);         if (mServiceName == null) {             mBound = false;             mCallbacks.onNoService();         } else {             long delay = mCallbacks.onServiceStartAttempt();             mHandler.sendEmptyMessageDelayed(MSG_CONTINUE_START_SERVICE, delay);         }     }     /*从ContentProvider数据库中取得包名*/     private ComponentName getComponentNameFromSetting() {         String cn = Settings.Secure.getStringForUser(mContext.getContentResolver(),                 mSettingKey, UserHandle.USER_CURRENT);         return cn == null ? null : ComponentName.unflattenFromString(cn);     }

首先从ContentProvider数据库中取得包名，如果没有启动，则回调CallBaback的onNoService服务，否则发送MSG_CONTINUE_START_SERVICE消息启动服务

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14

class="hljs cs">    private void continueStartService() {         if (mDebug) Log.d(mTag, "continueStartService");         Intent intent = new Intent().setComponent(mServiceName);         try {             mServiceConnection = new SC();             mBound = mContext.bindService(intent, mServiceConnection, Context.BIND_AUTO_CREATE);             if (mDebug) Log.d(mTag, "mBound: " + mBound);         } catch (Throwable t) {             Log.w(mTag, "Error binding to service: " + mServiceName, t);         }         if (!mBound) {             mCallbacks.onNoService();         }     }

至此可以知道，当远程服务没有启动时，会回调SystemBar的onNoService函数，我们回到SystemBar，分析onNoService函数

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

class="hljs java">     ...      @Override         public void onNoService() {             if (DEBUG) Log.d(TAG, "onNoService");             createStatusBarFromConfig();  // fallback to using an in-process implementation         }      ...      private void createStatusBarFromConfig() {         if (DEBUG) Log.d(TAG, "createStatusBarFromConfig");         final String clsName = mContext.getString(R.string.config_statusBarComponent);//从xml文件读取类名         if (clsName == null || clsName.length() == 0) {             throw andLog("No status bar component configured", null);         }         //通过类加载器实例化类         Class cls = null;         try {             cls = mContext.getClassLoader().loadClass(clsName);         } catch (Throwable t) {             throw andLog("Error loading status bar component: " + clsName, t);         }         try {             mStatusBar = (BaseStatusBar) cls.newInstance();         } catch (Throwable t) {             throw andLog("Error creating status bar component: " + clsName, t);         }         mStatusBar.mContext = mContext;         mStatusBar.mComponents = mComponents;         mStatusBar.start();//调用类的start方法         if (DEBUG) Log.d(TAG, "started " + mStatusBar.getClass().getSimpleName());     }

上面分析可以得知，当远程服务没有启动时，首先从xml文件读取要启动的类名，我们来查看这个xml文件
res\values\config.xml

?

1 2 3

class="hljs xml">        "config_statusBarComponent" translatable="false">com.android.systemui.statusbar.phone.PhoneStatusBar

从上面可以知道，最终程序会加载PhoneStatusBar这个类，接下来分析PhoneStatusBar

PhoneStatusBar

首先我们从上面分析得知，当实例化PhoneStatusBar类后会调用start方法，我们就从PhoneStatusBar的start方法开始分析

start

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58

class="hljs avrasm">    ...     @Override     public void start() {         //获取WindowManager，初始化当前显示界面大小         mDisplay = ((WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE))                 .getDefaultDisplay();         updateDisplaySize();         //src绘图模式         mScrimSrcModeEnabled = mContext.getResources().getBoolean(                 R.bool.config_status_bar_scrim_behind_use_src);         //调用父类start方法         super.start(); // calls createAndAddWindows()         //MediaSession相关         mMediaSessionManager                 = (MediaSessionManager) mContext.getSystemService(Context.MEDIA_SESSION_SERVICE);         // TODO: use MediaSessionManager.SessionListener to hook us up to future updates         // in session state         //添加导航栏         addNavigationBar();           // Lastly, call to the icon policy to install/update all the icons.         //更新状态栏图标         mIconPolicy = new PhoneStatusBarPolicy(mContext, mCastController, mHotspotController,                 mUserInfoController, mBluetoothController);         mIconPolicy.setCurrentUserSetup(mUserSetup);         mSettingsObserver.onChange(false); // set up           mHeadsUpObserver.onChange(true); // set up         if (ENABLE_HEADS_UP) {             mContext.getContentResolver().registerContentObserver(                     Settings.Global.getUriFor(Settings.Global.HEADS_UP_NOTIFICATIONS_ENABLED), true,                     mHeadsUpObserver);             mContext.getContentResolver().registerContentObserver(                     Settings.Global.getUriFor(SETTING_HEADS_UP_TICKER), true,                     mHeadsUpObserver);         }         mUnlockMethodCache = UnlockMethodCache.getInstance(mContext);         mUnlockMethodCache.addListener(this);         //锁屏         startKeyguard();           mDozeServiceHost = new DozeServiceHost();         KeyguardUpdateMonitor.getInstance(mContext).registerCallback(mDozeServiceHost);         putComponent(DozeHost.class, mDozeServiceHost);         putComponent(PhoneStatusBar.class, this);           /// M:add for multi window @{         if(MultiWindowProxy.isSupported()) {             registerMWProxyAgain();         }         /// @}         setControllerUsers();           notifyUserAboutHiddenNotifications();           mScreenPinningRequest = new ScreenPinningRequest(mContext);     }     ...

