Android SystemUI分析

原创文章，转载请注明出处：http://blog.csdn.net/ruils/article/details/17324397

SystemUI即Android系统的UI界面。手机厂商需要深度定制Android系统的UI界面就需要修改这里面的东西，比如双卡手机，就需要在状态栏增加手机状态图标。

SystemUI包括:

StatusBar,  状态栏，最上面那一排

NavigationBar, 导航栏，最下面那一排虚拟键，有Back键，Home键，Recents键（最近使用程序列表键）

Recent APP List，最近使用程序列表界面

Wallpaper, 壁纸

USB相关界面

其他等。

SystemUI所在目录为frameworks/base/packages/SystemUI,从Android4.0以后的版本，SystemUI编译都会生成SystemUI.apk。

SystemUI在SystemServer中被启动：

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

     if (!headless) startSystemUi(contextF); 

startSystemUi方法：

    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);
     }

启动SyseUIService

frameworks/base/packages/SystemUI/src/com/android/systemui/SystemUIService.java

SystemUIService的Oncreate方法：

 @Override
    public void onCreate() {
        // Tell the accessibility layer that this process will
        // run as the current user, i.e. run across users.
        AccessibilityManager.createAsSharedAcrossUsers(this);

        // Pick status bar or system bar.
        IWindowManager wm = WindowManagerGlobal.getWindowManagerService();
        try {
            SERVICES[0] = wm.hasSystemNavBar()
                    ? R.string.config_systemBarComponent
                    : R.string.config_statusBarComponent;
        } catch (RemoteException e) {
            Slog.w(TAG, "Failing checking whether status bar can hide", e); 
        }   

        final int N = SERVICES.length;
        mServices = new SystemUI[N];
        for (int i=0; i

分别调用SERVICES里的类的start方法：

 final Object[] SERVICES = new Object[] {
            0, // system bar or status bar, filled in below.
            com.android.systemui.power.PowerUI.class,
            com.android.systemui.media.RingtonePlayer.class,
            com.android.systemui.settings.SettingsUI.class,
        };

这个0从SystemUIService的onCreate方法中可以看到，会被config_systemBarComponent或者config_statusBarComponent替换掉。

// Pick status bar or system bar.
        IWindowManager wm = WindowManagerGlobal.getWindowManagerService();
        try {
            SERVICES[0] = wm.hasSystemNavBar()
                    ? R.string.config_systemBarComponent
                    : R.string.config_statusBarComponent;
        } catch (RemoteException e) {
            Slog.w(TAG, "Failing checking whether status bar can hide", e);
        }

frameworks/base/packages/SystemUI/res/values/config.xml

 
    com.android.systemui.statusbar.phone.PhoneStatusBar

    
    com.android.systemui.statusbar.tablet.TabletStatusBar

这里一个是手机的StatusBar一个是平板的StatusBar。

我们看手机的StatusBar,

frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java

PhoneStatusBar的start()方法：

   @Override
    public void start() {
        mDisplay = ((WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE))
                .getDefaultDisplay();

        mDreamManager = IDreamManager.Stub.asInterface(
                ServiceManager.checkService(DreamService.DREAM_SERVICE));

        super.start(); // calls createAndAddWindows()

        addNavigationBar();

        if (ENABLE_INTRUDERS) addIntruderView();

        // Lastly, call to the icon policy to install/update all the icons.
        mIconPolicy = new PhoneStatusBarPolicy(mContext);
    }

这里主要做了三件事：

1.将StatusBar添加到WindowManager中

在super.start()方法中调用createAndAddWindows()方法,

 @Override
    public void createAndAddWindows() {
        addStatusBarWindow();
    }

    private void addStatusBarWindow() {
        // Put up the view
        final int height = getStatusBarHeight();

        // Now that the status bar window encompasses the sliding panel and its
        // translucent backdrop, the entire thing is made TRANSLUCENT and is
        // hardware-accelerated.
        final WindowManager.LayoutParams lp = new WindowManager.LayoutParams(
                ViewGroup.LayoutParams.MATCH_PARENT,
                height,
                WindowManager.LayoutParams.TYPE_STATUS_BAR,
                WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
                    | WindowManager.LayoutParams.FLAG_TOUCHABLE_WHEN_WAKING
                    | WindowManager.LayoutParams.FLAG_SPLIT_TOUCH,
                PixelFormat.TRANSLUCENT);

        lp.flags |= WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED;

        lp.gravity = getStatusBarGravity();
        lp.setTitle("StatusBar");
        lp.packageName = mContext.getPackageName();

        makeStatusBarView();
        mWindowManager.addView(mStatusBarWindow, lp);
    }

2.将NavigationBar添加到WindowManager中

addNavigationBar()

    // For small-screen devices (read: phones) that lack hardware navigation buttons
    private void addNavigationBar() {
        if (DEBUG) Slog.v(TAG, "addNavigationBar: about to add " + mNavigationBarView);
        if (mNavigationBarView == null) return;

        prepareNavigationBarView();

        mWindowManager.addView(mNavigationBarView, getNavigationBarLayoutParams());
    }

3.实例化PhoneStatusBarPolicy