Android 7.0 SystemUI 之启动和状态栏和导航栏简介

Android 7.0 SystemUI 之启动和状态栏和导航栏简介

一、SystemUI 是什么

首先SystemUI 是一个系统应用,apk路径位于/system/priv-app

源码路径位于:/framework/base/packages/SystemUI

它负责的功能如下:

• 状态栏信息的展示:比如电量信息，时间，wifi状态等
• 通知栏消息
• 壁纸管理
• 截图功能
• 近期任务栏显示,比如长按home键显示最近使用的app
• 录制屏幕功能
• 截图服务

以下是7.0 SystemUI 的代码截图

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二、SystemUI 的启动

SystemUI 是在SystemServer里的AMS实例的systemReady方法里调用startSystemUi方法启动

SystemServer路径:/base/services/java/com/android/server/SystemServer.java

 mActivityManagerService.systemReady(new Runnable() { ...... static final void startSystemUi(Context context) {        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);    } ......
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在这个方法里启动一个SystemUIService服务.

public class SystemUIService extends Service {    @Override    public void onCreate() {        super.onCreate();        ((SystemUIApplication) getApplication()).startServicesIfNeeded();    }    ......
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在onCreate方法中会调用SystemUIApplication的startServicesIfNeeded方法，这个方法会调用 startServicesIfNeeded(SERVICES)方法启动一系列服务(并不是真正的服务,都继承自SystemUI),可以这么说SystemUI就是一个容器,里面装有负责不同功能的模块。

public class SystemUIApplication extends Application {    ......    private final Class<?>[] SERVICES = new Class[] {            com.android.systemui.tuner.TunerService.class,            com.android.systemui.keyguard.KeyguardViewMediator.class,            com.android.systemui.recents.Recents.class,            com.android.systemui.volume.VolumeUI.class,            Divider.class,            com.android.systemui.statusbar.SystemBars.class,            com.android.systemui.usb.StorageNotification.class,            com.android.systemui.power.PowerUI.class,            com.android.systemui.media.RingtonePlayer.class,            com.android.systemui.keyboard.KeyboardUI.class,            com.android.systemui.tv.pip.PipUI.class,            com.android.systemui.shortcut.ShortcutKeyDispatcher.class    };public void startServicesIfNeeded() {        startServicesIfNeeded(SERVICES);    }    ......
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startServicesIfNeeded方法会遍历services这个数组,依次调用service的start方法启动服务

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private void startServicesIfNeeded(Class<?>[] services) {        //如果已经启动了就返回        if (mServicesStarted) {            return;        }        //如果没启动完成完成        if (!mBootCompleted) {            if ("1".equals(SystemProperties.get("sys.boot_completed"))) {                mBootCompleted = true;                if (DEBUG) Log.v(TAG, "BOOT_COMPLETED was already sent");            }        }        final int N = services.length;        for (int i=0; i<N; i++) {            Class<?> cl = services[i];            if (DEBUG) Log.d(TAG, "loading: " + cl);            try {                Object newService = SystemUIFactory.getInstance().createInstance(cl);                mServices[i] = (SystemUI) ((newService == null) ? cl.newInstance() : newService);            } catch (IllegalAccessException ex) {                throw new RuntimeException(ex);            } catch (InstantiationException ex) {                throw new RuntimeException(ex);            }            //启动服务                  mServices[i].start();            //如果启动完成了            if (mBootCompleted) {                mServices[i].onBootCompleted();            }        }        mServicesStarted = true;    }
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---

这里以com.android.systemui.statusbar.SystemBars.class为例,讲解一下

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三、状态栏和导航栏 的启动

SystemBars的start方法会创建一个ServiceMonitor(服务监听者),会进入到ServiceMonitor的start方法

 public class SystemBars extends SystemUI implements ServiceMonitor.Callbacks { ...... public void start() {        //  ServiceMonitor是服务监听者        mServiceMonitor = new ServiceMonitor(TAG, DEBUG, mContext, Settings.Secure.BAR_SERVICE_COMPONENT, this);        mServiceMonitor.start();  // will call onNoService if no remote service is found    } ......    }   
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在ServiceMonitor的start方法启动

  public class ServiceMonitor {  ......      public void start() {        ......        mHandler.sendEmptyMessage(MSG_START_SERVICE);    }  ......        }
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在Handler里处理这个MSG_START_SERVICE

  public class ServiceMonitor {  ......      private final Handler mHandler = new Handler() {        public void handleMessage(Message msg) {            switch(msg.what) {                case MSG_START_SERVICE:                    //启动服务                    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;            }        }    };    ......    }
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startService方法如下