我们接着分析PhoneStatusBar父类的BaseStatusBar的start方法

BaseStatusBar

start

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80

class="hljs cs">    ...     public void start() {         //获取Dispaly         mWindowManager = (WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE);         mWindowManagerService = WindowManagerGlobal.getWindowManagerService();         mDisplay = mWindowManager.getDefaultDisplay();         mDevicePolicyManager = (DevicePolicyManager)mContext.getSystemService(                 Context.DEVICE_POLICY_SERVICE);           mNotificationColorUtil = NotificationColorUtil.getInstance(mContext);           mNotificationData = new NotificationData(this);           mAccessibilityManager = (AccessibilityManager)                 mContext.getSystemService(Context.ACCESSIBILITY_SERVICE);           mDreamManager = IDreamManager.Stub.asInterface(                 ServiceManager.checkService(DreamService.DREAM_SERVICE));         mPowerManager = (PowerManager) mContext.getSystemService(Context.POWER_SERVICE);         //监听设置文件的改变，以便更新ContenProvider数据库         mContext.getContentResolver().registerContentObserver(                 Settings.Global.getUriFor(Settings.Global.DEVICE_PROVISIONED), true,                 mSettingsObserver);         mContext.getContentResolver().registerContentObserver(                 Settings.Global.getUriFor(Settings.Global.ZEN_MODE), false,                 mSettingsObserver);         mContext.getContentResolver().registerContentObserver(                 Settings.Secure.getUriFor(Settings.Secure.LOCK_SCREEN_SHOW_NOTIFICATIONS), false,                 mSettingsObserver,                 UserHandle.USER_ALL);           mContext.getContentResolver().registerContentObserver(                 Settings.Secure.getUriFor(Settings.Secure.LOCK_SCREEN_ALLOW_PRIVATE_NOTIFICATIONS),                 true,                 mLockscreenSettingsObserver,                 UserHandle.USER_ALL);         //加载startbarService服务         mBarService = IStatusBarService.Stub.asInterface(                 ServiceManager.getService(Context.STATUS_BAR_SERVICE));         //设置近期任务回调         mRecents = getComponent(Recents.class);         mRecents.setCallback(this);         //获取本地配置         final Configuration currentConfig = mContext.getResources().getConfiguration();         mLocale = currentConfig.locale;         mLayoutDirection = TextUtils.getLayoutDirectionFromLocale(mLocale);         mFontScale = currentConfig.fontScale;           mUserManager = (UserManager) mContext.getSystemService(Context.USER_SERVICE);         //加载动画         mLinearOutSlowIn = AnimationUtils.loadInterpolator(mContext,                 android.R.interpolator.linear_out_slow_in);         mFastOutLinearIn = AnimationUtils.loadInterpolator(mContext,                 android.R.interpolator.fast_out_linear_in);           // Connect in to the status bar manager service         StatusBarIconList iconList = new StatusBarIconList();         mCommandQueue = new CommandQueue(this, iconList);           int[] switches = new int[8];         ArrayList binders = new ArrayList();         try {             mBarService.registerStatusBar(mCommandQueue, iconList, switches, binders);         } catch (RemoteException ex) {             // If the system process isn't there we're doomed anyway.         }         //调用createAndAddWindows方法         createAndAddWindows();           mSettingsObserver.onChange(false); // set up         disable(switches[0], switches[6], false /* animate */);         setSystemUiVisibility(switches[1], 0xffffffff);         topAppWindowChanged(switches[2] != 0);         // StatusBarManagerService has a back up of IME token and it's restored here.         setImeWindowStatus(binders.get(0), switches[3], switches[4], switches[5] != 0);           // Set up the initial icon state         int N = iconList.size();         int viewIndex = 0;         for (int i=0; i"" {="" statusbaricon="" icon="iconList.getIcon(i);" if="" (icon="" !="null)" addicon(iconlist.getslot(i),="" i,="" viewindex,="" icon);="" viewindex++;="" }="" set="" up="" the="" initial="" notification="" state.="" try="" mnotificationlistener.registerassystemservice(mcontext,="" new="" componentname(mcontext.getpackagename(),="" getclass().getcanonicalname()),="" userhandle.user_all);="" catch="" (remoteexception="" e)="" log.e(tag,="" "unable="" to="" register="" listener",="" e);="" (debug)="" log.d(tag,="" string.format(="" "init:="" icons="%d" disabled="0x%08x" lights="0x%08x" menu="0x%08x" imebutton="0x%08x"," iconlist.size(),="" switches[0],="" switches[1],="" switches[2],="" switches[3]="" ));="" mcurrentuserid="ActivityManager.getCurrentUser();" setheadsupuser(mcurrentuserid);="" intentfilter="" filter="new" intentfilter();="" filter.addaction(intent.action_user_switched);="" filter.addaction(intent.action_user_added);="" filter.addaction(intent.action_user_present);="" filter.addaction(banner_action_cancel);="" filter.addaction(banner_action_setup);="" mcontext.registerreceiver(mbroadcastreceiver,="" filter);="" allusersfilter="new" allusersfilter.addaction(="" devicepolicymanager.action_device_policy_manager_state_changed);="" mcontext.registerreceiverasuser(mallusersreceiver,="" userhandle.all,="" allusersfilter,="" null,="" null);="" updatecurrentprofilescache();="" ...

BaseStatusBar关于StatusBar相关的最主要是调用了createAndAddWindows方法，我们看下这个方法的定义

?

1 2 3 4 5

class="hljs cs">class="hljs java">    /**      * Create all windows necessary for the status bar (including navigation, overlay panels, etc)      * and add them to the window manager.      */     protected abstract void createAndAddWindows();

这是一个抽象方法，也就是说，它会回调到子类的createAndAddWindows的实现方法中，我们重新回到PhoneStatusBar中，找到createAndAddWindows的方法实现

