SystemUI 开发之服务组件概览（二）

    <!-- SystemUI Services: The classes of the stuff to start. -->
    <string-array name="config_systemUIServiceComponents" translatable="false">
        <item>com.android.systemui.util.NotificationChannels</item>
        <item>com.android.systemui.keyguard.KeyguardViewMediator</item>
        <item>com.android.systemui.recents.Recents</item>
        <item>com.android.systemui.volume.VolumeUI</item>
        <item>com.android.systemui.statusbar.phone.StatusBar</item>
        <item>com.android.systemui.usb.StorageNotification</item>
        <item>com.android.systemui.power.PowerUI</item>
        <item>com.android.systemui.media.RingtonePlayer</item>
        <item>com.android.systemui.keyboard.KeyboardUI</item>
        <item>com.android.systemui.shortcut.ShortcutKeyDispatcher</item>
        <item>@string/config_systemUIVendorServiceComponent</item>
        <item>com.android.systemui.util.leak.GarbageMonitor$Service</item>
        <item>com.android.systemui.LatencyTester</item>
        <item>com.android.systemui.globalactions.GlobalActionsComponent</item>
        <item>com.android.systemui.ScreenDecorations</item>
        <item>com.android.systemui.biometrics.AuthController</item>
        <item>com.android.systemui.SliceBroadcastRelayHandler</item>
        <item>com.android.systemui.statusbar.notification.InstantAppNotifier</item>
        <item>com.android.systemui.theme.ThemeOverlayController</item>
        <item>com.android.systemui.accessibility.WindowMagnification</item>
        <item>com.android.systemui.accessibility.SystemActions</item>
        <item>com.android.systemui.toast.ToastUI</item>
        <item>com.android.systemui.wmshell.WMShell</item>
    </string-array>

com.android.systemui.Dependency
提供依赖注入实现（这个在最新的源码 config_systemUIServiceComponents 里面已经是没有了，但如果你看 Android 10 这个类还是存在的）

com.android.systemui.util.NotificationChannels
用来处理通知的逻辑

com.android.systemui.keyguard.KeyguardViewMediator
用来处理键盘锁状态

com.android.systemui.recents.Recents
处理最新任务列表的逻辑

com.android.systemui.volume.VolumeUI
监听音量，并决定是否显示音量的对话框

com.android.systemui.status.phone.StatusBar
状态栏，也包含了通知栏和其它重要的 UI 交互，例如键盘锁等。这里也会监听通知

com.android.systemui.usb.StorageNotification
监听 USB 连接状态并发送通知进行提示

com.android.systemui.power.PowerUI
监听电量状态并在低电量时发送通知

com.android.systemui.media.RingtonePlayer
用于播放铃声

com.android.systemui.keyboard.KeyboardUI
键盘锁 UI

com.android.systemui.shortcut.ShortcutKeyDispatcher
向 SystemUI 组件派发快捷键

@string/config_systemUIVendorServiceComponent
这里可以定义厂商定制的组件

com.android.systemui.util.leak.GarbageMonitor$Service
用于监控内存泄漏的服务

com.android.systemui.LatencyTester
仅在 debug 环境执行，用于监听系统测试延迟的模拟动作

com.android.systemui.globalactions.GlobalActionsComponent
用于显示全局对话框（例如长按电源按键）

com.android.systemui.ScreenDecorations
处理页面中的显示的形状（如圆角）

com.android.systemui.biometrics.BiometricDialogImpl
生物识别 UI （如指纹识别、解锁等页面？）

com.android.systemui.wmshell.WMShell
转发 SysUI 事件到 WM Shell

/**
 * A top-level module of system UI code (sometimes called "system UI services" elsewhere in code).
 * Which SystemUI modules are loaded can be controlled via a config resource.
 *
 * @see SystemUIApplication#startServicesIfNeeded()
 */
public abstract class SystemUI implements Dumpable {
    protected final Context mContext;

    public SystemUI(Context context) {
        mContext = context;
    }

    public abstract void start();

    protected void onConfigurationChanged(Configuration newConfig) {
    }

    @Override
    public void dump(@NonNull FileDescriptor fd, @NonNull PrintWriter pw, @NonNull String[] args) {
    }

    protected void onBootCompleted() {
    }

    public static void overrideNotificationAppName(Context context, Notification.Builder n,
            boolean system) {
        final Bundle extras = new Bundle();
        String appName = system
                ? context.getString(com.android.internal.R.string.notification_app_name_system)
                : context.getString(com.android.internal.R.string.notification_app_name_settings);
        extras.putString(Notification.EXTRA_SUBSTITUTE_APP_NAME, appName);
        n.addExtras(extras);
    }
}