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 public class ServiceMonitor {  ......     private void startService() {    //获取服务组件名称    mServiceName = getComponentNameFromSetting();    //如果为空，回调服务的onNoService方法    if (mServiceName == null) {            mBound = false;            mCallbacks.onNoService();        } else {        //不为空,回调服务的的onServiceStartAttempt方法            long delay = mCallbacks.onServiceStartAttempt();            mHandler.sendEmptyMessageDelayed(MSG_CONTINUE_START_SERVICE, delay);        }    }    ......    }
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这里对mServiceName是否为空进行判断，总之无论如何它最终都会启动这个服务。

回调SystemBars的onNoService里创建StatusBar

   public class SystemBars extends SystemUI implements ServiceMonitor.Callbacks {   ...... @Override    public void onNoService() {    if (DEBUG) Log.d(TAG, "onNoService");    //创建StatusBar    createStatusBarFromConfig();  // fallback to using an in-process implementation    }   ......
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  private void createStatusBarFromConfig() {        //config_statusBarComponent就是PhoneStatusBar        final String clsName = mContext.getString(R.string.config_statusBarComponent);        Class<?> cls = null;        try {            cls = mContext.getClassLoader().loadClass(clsName);        } catch (Throwable t) {            throw andLog("Error loading status bar component: " + clsName, t);        }        try {            //创建BaseStatusBar实例            mStatusBar = (BaseStatusBar) cls.newInstance();        } catch (Throwable t) {            throw andLog("Error creating status bar component: " + clsName, t);        }        mStatusBar.mContext = mContext;        mStatusBar.mComponents = mComponents;        //启动        mStatusBar.start();    }
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在createStatusBarFromConfig方法里会获取一个config_statusBarComponent的字符串值，这个值就是PhoneStatusBar的clasName

所以这里的mStatusBar是PhoneStatusBar实例,启动了PhoneStatusBar

PhoneStatusBar的start方法

public class PhoneStatusBar extends BaseStatusBar implements DemoMode, DragDownHelper.DragDownCallback, ActivityStarter, OnUnlockMethodChangedListener,HeadsUpManager.OnHeadsUpChangedListener {        ......        public void start() {         ......        //调用父类的start方法,在父类BaseStatusBar里调用createAndAddWindows方法        // 3.1        super.start(); // calls createAndAddWindows()         ......        //添加导航栏        // 3.2        addNavigationBar();        ......    }
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它会回调父类BaseStatusBar 的start方法

3.1、 super.start()