createAndAddWindows

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364

class="hljs cs">class="hljs avrasm">    ...     @Override     public void createAndAddWindows() {         addStatusBarWindow();     }       private void addStatusBarWindow() {         makeStatusBarView();//创建statusbar视图         mStatusBarWindowManager = new StatusBarWindowManager(mContext);         //通过StatusBarWindowManager类的add方法加载到Window窗体中         mStatusBarWindowManager.add(mStatusBarWindow, getStatusBarHeight());     }     ...     protected PhoneStatusBarView makeStatusBarView() {         final Context context = mContext;         //通过Resources更新显示大小和一些资源文件         Resources res = context.getResources();           updateDisplaySize(); // populates mDisplayMetrics         updateResources();         //加载StartBarWindowView视图         mStatusBarWindow = (StatusBarWindowView) View.inflate(context,                 R.layout.super_status_bar, null);         mStatusBarWindow.setService(this);         //监听下拉事件         mStatusBarWindow.setOnTouchListener(new View.OnTouchListener() {             @Override             public boolean onTouch(View v, MotionEvent event) {                 checkUserAutohide(v, event);                 if (event.getAction() == MotionEvent.ACTION_DOWN) {                     if (mExpandedVisible) {                         animateCollapsePanels();                     }                 }                 return mStatusBarWindow.onTouchEvent(event);             }         });         //状态栏         mStatusBarView = (PhoneStatusBarView) mStatusBarWindow.findViewById(R.id.status_bar);         mStatusBarView.setBar(this);         //         PanelHolder holder = (PanelHolder) mStatusBarWindow.findViewById(R.id.panel_holder);         mStatusBarView.setPanelHolder(holder);         //通知栏         mNotificationPanel = (NotificationPanelView) mStatusBarWindow.findViewById(                 R.id.notification_panel);         mNotificationPanel.setStatusBar(this);           //  M: setBackground in 512 low ram device         if (!ActivityManager.isHighEndGfx() && !FeatureOptions.LOW_RAM_SUPPORT) {             mStatusBarWindow.setBackground(null);             mNotificationPanel.setBackground(new FastColorDrawable(context.getColor(                     R.color.notification_panel_solid_background)));         }         //状态栏通知         mHeadsUpManager = new HeadsUpManager(context, mStatusBarWindow);         mHeadsUpManager.setBar(this);         mHeadsUpManager.addListener(this);         mHeadsUpManager.addListener(mNotificationPanel);         mNotificationPanel.setHeadsUpManager(mHeadsUpManager);         mNotificationData.setHeadsUpManager(mHeadsUpManager);           if (MULTIUSER_DEBUG) {             mNotificationPanelDebugText = (TextView) mNotificationPanel.findViewById(                     R.id.header_debug_info);             mNotificationPanelDebugText.setVisibility(View.VISIBLE);         }           try {             //是否显示导航栏             boolean showNav = mWindowManagerService.hasNavigationBar();              Log.v(TAG, "hasNavigationBar=" + showNav);             if (showNav) {                 /// M: add for multi window @{                 //加载导航栏布局                 int layoutId = R.layout.navigation_bar;                 if(MultiWindowProxy.isSupported()) {                     layoutId = R.layout.navigation_bar_float_window;                 }                 mNavigationBarView = (NavigationBarView) View.inflate(context,                         /*R.layout.navigation_bar*/layoutId, null);                 /// @}                   mNavigationBarView.setDisabledFlags(mDisabled1);                 mNavigationBarView.setBar(this);                 mNavigationBarView.setOnVerticalChangedListener(                         new NavigationBarView.OnVerticalChangedListener() {                     @Override                     public void onVerticalChanged(boolean isVertical) {                         if (mAssistManager != null) {                             mAssistManager.onConfigurationChanged();                         }                         mNotificationPanel.setQsScrimEnabled(!isVertical);                     }                 });                 //设置导航栏触摸事件                 mNavigationBarView.setOnTouchListener(new View.OnTouchListener() {                     @Override                     public boolean onTouch(View v, MotionEvent event) {                         checkUserAutohide(v, event);                         return false;                     }});             }         } catch (RemoteException ex) {             // no window manager? good luck with that         }           mAssistManager = new AssistManager(this, context);           // figure out which pixel-format to use for the status bar.         mPixelFormat = PixelFormat.OPAQUE;         //下拉通知栏         mStackScroller = (NotificationStackScrollLayout) mStatusBarWindow.findViewById(                 R.id.notification_stack_scroller);         mStackScroller.setLongPressListener(getNotificationLongClicker());         mStackScroller.setPhoneStatusBar(this);         mStackScroller.setGroupManager(mGroupManager);         mStackScroller.setHeadsUpManager(mHeadsUpManager);         mGroupManager.setOnGroupChangeListener(mStackScroller);           mKeyguardIconOverflowContainer =                 (NotificationOverflowContainer) LayoutInflater.from(mContext).inflate(                         R.layout.status_bar_notification_keyguard_overflow, mStackScroller, false);         mKeyguardIconOverflowContainer.setOnActivatedListener(this);         mKeyguardIconOverflowContainer.setOnClickListener(mOverflowClickListener);         mStackScroller.setOverflowContainer(mKeyguardIconOverflowContainer);           SpeedBumpView speedBump = (SpeedBumpView) LayoutInflater.from(mContext).inflate(                         R.layout.status_bar_notification_speed_bump, mStackScroller, false);         mStackScroller.setSpeedBumpView(speedBump);         mEmptyShadeView = (EmptyShadeView) LayoutInflater.from(mContext).inflate(                 R.layout.status_bar_no_notifications, mStackScroller, false);         mStackScroller.setEmptyShadeView(mEmptyShadeView);         //下拉清除键         mDismissView = (DismissView) LayoutInflater.from(mContext).inflate(                 R.layout.status_bar_notification_dismiss_all, mStackScroller, false);         mDismissView.setOnButtonClickListener(new View.OnClickListener() {             @Override             public void onClick(View v) {                 MetricsLogger.action(mContext, MetricsLogger.ACTION_DISMISS_ALL_NOTES);                 clearAllNotifications();             }         });         mStackScroller.setDismissView(mDismissView);         mExpandedContents = mStackScroller;           mBackdrop = (BackDropView) mStatusBarWindow.findViewById(R.id.backdrop);         mBackdropFront = (ImageView) mBackdrop.findViewById(R.id.backdrop_front);         mBackdropBack = (ImageView) mBackdrop.findViewById(R.id.backdrop_back);           ScrimView scrimBehind = (ScrimView) mStatusBarWindow.findViewById(R.id.scrim_behind);         ScrimView scrimInFront = (ScrimView) mStatusBarWindow.findViewById(R.id.scrim_in_front);         View headsUpScrim = mStatusBarWindow.findViewById(R.id.heads_up_scrim);         mScrimController = new ScrimController(scrimBehind, scrimInFront, headsUpScrim,                 mScrimSrcModeEnabled);         mHeadsUpManager.addListener(mScrimController);         mStackScroller.setScrimController(mScrimController);         mScrimController.setBackDropView(mBackdrop);         mStatusBarView.setScrimController(mScrimController);         mDozeScrimController = new DozeScrimController(mScrimController, context);           mHeader = (StatusBarHeaderView) mStatusBarWindow.findViewById(R.id.header);         mHeader.setActivityStarter(this);         //锁屏相关         mKeyguardStatusBar = (KeyguardStatusBarView) mStatusBarWindow.findViewById(R.id.keyguard_header);         mKeyguardStatusView = mStatusBarWindow.findViewById(R.id.keyguard_status_view);         mKeyguardBottomArea =                 (KeyguardBottomAreaView) mStatusBarWindow.findViewById(R.id.keyguard_bottom_area);         mKeyguardBottomArea.setActivityStarter(this);         mKeyguardBottomArea.setAssistManager(mAssistManager);         mKeyguardIndicationController = new KeyguardIndicationController(mContext,                 (KeyguardIndicationTextView) mStatusBarWindow.findViewById(                         R.id.keyguard_indication_text),                 mKeyguardBottomArea.getLockIcon());         mKeyguardBottomArea.setKeyguardIndicationController(mKeyguardIndicationController);           // set the inital view visibility         setAreThereNotifications();         //主要是控制一些系统图标，第三方图标等的显示和更新         mIconController = new StatusBarIconController(                 