android SystemUI详解

状态栏(status_bar.xml)

主要由四部分组成, 

1.SigalClusterView (电池 基站信号)   

2.notification_icon_area(消息推送图标区) 

3.status_icons  包括静音icon 蓝牙icon 等共9个左右

4.下拉之后的view

状态icons：

SystemUI 第一次启动堆栈：

D/yzy     (13114): com.android.systemui.statusbar.phone.PhoneStatusBar.addIcon(...)//添加状态icon
D/yzy     (13114): com.android.systemui.statusbar.BaseStatusBar.start(...)
D/yzy     (13114): com.android.systemui.statusbar.phone.PhoneStatusBar.bindViews(...)
D/yzy     (13114): com.android.systemui.statusbar.phone.PhoneStatusBar.start(...)
D/yzy     (13114): com.android.systemui.SystemUIService.onCreate(...)

D/yzy     (13114): android.app.ActivityThread.handleCreateService(...)
D/yzy     (13114): android.app.ActivityThread.access$1600(...)
D/yzy     (13114): android.app.ActivityThread$H.handleMessage(...)
D/yzy     (13114): android.os.Handler.dispatchMessage(...)
D/yzy     (13114): android.os.Looper.loop(...)
D/yzy     (13114): android.app.ActivityThread.main(...)
D/yzy     (13114): java.lang.reflect.Method.invokeNative(...)
D/yzy     (13114): java.lang.reflect.Method.invoke(...)
D/yzy     (13114): com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(...)
D/yzy     (13114): com.android.internal.os.ZygoteInit.main(...)
D/yzy     (13114): dalvik.system.NativeStart.main(...)

BaseStatusBar.start(...)：

 // Connect in to the status bar manager service
        StatusBarIconList iconList = new StatusBarIconList();
        ArrayList<IBinder> notificationKeys = new ArrayList<IBinder>();
        ArrayList<StatusBarNotification> notifications = new ArrayList<StatusBarNotification>();
        mCommandQueue.registerCallbacks(this, iconList);

        int[] switches = new int[7];
        ArrayList<IBinder> binders = new ArrayList<IBinder>();
        try {
            mBarService.registerStatusBar(mCommandQueue, iconList, notificationKeys, notifications,
                    switches, binders);
        } catch (RemoteException ex) {
            // If the system process isn't there we're doomed anyway.
        }

当插入耳机的时候PhoneStatusBarPolicy   updateHeadset 

mService 是 StatusBarManagerService 的客户端

mService.setIcon("headset", icon, 0, null);
        mService.setIconVisibility("headset", plug);

通过AIDL 调用了StatusBarManagerService的 setIcon ，可是为什么这样调用之后 icon就显示出来了呢？

OK ！ 是CommandQueue登场了，它正是binder 的 客户端。

public void setIcon(String slot, String iconPackage, int iconId, int iconLevel,
            String contentDescription) {
        enforceStatusBar();

        synchronized (mIcons) {
            int index = mIcons.getSlotIndex(slot);
            if (index < 0) {
                throw new SecurityException("invalid status bar icon slot: " + slot);
            }

            StatusBarIcon icon = new StatusBarIcon(iconPackage, UserHandle.OWNER, iconId,
                    iconLevel, 0,
                    contentDescription);
            //Slog.d(TAG, "setIcon slot=" + slot + " index=" + index + " icon=" + icon);
            mIcons.setIcon(index, icon);

            if (mBar != null) {
                try {
                    mBar.setIcon(index, icon);
                } catch (RemoteException ex) {
                }
            }
        }
    }

CommandQueue.java

 public void setIcon(int index, StatusBarIcon icon) {
        synchronized (mList) {
            int what = MSG_ICON | index;
            mHandler.removeMessages(what);
            mHandler.obtainMessage(what, OP_SET_ICON, 0, icon.clone()).sendToTarget();
        }
    }

之后SystemUI自己处理该message，来添加状态icon。

notification Icon

那第三方应用发送的通知是如何显示到状态栏的呢？

第三方应用：
NotificationManager.notify( Notification notification)
--->NotificationManagerService.enqueueNotificationWithTag
--->StatusBarManagerService.addNotification
---->IStatusBar.addNotification
-->执行SystemUI中的CommandQueue extends IStatusBar.Stub extends IStatusBar addNotification( Notification notification)

涉及到了 第三方应用 systemServer  SystemUI 三个进程之间的binder通信,remoteViews.apply创建了实际的View

remoteView 实现进程间view的传递,如AppWidget  Notification。