public abstract class BaseStatusBar extends SystemUI implements        CommandQueue.Callbacks, ActivatableNotificationView.OnActivatedListener,        ExpandableNotificationRow.ExpansionLogger, NotificationData.Environment,        ExpandableNotificationRow.OnExpandClickListener,        OnGutsClosedListener {      ......    public void start() {    ......    /*实例化IStatusBarService,    随后BaseStatusBar将自己注册到IStatusBarService之中。以此声明本实例才是状态栏的真正        实现者，IStatusBarService会将其所接受到的请求转发给本实例。    IStatusBarService会保存SystemUi的状态信息,避免SystemUi崩溃而造成信息的丢失    */        mBarService = IStatusBarService.Stub.asInterface(                ServiceManager.getService(Context.STATUS_BAR_SERVICE));        ......        //IStatusBarService与BaseStatusBar进行通信的桥梁。        mCommandQueue = new CommandQueue(this);     /*switches则存储了一些杂项：禁用功能列表，SystemUIVisiblity，是否在导航栏中显示虚拟的        菜单键，输入法窗口是否可见、输入法窗口是否消费BACK键、是否接入了实体键盘、实体键盘是否被启用。        */        int[] switches = new int[9];        ArrayList<IBinder> binders = new ArrayList<IBinder>();        /*它保存了用于显示在状态栏的系统状态        区中的状态图标列表。在完成注册之后，IStatusBarService将会在其中填充两个数组，一个字符串        数组用于表示状态的名称，一个StatusBarIcon类型的数组用于存储需要显示的图标资源。        */        ArrayList<String> iconSlots = new ArrayList<>();        ArrayList<StatusBarIcon> icons = new ArrayList<>();        Rect fullscreenStackBounds = new Rect();        Rect dockedStackBounds = new Rect();    //IStatusBarService注册一些信息    try {            mBarService.registerStatusBar(mCommandQueue, iconSlots, icons, switches, binders,                    fullscreenStackBounds, dockedStackBounds);        } catch (RemoteException ex) {        }        //创建状态栏窗口        createAndAddWindows();        ......        }    ......    }
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BaseStatusBar进行一些设置,获取了IStatusBarService实例并注册一些信息到IStatusBarService中,IStatusBarService是一个系统服务,BaseStatusBar将自己注册到IStatusBarService之中,IStatusBarService会把操作状态栏和导航栏的请求转发给BaseStatusBar

为了保证SystemUI意外退出后不会发生信息丢失，IStatusBarService保存了所有需要状态栏与导航栏进行显示或处理的信息副本。 在注册时将一个继承自IStatusBar.Stub的CommandQueue的实例注册到IStatusBarService以建立通信，并将信息副本取回。

 public class CommandQueue extends IStatusBar.Stub {
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IStatusBarService的真身是StatusBarManagerService

路径:./services/core/java/com/android/server/statusbar/StatusBarManagerService.java

它的注册方法做一些数据的初始化

public class StatusBarManagerService extends IStatusBarService.Stub {     ...... public void registerStatusBar(IStatusBar bar, List<String> iconSlots,            List<StatusBarIcon> iconList, int switches[], List<IBinder> binders,            Rect fullscreenStackBounds, Rect dockedStackBounds) {        //检查权限           enforceStatusBarService();        mBar = bar;        synchronized (mIcons) {            for (String slot : mIcons.keySet()) {                iconSlots.add(slot);                iconList.add(mIcons.get(slot));            }        }        synchronized (mLock) {            switches[0] = gatherDisableActionsLocked(mCurrentUserId, 1);            switches[1] = mSystemUiVisibility;            switches[2] = mMenuVisible ? 1 : 0;            switches[3] = mImeWindowVis;            switches[4] = mImeBackDisposition;            switches[5] = mShowImeSwitcher ? 1 : 0;            switches[6] = gatherDisableActionsLocked(mCurrentUserId, 2);            switches[7] = mFullscreenStackSysUiVisibility;            switches[8] = mDockedStackSysUiVisibility;            binders.add(mImeToken);            fullscreenStackBounds.set(mFullscreenStackBounds);            dockedStackBounds.set(mDockedStackBounds);        }    }    ......    }
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这几者的关系如下

 
回到PhoneStatusBar中, 父类BaseStatusBar中的createAndAddWindows为抽象方法,由子类实现,看下PhoneStatusBar的 
createAndAddWindows

  @Override    public void createAndAddWindows() {        //添加状态栏窗口        addStatusBarWindow();    }
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方法实现如下

  private void addStatusBarWindow() {    //创建控件          makeStatusBarView();    //创建StatusBarWindowManager实例            mStatusBarWindowManager = new StatusBarWindowManager(mContext);    //创建远程输入控制实例            mRemoteInputController = new RemoteInputController(mStatusBarWindowManager,                mHeadsUpManager);    //添加状态栏窗口           mStatusBarWindowManager.add(mStatusBarWindow, getStatusBarHeight());    }
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看下makeStatusBarView方法

makeStatusBarView的方法里调用 inflateStatusBarWindow(context)加载布局

 protected void inflateStatusBarWindow(Context context) {        mStatusBarWindow = (StatusBarWindowView) View.inflate(context, R.layout.super_status_bar, null);    }
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这里介绍下布局

状态栏布局介绍

整个状态栏的父布局是R.layout.super_status_bar,对应的是StatusBarWindowView这个自定义布局.