mContext, mStatusBarView, mKeyguardStatusBar, this);           // Background thread for any controllers that need it.         mHandlerThread = new HandlerThread(TAG, Process.THREAD_PRIORITY_BACKGROUND);         mHandlerThread.start();           // Other icons         //位置控制         mLocationController = new LocationControllerImpl(mContext,                 mHandlerThread.getLooper()); // will post a notification         //电池         mBatteryController = new BatteryController(mContext);         mBatteryController.addStateChangedCallback(new BatteryStateChangeCallback() {             @Override             public void onPowerSaveChanged() {                 mHandler.post(mCheckBarModes);                 if (mDozeServiceHost != null) {                     mDozeServiceHost.firePowerSaveChanged(mBatteryController.isPowerSave());                 }             }             @Override             public void onBatteryLevelChanged(int level, boolean pluggedIn, boolean charging) {                 // noop             }         });         //网络         mNetworkController = new NetworkControllerImpl(mContext, mHandlerThread.getLooper());         //热点         mHotspotController = new HotspotControllerImpl(mContext);         //蓝牙         mBluetoothController = new BluetoothControllerImpl(mContext, mHandlerThread.getLooper());         mSecurityController = new SecurityControllerImpl(mContext);         /// M: add extra tiles @{         // add HotKnot in quicksetting         if (SIMHelper.isMtkHotKnotSupport()) {             Log.d(TAG, "makeStatusBarView : HotKnotControllerImpl");             mHotKnotController = new HotKnotControllerImpl(mContext);         } else {             mHotKnotController = null;         }           // add AudioProfile in quicksetting         if (SIMHelper.isMtkAudioProfilesSupport()) {             Log.d(TAG, "makeStatusBarView : AudioProfileControllerImpl");             mAudioProfileController = new AudioProfileControllerImpl(mContext);         } else {             mAudioProfileController = null;         }           SIMHelper.setContext(mContext);         // /@}           if (mContext.getResources().getBoolean(R.bool.config_showRotationLock)) {             mRotationLockController = new RotationLockControllerImpl(mContext);         }         mUserInfoController = new UserInfoController(mContext);         mVolumeComponent = getComponent(VolumeComponent.class);         if (mVolumeComponent != null) {             mZenModeController = mVolumeComponent.getZenController();         }         Log.d(TAG, "makeStatusBarView : CastControllerImpl +");         mCastController = new CastControllerImpl(mContext);         Log.d(TAG, "makeStatusBarView : CastControllerImpl -");         final SignalClusterView signalCluster =                 (SignalClusterView) mStatusBarView.findViewById(R.id.signal_cluster);         final SignalClusterView signalClusterKeyguard =                 (SignalClusterView) mKeyguardStatusBar.findViewById(R.id.signal_cluster);         final SignalClusterView signalClusterQs =                 (SignalClusterView) mHeader.findViewById(R.id.signal_cluster);         mNetworkController.addSignalCallback(signalCluster);         mNetworkController.addSignalCallback(signalClusterKeyguard);         mNetworkController.addSignalCallback(signalClusterQs);         signalCluster.setSecurityController(mSecurityController);         signalCluster.setNetworkController(mNetworkController);         signalClusterKeyguard.setSecurityController(mSecurityController);         signalClusterKeyguard.setNetworkController(mNetworkController);         signalClusterQs.setSecurityController(mSecurityController);         signalClusterQs.setNetworkController(mNetworkController);         final boolean isAPhone = mNetworkController.hasVoiceCallingFeature();         if (isAPhone) {             mNetworkController.addEmergencyListener(mHeader);         }           /// M: Support "Operator plugin - Customize Carrier Label for PLMN" @{         mStatusBarPlmnPlugin = PluginFactory.getStatusBarPlmnPlugin(context);         if (supportCustomizeCarrierLabel()) {             mCustomizeCarrierLabel = mStatusBarPlmnPlugin.customizeCarrierLabel(                     mNotificationPanel, null);         }         /// M: Support "Operator plugin - Customize Carrier Label for PLMN" @}         //手电筒         mFlashlightController = new FlashlightController(mContext);         //键盘         mKeyguardBottomArea.setFlashlightController(mFlashlightController);         mKeyguardBottomArea.setPhoneStatusBar(this);         mKeyguardBottomArea.setUserSetupComplete(mUserSetup);         mAccessibilityController = new AccessibilityController(mContext);         mKeyguardBottomArea.setAccessibilityController(mAccessibilityController);         mNextAlarmController = new NextAlarmController(mContext);         mKeyguardMonitor = new KeyguardMonitor(mContext);         if (UserSwitcherController.isUserSwitcherAvailable(UserManager.get(mContext))) {             mUserSwitcherController = new UserSwitcherController(mContext, mKeyguardMonitor,                     mHandler);         }         mKeyguardUserSwitcher = new KeyguardUserSwitcher(mContext,                 (ViewStub) mStatusBarWindow.findViewById(R.id.keyguard_user_switcher),                 mKeyguardStatusBar, mNotificationPanel, mUserSwitcherController);             // Set up the quick settings tile panel         mQSPanel = (QSPanel) mStatusBarWindow.findViewById(R.id.quick_settings_panel);         if (mQSPanel != null) {             final QSTileHost qsh = new QSTileHost(mContext, this,                     mBluetoothController, mLocationController, mRotationLockController,                     mNetworkController, mZenModeController, mHotspotController,                     mCastController, mFlashlightController,                     mUserSwitcherController, mKeyguardMonitor,                     mSecurityController,                     /// M: add HotKnot in quicksetting                     mHotKnotController,                     /// M: add AudioProfile in quicksetting                     mAudioProfileController             );             mQSPanel.setHost(qsh);             mQSPanel.setTiles(qsh.getTiles());             mBrightnessMirrorController = new BrightnessMirrorController(mStatusBarWindow);             mQSPanel.setBrightnessMirror(mBrightnessMirrorController);             mHeader.setQSPanel(mQSPanel);             qsh.setCallback(new QSTileHost.Callback() {                 @Override                 public void onTilesChanged() {                     mQSPanel.setTiles(qsh.getTiles());                 }             });         }           // User info. Trigger first load.         mHeader.setUserInfoController(mUserInfoController);         mKeyguardStatusBar.setUserInfoController(mUserInfoController);         mKeyguardStatusBar.setUserSwitcherController(mUserSwitcherController);         mUserInfoController.reloadUserInfo();           mHeader.setBatteryController(mBatteryController);         ((BatteryMeterView) mStatusBarView.findViewById(R.id.battery)).setBatteryController(                 mBatteryController);         mKeyguardStatusBar.setBatteryController(mBatteryController);         mHeader.setNextAlarmController(mNextAlarmController);           PowerManager pm = (PowerManager) mContext.getSystemService(Context.POWER_SERVICE);         mBroadcastReceiver.onReceive(mContext,                 new Intent(pm.isScreenOn() ? Intent.ACTION_SCREEN_ON : Intent.ACTION_SCREEN_OFF));             // receive broadcasts         //注册系统广播         IntentFilter filter = new IntentFilter();         filter.addAction(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);         filter.addAction(Intent.ACTION_SCREEN_OFF);         filter.addAction(Intent.ACTION_SCREEN_ON);         context.registerReceiverAsUser(mBroadcastReceiver, UserHandle.ALL, filter, null, null);           IntentFilter demoFilter = new IntentFilter();         if (DEBUG_MEDIA_FAKE_ARTWORK) {             demoFilter.addAction(ACTION_FAKE_ARTWORK);         }         demoFilter.addAction(ACTION_DEMO);         context.registerReceiverAsUser(mDemoReceiver, UserHandle.ALL, demoFilter,                 android.Manifest.permission.DUMP, null);           // listen for USER_SETUP_COMPLETE setting (per-user)         resetUserSetupObserver();           // disable profiling bars, since they overlap and clutter the output on app windows         ThreadedRenderer.overrideProperty("disableProfileBars", "true");           // Private API call to make the shadows look better for Recents         ThreadedRenderer.overrideProperty("ambientRatio", String.valueOf(1.5f));         mStatusBarPlmnPlugin.addPlmn((LinearLayout)mStatusBarView.                                      findViewById(R.id.status_bar_contents), mContext);           return mStatusBarView;     }     ...

因为这块涉及的太广，所以接下来只分析StatusBar相关的一块，以导航栏为例进行讲解，我们重新回到PhoneStatusBar的start方法中，找到导航栏这块，发现它是调用addNavigationBar函数，所以我们查看这个函数：

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

class="hljs cs">class="hljs avrasm">    ...     // For small-screen devices (read: phones) that lack hardware navigation buttons     private void addNavigationBar() {         if (DEBUG) Log.v(TAG, "addNavigationBar: about to add " + mNavigationBarView);         //1.判断mNavigationBarView是否为空，这个视图有上面分析的makeStatusBarView方法中进行创建         if (mNavigationBarView == null) return;         //2.加载导航栏的具体显示（导航栏的显示由横向显示和竖向显示，后面分析）         prepareNavigationBarView();         //3.根据LayoutParams，加载导航栏到窗体中         mWindowManager.addView(mNavigationBarView, getNavigationBarLayoutParams());     }     ...         private void prepareNavigationBarView() {         mNavigationBarView.reorient();         //设置导航栏三个图标的点击事件         mNavigationBarView.getRecentsButton().setOnClickListener(mRecentsClickListener);         mNavigationBarView.getRecentsButton().setOnTouchListener(mRecentsPreloadOnTouchListener);         mNavigationBarView.getRecentsButton().setLongClickable(true);         mNavigationBarView.getRecentsButton().setOnLongClickListener(mLongPressBackRecentsListener);         mNavigationBarView.getBackButton().setLongClickable(true);         mNavigationBarView.getBackButton().setOnLongClickListener(mLongPressBackRecentsListener);         mNavigationBarView.getHomeButton().setOnTouchListener(mHomeActionListener);         mNavigationBarView.getHomeButton().setOnLongClickListener(mLongPressHomeListener);         mAssistManager.onConfigurationChanged();         /// M: add for multi window @{         if(MultiWindowProxy.isSupported()){             mNavigationBarView.getFloatButton().setOnClickListener(mFloatClickListener);             if(mIsSplitModeEnable){                 mNavigationBarView.getFloatModeButton().setOnClickListener(mFloatModeClickListener);                 mNavigationBarView.getSplitModeButton().setOnClickListener(mSplitModeClickListener);             }             MultiWindowProxy.getInstance().setSystemUiCallback(new MWSystemUiCallback());         }         /// @}     }