<com.android.systemui.statusbar.phone.StatusBarWindowView    xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:sysui="http://schemas.android.com/apk/res-auto"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:fitsSystemWindows="true">    ......    <!--正常状态栏下的布局 -->    <include layout="@layout/status_bar"        android:layout_width="match_parent"        android:layout_height="@dimen/status_bar_height" />    <!--状态栏图标下的SeekBar布局 -->    <include layout="@layout/brightness_mirror" />    <!--车载模式的布局  -->    <ViewStub android:id="@+id/fullscreen_user_switcher_stub"              android:layout="@layout/car_fullscreen_user_switcher"              android:layout_width="match_parent"              android:layout_height="match_parent"/>    <!--状态栏下拉的布局  -->    <include layout="@layout/status_bar_expanded"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:visibility="gone" /></com.android.systemui.statusbar.phone.StatusBarWindowView>
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---

我这里以主要的布局层次做介绍,结合图片分析会更加清楚

StatusBarWindowView里有几个主要的布局

• layout/status_bar
• layout/brightness_mirror
• layout/status_bar_expanded

如下图 

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1.layout/status_bar

这个是正常状态下(未下拉的状态栏图标区域)

这个布局对应的是PhoneStatusBarView

<com.android.systemui.statusbar.phone.PhoneStatusBarView    xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:systemui="http://schemas.android.com/apk/res/com.android.systemui"    android:id="@+id/status_bar"    android:background="@drawable/system_bar_background"    android:orientation="vertical"    android:focusable="false"    android:descendantFocusability="afterDescendants"    >    ......    <!--状态栏  -->    <LinearLayout android:id="@+id/status_bar_contents"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:paddingStart="6dp"        android:paddingEnd="8dp"        android:orientation="horizontal"        >        <!-- The alpha of this area is controlled from both PhoneStatusBarTransitions and             PhoneStatusBar (DISABLE_NOTIFICATION_ICONS). -->        <!-- 通知图标区域-->        <com.android.systemui.statusbar.AlphaOptimizedFrameLayout            android:id="@+id/notification_icon_area"            android:layout_width="0dip"            android:layout_height="match_parent"            android:layout_weight="1"            android:orientation="horizontal" />        <!-- 系统图标区域 -->        <com.android.keyguard.AlphaOptimizedLinearLayout android:id="@+id/system_icon_area"            android:layout_width="wrap_content"            android:layout_height="match_parent"            android:orientation="horizontal"            >            <!-- 系统图标 -->            <include layout="@layout/system_icons" />            <!-- 时钟信息 -->            <com.android.systemui.statusbar.policy.Clock                android:id="@+id/clock"                android:textAppearance="@style/TextAppearance.StatusBar.Clock"                android:layout_width="wrap_content"                android:layout_height="match_parent"                android:singleLine="true"                android:paddingStart="@dimen/status_bar_clock_starting_padding"                android:paddingEnd="@dimen/status_bar_clock_end_padding"                android:gravity="center_vertical|start"                />        </com.android.keyguard.AlphaOptimizedLinearLayout>    </LinearLayout></com.android.systemui.statusbar.phone.PhoneStatusBarView>
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---

以下是细节图,连线表示层次结构

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其中,状态栏的区域分为以下几种

• 通知栏图标,在状态栏的最左侧显示通知信息,比如来了一个短信,那么就会弹出一个短信图标
• 时间信息,显示一个时间,比如上午9:58
• 信号图标,显示手机信号,wifi信号等
• 电量图标,显示当前电量状态
• 状态图标,wifi,蓝牙等开关状态

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2.@layout/brightness_mirror

这个布局就是中间那个调整亮度的seekBar.没啥好介绍的.