我们根据上面的注释来进行分析，主要内容有
1. 导航栏布局的创建
2. 导航栏布局分析及加载
3. 导航栏LayoutParams分析

导航栏布局的创建

在PhoneStatusBar的makeStatusBarView方法中，我们可以看到导航栏是怎么创建的

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48

class="hljs cs">class="hljs r">    ...     protected PhoneStatusBarView makeStatusBarView() {         ...         ...           try {             //是否显示导航栏             boolean showNav = mWindowManagerService.hasNavigationBar();              Log.v(TAG, "hasNavigationBar=" + showNav);             if (showNav) {                 /// M: add for multi window @{                 //加载导航栏布局                 int layoutId = R.layout.navigation_bar;                 //是否支持多窗口                 if(MultiWindowProxy.isSupported()) {                     layoutId = R.layout.navigation_bar_float_window;                 }                 mNavigationBarView = (NavigationBarView) View.inflate(context,                         /*R.layout.navigation_bar*/layoutId, null);                 /// @}                 mNavigationBarView.setDisabledFlags(mDisabled1);                 mNavigationBarView.setBar(this);                 mNavigationBarView.setOnVerticalChangedListener(                         new NavigationBarView.OnVerticalChangedListener() {                     @Override                     public void onVerticalChanged(boolean isVertical) {                         if (mAssistManager != null) {                             mAssistManager.onConfigurationChanged();                         }                         mNotificationPanel.setQsScrimEnabled(!isVertical);                     }                 });                 //设置导航栏触摸事件                 mNavigationBarView.setOnTouchListener(new View.OnTouchListener() {                     @Override                     public boolean onTouch(View v, MotionEvent event) {                         checkUserAutohide(v, event);                         return false;                     }});             }         } catch (RemoteException ex) {             // no window manager? good luck with that         }           ...         ...     }     ...

首先由mWindowManagerService的hasNavigationBar来决定是否显示导航栏，同时通过加载navigation_bar（多窗口加载navigation_bar_float_window）布局来显示导航栏，我们来查看hasNavigationBar方法，因为mWidnwoManagerService是IWindowManagerService由PhoneWindowManager进行调用：
frameworks\base\service\core\java\com\android\server\PhoneWindowManager.java

PhoneWindowManager

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

class="hljs cs">class="hljs r">    ...     // Use this instead of checking config_showNavigationBar so that it can be consistently     // overridden by qemu.hw.mainkeys in the emulator.     @Override     public boolean hasNavigationBar() {         return mHasNavigationBar;     }     ...     mHasNavigationBar = res.getBoolean(com.android.internal.R.bool.config_showNavigationBar);     // Allow a system property to override this. Used by the emulator.     // See also hasNavigationBar().     String navBarOverride = SystemProperties.get("qemu.hw.mainkeys");     if ("1".equals(navBarOverride)) {          mHasNavigationBar = false;      } else if ("0".equals(navBarOverride)) {          mHasNavigationBar = true;     }     ...

从framework\base\core\res\res\valuse\config.xml中获取mHashNavigationBar的值

?

1 2 3

class="hljs cs">class="hljs xml">        "config_showNavigationBar">ture

然后从系统配置位置中取qemu.hw.mainkeys的值，所以这里给我们提供了一个隐藏状态栏的新思路，除了在createAndAddWindows中注释掉addNavigationBar函数外，我们也可以通过修改framework下的config.xml的config_showNavigationBar的值和修改系统配置文件的值来达到隐藏状态栏的目的

导航栏布局分析及加载

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

...         private void prepareNavigationBarView() {         mNavigationBarView.reorient();         //设置导航栏三个图标的点击事件         mNavigationBarView.getRecentsButton().setOnClickListener(mRecentsClickListener);         mNavigationBarView.getRecentsButton().setOnTouchListener(mRecentsPreloadOnTouchListener);         mNavigationBarView.getRecentsButton().setLongClickable(true);         mNavigationBarView.getRecentsButton().setOnLongClickListener(mLongPressBackRecentsListener);         mNavigationBarView.getBackButton().setLongClickable(true);         mNavigationBarView.getBackButton().setOnLongClickListener(mLongPressBackRecentsListener);         mNavigationBarView.getHomeButton().setOnTouchListener(mHomeActionListener);         mNavigationBarView.getHomeButton().setOnLongClickListener(mLongPressHomeListener);         mAssistManager.onConfigurationChanged();         /// M: add for multi window @{         if(MultiWindowProxy.isSupported()){             mNavigationBarView.getFloatButton().setOnClickListener(mFloatClickListener);             if(mIsSplitModeEnable){                 mNavigationBarView.getFloatModeButton().setOnClickListener(mFloatModeClickListener);                 mNavigationBarView.getSplitModeButton().setOnClickListener(mSplitModeClickListener);             }             MultiWindowProxy.getInstance().setSystemUiCallback(new MWSystemUiCallback());         }         /// @}     }     ...

导航栏布局的确切显示在prepareNavigationBarView中的mNavigationBarView.reorient();来决定，我们查看reorient方法

reorient

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

class="hljs cs">class="hljs r">    ...     public void reorient() {         //获取屏幕方向         final int rot = mDisplay.getRotation();         //隐藏导航栏布局         for (int i=0; i<4; i++) {             mRotatedViews[i].setVisibility(View.GONE);         }         //根据屏幕方向显示导航栏布局         mCurrentView = mRotatedViews[rot];         mCurrentView.setVisibility(View.VISIBLE);         setLayoutTransitionsEnabled(mLayoutTransitionsEnabled);           getImeSwitchButton().setOnClickListener(mImeSwitcherClickListener);           mDeadZone = (DeadZone) mCurrentView.findViewById(R.id.deadzone);           // force the low profile & disabled states into compliance         mBarTransitions.init();         setDisabledFlags(mDisabledFlags, true /* force */);         setMenuVisibility(mShowMenu, true /* force */);           if (DEBUG) {             Log.d(TAG, "reorient(): rot=" + mDisplay.getRotation());         }           updateTaskSwitchHelper();           setNavigationIconHints(mNavigationIconHints, true);     }     ...

导航栏的显示由屏幕的方向来决定，而导航栏有两种不同的显示方式，横向显示和竖向显示，我们可以从mRotatedViews进行追查到

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

...     View[] mRotatedViews = new View[4];     ...     @Override     public void onFinishInflate() {         //屏幕方位0和180方向显示的导航栏为rot0         mRotatedViews[Surface.ROTATION_0] =         mRotatedViews[Surface.ROTATION_180] = findViewById(R.id.rot0);         //屏幕访问90和270显示的导航栏为rot90         mRotatedViews[Surface.ROTATION_90] = findViewById(R.id.rot90);           mRotatedViews[Surface.ROTATION_270] = mRotatedViews[Surface.ROTATION_90];           //mCurrentView = mRotatedViews[Surface.ROTATION_0];         mCurrentView = mRotatedViews[Surface.ROTATION_90];         getImeSwitchButton().setOnClickListener(mImeSwitcherClickListener);           updateRTLOrder();     }     ...

布局加载完成后，会回调onFinishInflate方法，在这方法中对屏幕的几个方向初始化4个导航栏view，其中0和180为横向布局，90和270为纵向布局，我们可以从导航栏（NavigationBarView）布局文件中可以看出
res\layout\navigation_bar.xml和res\layout\navigation_bar

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68

class="hljs cs">class="hljs xml">"@drawable/system_bar_background" android:layout_height="match_parent" android:layout_width="match_parent" xmlns:android="https://schemas.android.com/apk/res/android" xmlns:systemui="https://schemas.android.com/apk/res-auto">          "@+id/rot0" android:layout_height="match_parent" android:layout_width="match_parent">           "true" android:clipchildren="false" android:cliptopadding="false" android:id="@+id/nav_buttons" android:layout_height="match_parent" android:layout_width="match_parent" android:orientation="horizontal">                            "match_parent" android:layout_weight="0" android:layout_width="@dimen/navigation_side_padding" android:visibility="invisible">                          "@string/accessibility_back" android:id="@+id/back" android:layout_height="match_parent" android:layout_weight="0" android:layout_width="@dimen/navigation_key_width" android:scaletype="center" android:src="@drawable/ic_sysbar_back" systemui:keycode="4">             "match_parent" android:layout_weight="1" android:layout_width="0dp" android:visibility="invisible">                          "@string/accessibility_home" android:id="@+id/home" android:layout_height="match_parent" android:layout_weight="0" android:layout_width="@dimen/navigation_key_width" android:scaletype="center" android:src="@drawable/ic_sysbar_home" systemui:keycode="3" systemui:keyrepeat="false">             "match_parent" android:layout_weight="1" android:layout_width="0dp" android:visibility="invisible">                          "@string/accessibility_recent" android:id="@+id/recent_apps" android:layout_height="match_parent" android:layout_weight="0" android:layout_width="@dimen/navigation_key_width" android:scaletype="center" android:src="@drawable/ic_sysbar_recent">             "match_parent" android:layout_weight="0" android:layout_width="@dimen/navigation_side_padding">                 "@string/accessibility_menu" android:id="@+id/menu" android:layout_gravity="end" android:layout_height="match_parent" android:layout_width="@dimen/navigation_extra_key_width" android:scaletype="centerInside" android:src="@drawable/ic_sysbar_menu" android:visibility="invisible" systemui:keycode="82">                   "@string/accessibility_ime_switch_button" android:id="@+id/ime_switcher" android:layout_gravity="end" android:layout_height="match_parent" android:layout_width="@dimen/navigation_extra_key_width" android:scaletype="centerInside" android:src="@drawable/ic_ime_switcher_default" android:visibility="invisible">                                            "@+id/lights_out" android:layout_height="match_parent" android:layout_width="match_parent" android:orientation="horizontal" android:visibility="gone">             "@string/accessibility_back" android:layout_height="match_parent" android:layout_marginstart="@dimen/navigation_side_padding" android:layout_weight="0" android:layout_width="@dimen/navigation_key_width" android:scaletype="center" android:src="@drawable/ic_sysbar_lights_out_dot_small">             "match_parent" android:layout_weight="1" android:layout_width="match_parent" android:visibility="invisible">             "@string/accessibility_home" android:layout_height="match_parent" android:layout_weight="0" android:layout_width="@dimen/navigation_key_width" android:scaletype="center" android:src="@drawable/ic_sysbar_lights_out_dot_large">             "match_parent" android:layout_weight="1" android:layout_width="match_parent" android:visibility="invisible">             "@string/accessibility_recent" android:layout_height="match_parent" android:layout_marginend="@dimen/navigation_side_padding" android:layout_weight="0" android:layout_width="@dimen/navigation_key_width" android:scaletype="center" android:src="@drawable/ic_sysbar_lights_out_dot_small">                    "@+id/deadzone" android:layout_gravity="top" android:layout_height="match_parent" android:layout_width="match_parent" systemui:decaytime="@integer/navigation_bar_deadzone_decay" systemui:holdtime="@integer/navigation_bar_deadzone_hold" systemui:maxsize="@dimen/navigation_bar_deadzone_size_max" systemui:minsize="@dimen/navigation_bar_deadzone_size" systemui:orientation="horizontal">               "@+id/rot90" android:layout_height="match_parent" android:layout_width="match_parent" android:paddingtop="0dp" android:visibility="gone">           "true" android:clipchildren="false" android:cliptopadding="false" android:id="@+id/nav_buttons" android:layout_height="match_parent" android:layout_width="match_parent" android:orientation="vertical">                            "@dimen/navigation_side_padding" android:layout_weight="0" android:layout_width="match_parent">                 "@string/accessibility_ime_switch_button" android:id="@+id/ime_switcher" android:layout_gravity="top" android:layout_height="@dimen/navigation_extra_key_width" android:layout_width="match_parent" android:scaletype="centerInside" android:src="@drawable/ic_ime_switcher_default" android:visibility="invisible">                   "@string/accessibility_menu" android:id="@+id/menu" android:layout_gravity="top" android:layout_height="40dp" android:layout_width="match_parent" android:scaletype="centerInside" android:src="@drawable/ic_sysbar_menu_land" android:visibility="invisible" systemui:keycode="82">                            "@string/accessibility_recent" android:id="@+id/recent_apps" android:layout_height="@dimen/navigation_key_width" android:layout_weight="0" android:layout_width="match_parent" android:scaletype="center" android:src="@drawable/ic_sysbar_recent_land">             "match_parent" android:layout_weight="1" android:layout_width="match_parent" android:visibility="invisible">             "@string/accessibility_home" android:id="@+id/home" android:layout_height="@dimen/navigation_key_width" android:layout_weight="0" android:layout_width="match_parent" android:scaletype="center" android:src="@drawable/ic_sysbar_home_land" systemui:keycode="3" systemui:keyrepeat="false">             "match_parent" android:layout_weight="1" android:layout_width="match_parent" android:visibility="invisible">             "@string/accessibility_back" android:id="@+id/back" android:layout_height="@dimen/navigation_key_width" android:layout_weight="0" android:layout_width="match_parent" android:scaletype="center" android:src="@drawable/ic_sysbar_back_land" systemui:keycode="4">             "@dimen/navigation_side_padding" android:layout_weight="0" android:layout_width="match_parent" android:visibility="invisible">                             "@+id/lights_out" android:layout_height="match_parent" android:layout_width="match_parent" android:orientation="vertical" android:visibility="gone">             "@string/accessibility_recent" android:layout_height="@dimen/navigation_key_width" android:layout_margintop="@dimen/navigation_side_padding" android:layout_weight="0" android:layout_width="match_parent" android:scaletype="center" android:src="@drawable/ic_sysbar_lights_out_dot_small">             "match_parent" android:layout_weight="1" android:layout_width="match_parent" android:visibility="invisible">             "@string/accessibility_home" android:layout_height="@dimen/navigation_key_width" android:layout_weight="0" android:layout_width="match_parent" android:scaletype="center" android:src="@drawable/ic_sysbar_lights_out_dot_large">             "match_parent" android:layout_weight="1" android:layout_width="match_parent" android:visibility="invisible">             "@string/accessibility_back" android:layout_height="@dimen/navigation_key_width" android:layout_marginbottom="@dimen/navigation_side_padding" android:layout_weight="0" android:layout_width="match_parent" android:scaletype="center" android:src="@drawable/ic_sysbar_lights_out_dot_small">                    "@+id/deadzone" android:layout_gravity="top" android:layout_height="match_parent" android:layout_width="match_parent" systemui:decaytime="@integer/navigation_bar_deadzone_decay" systemui:holdtime="@integer/navigation_bar_deadzone_hold" systemui:maxsize="@dimen/navigation_bar_deadzone_size_max" systemui:minsize="@dimen/navigation_bar_deadzone_size" systemui:orientation="vertical">