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3.@layout/status_bar_expanded

这个布局是下拉时的状态栏的布局

<com.android.systemui.statusbar.phone.NotificationPanelView     xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:systemui="http://schemas.android.com/apk/res/com.android.systemui"    android:id="@+id/notification_panel"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:background="@android:color/transparent"    >    <!--锁屏时的时钟布局  -->    <include        layout="@layout/keyguard_status_view"        android:layout_height="wrap_content"        android:visibility="gone" />    <com.android.systemui.statusbar.phone.NotificationsQuickSettingsContainer        android:layout_width="match_parent"        android:layout_height="match_parent"        android:layout_gravity="@integer/notification_panel_layout_gravity"        android:id="@+id/notification_container_parent"        android:clipToPadding="false"        android:clipChildren="false">        <!--quciksetting区域  -->        <com.android.systemui.AutoReinflateContainer            android:id="@+id/qs_auto_reinflate_container"            android:layout="@layout/qs_panel"            android:layout_width="@dimen/notification_panel_width"            android:layout_height="match_parent"            android:layout_gravity="@integer/notification_panel_layout_gravity"            android:clipToPadding="false"            android:clipChildren="false" />        <!-- 通知栏区域 -->        <com.android.systemui.statusbar.stack.NotificationStackScrollLayout            android:id="@+id/notification_stack_scroller"            android:layout_width="@dimen/notification_panel_width"            android:layout_height="match_parent"            android:layout_gravity="@integer/notification_panel_layout_gravity"            android:layout_marginBottom="@dimen/close_handle_underlap" />        <!--锁屏切换 -->        <ViewStub            android:id="@+id/keyguard_user_switcher"            android:layout="@layout/keyguard_user_switcher"            android:layout_height="match_parent"            android:layout_width="match_parent" />        <!--锁屏下的状态栏 -->        <include            layout="@layout/keyguard_status_bar"            android:visibility="invisible" />    </com.android.systemui.statusbar.phone.NotificationsQuickSettingsContainer>    <!--锁屏界面底部的图标 -->    <include            layout="@layout/keyguard_bottom_area"            android:visibility="gone" /></com.android.systemui.statusbar.phone.NotificationPanelView><!-- end of sliding panel -->
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---

细节图

---

---

创建完布局后，就会添加窗口到WindowManager里,这样状态栏就创建完成了.接下来会回到3.2 addNavigationBar()的步骤中.

3.2、addNavigationBar

这个方法是添加底部的导航栏的,就是那些home键,back键所在的区域.

public class PhoneStatusBar extends BaseStatusBar implements DemoMode, DragDownHelper.DragDownCallback, ActivityStarter, OnUnlockMethodChangedListener,HeadsUpManager.OnHeadsUpChangedListener {    ......    protected void addNavigationBar() {        if (mNavigationBarView == null) return;        //初始化导航栏        prepareNavigationBarView();        //添加到WindowManager中        mWindowManager.addView(mNavigationBarView, getNavigationBarLayoutParams());    }    ......    }
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在这个方法里先初始化导航栏,然后把导航栏添加到窗口中.

prepareNavigationBarView()

public class PhoneStatusBar extends BaseStatusBar implements DemoMode, DragDownHelper.DragDownCallback, ActivityStarter, OnUnlockMethodChangedListener,HeadsUpManager.OnHeadsUpChangedListener {        ...... private void prepareNavigationBarView() {        //重新初始化         mNavigationBarView.reorient();        //最近应用键        ButtonDispatcher recentsButton = mNavigationBarView.getRecentsButton();        recentsButton.setOnClickListener(mRecentsClickListener);        recentsButton.setOnTouchListener(mRecentsPreloadOnTouchListener);        recentsButton.setLongClickable(true);        recentsButton.setOnLongClickListener(mRecentsLongClickListener);        //后退键        ButtonDispatcher backButton = mNavigationBarView.getBackButton();        backButton.setLongClickable(true);        backButton.setOnLongClickListener(mLongPressBackListener);        //home键        ButtonDispatcher homeButton = mNavigationBarView.getHomeButton();        homeButton.setOnTouchListener(mHomeActionListener);        homeButton.setOnLongClickListener(mLongPressHomeListener);        //监听配置改变        mAssistManager.onConfigurationChanged();        }        ......    }
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四、结束

关于SystemUI的状态栏和导航栏就介绍完了，讲的很浅显，只是从整体上梳理了下流程.

原文地址：　http://blog.csdn.net/qq_31530015/article/details/53507968