所以说，当我们的需求为0或者90度方向，要想导航栏纵向显示，我们只需要修改成导航栏纵向布局即可，当然我们也可以按需求来隐藏某些导航栏按键（布局中设置某些控件为gone）

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

@Override     public void onFinishInflate() {         mRotatedViews[Surface.ROTATION_0] =         mRotatedViews[Surface.ROTATION_180] = findViewById(R.id.rot0);           mRotatedViews[Surface.ROTATION_90] = findViewById(R.id.rot90);           mRotatedViews[Surface.ROTATION_270] = mRotatedViews[Surface.ROTATION_90];           //mCurrentView = mRotatedViews[Surface.ROTATION_0];         //显示纵向的导航栏         mCurrentView = mRotatedViews[Surface.ROTATION_90];         getImeSwitchButton().setOnClickListener(mImeSwitcherClickListener);           updateRTLOrder();     }

导航栏LayoutParams分析

我们回到PhoneStatusBar的addNavigationBar继续分析最后一个导航栏的LayoutParameters，它决定了导航栏在窗体上的显示位置

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

class="hljs cs">class="hljs avrasm">    private WindowManager.LayoutParams getNavigationBarLayoutParams() {         //充满父布局         WindowManager.LayoutParams lp = new WindowManager.LayoutParams(                 LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT,                 WindowManager.LayoutParams.TYPE_NAVIGATION_BAR,//导航栏                     0                     | WindowManager.LayoutParams.FLAG_TOUCHABLE_WHEN_WAKING//当手机处于睡眠状态时，如果屏幕被按下，那么该window将第一个收到到事件                     | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE//不获取焦点                     | WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL//即使在该window在可获得焦点情况下，仍然把该window之外的任何event发送到该window之后的其他window                     | WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH//不接受事件，转发到其他window                     | WindowManager.LayoutParams.FLAG_SPLIT_TOUCH,//当该window在可以接受触摸屏情况下，让因在该window之外，而发送到后面的window的触摸屏可以支持split touch.                 PixelFormat.TRANSLUCENT);         // this will allow the navbar to run in an overlay on devices that support this         if (ActivityManager.isHighEndGfx()) {             lp.flags |= WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED;//硬件加速         }         //lp.gravity = Gravity.RIGHT;         lp.setTitle("NavigationBar");         lp.windowAnimations = 0;         return lp;     }

上面的LayoutParames决定了导航栏在窗体的大小（受父布局影响）和显示的位置效果，当我们的需求如果要把导航栏显示在屏幕的右边时，我们可以在上面代码中加上下面一句

 

1  lp.gravity = Gravity.RIGHT;

SystemUI包含了太多内容，本篇只是分析了SystemUI的加载流程，同时初步的分析了StatusBar中一个小模块NavigationBar，后续会针对SystemUI的其他模块进行分析。