Android 4.0 ICS SystemUI浅析——StatusBar加载流程分析

前面两篇文章《Android
4.0 ICS SystemUI浅析——SystemUI启动流程》、《Android
4.0 ICS SystemUI浅析——StatusBar结构分析》SystemUI和StatusBar的冰山一角，那么本文将从代码的角度来分析StatusBar的加载流程。

本文来自：http://blog.csdn.net/yihongyuelan 欢迎转载 请务必注明出处！

在《Android
4.0 ICS SystemUI浅析——SystemUI启动流程》中，我们提到了在Phone中，整个StatusBar和NavigationBar都是在/SourceCode/frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java的start()方法中，完成初始化并显示到界面上的。因此，我们回到这段代码中查看：

[java] view
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@Override

public void start() {

mDisplay = ((WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE))

.getDefaultDisplay();

mWindowManager = IWindowManager.Stub.asInterface(

ServiceManager.getService(Context.WINDOW_SERVICE));

super.start(); // calls makeStatusBarView() 这里会调用父类StatusBar.java中的start()方法

addNavigationBar();//加载导航栏，本文因以StatusBar为主，因此暂不分析NavigationBar

//addIntruderView();

// Lastly, call to the icon policy to install/update all the icons.

mIconPolicy = new PhoneStatusBarPolicy(mContext);//用于初始化以及更新StatusBar上的icons

}

我们继续跟踪super.start()方法，来到/SourceCode/frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/StatusBar.java的start()方法中，如代码所示：

[java] view
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public void start() {

// First set up our views and stuff.首先准备我们需要显示的view以及原材料

//我们先跟踪这里的makeStatusBarView

View sb = makeStatusBarView();

// Connect in to the status bar manager service

StatusBarIconList iconList = new StatusBarIconList();

ArrayList<IBinder> notificationKeys = new ArrayList<IBinder>();

ArrayList<StatusBarNotification> notifications = new ArrayList<StatusBarNotification>();

... ...

通过Open Implementation跳转到makeStatusBarView的实现，因为我们是针对Phone来分析的，因此选择PhoneStatusBar，代码如下：

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// ================================================================================

// Constructing the view

// ================================================================================

protected View makeStatusBarView() {

final Context context = mContext;

Resources res = context.getResources();

//获取ExpandedView的尺寸

updateDisplaySize(); // populates mDisplayMetrics

//定义icon的大小，缩放率和彼此间距

loadDimens();

mIconSize = res.getDimensionPixelSize(com.android.internal.R.dimen.status_bar_icon_size);

//设置ExpandedView的布局

ExpandedView expanded = (ExpandedView)View.inflate(context,

R.layout.status_bar_expanded, null);

if (DEBUG) {

expanded.setBackgroundColor(0x6000FF80);

}

expanded.mService = this;

//前面已注释，以下三段代码没有用到

mIntruderAlertView = View.inflate(context, R.layout.intruder_alert, null);

mIntruderAlertView.setVisibility(View.GONE);

mIntruderAlertView.setClickable(true);

PhoneStatusBarView sb;

//这里根据是否是双卡来加载不同的布局文件

if (TelephonyManager.getDefault().isMultiSimEnabled()) {

sb = (PhoneStatusBarView)View.inflate(context,

R.layout.msim_status_bar, null);

} else {

sb = (PhoneStatusBarView)View.inflate(context,

R.layout.status_bar, null);

}

sb.mService = this;

mStatusBarView = sb;

//是否显示NavigationBar

try {

boolean showNav = mWindowManager.hasNavigationBar();

if (showNav) {

mNavigationBarView =

(NavigationBarView) View.inflate(context, R.layout.navigation_bar, null);

mNavigationBarView.setDisabledFlags(mDisabled);

}

} catch (RemoteException ex) {

// no window manager? good luck with that

}

// figure out which pixel-format to use for the status bar.

mPixelFormat = PixelFormat.OPAQUE;

//系统状态图标布局初始化

mStatusIcons = (LinearLayout)sb.findViewById(R.id.statusIcons);

//通知图标布局初始化

mNotificationIcons = (IconMerger)sb.findViewById(R.id.notificationIcons);

mMoreIcon = sb.findViewById(R.id.moreIcon);

mNotificationIcons.setOverflowIndicator(mMoreIcon);

//icons布局初始化，该布局用于装载除开tiker外的所有控件

mIcons = (LinearLayout)sb.findViewById(R.id.icons);

//ticker布局初始化

mTickerView = sb.findViewById(R.id.ticker);

//以上几个重要布局的关系在上一篇文章有详细分析

//以下几段代码是在设置ExpandedView，ExpandedDialog通过加载ExpandedView显示，其中包括了ExpanedView上的清除按钮，

//设置按钮，滚动条，日期显示等等

mExpandedDialog = new ExpandedDialog(context);

mExpandedView = expanded;

mPile = (NotificationRowLayout)expanded.findViewById(R.id.latestItems);

mExpandedContents = mPile; // was: expanded.findViewById(R.id.notificationLinearLayout);

mNoNotificationsTitle = (TextView)expanded.findViewById(R.id.noNotificationsTitle);

mNoNotificationsTitle.setVisibility(View.GONE); // disabling for now

mClearButton = expanded.findViewById(R.id.clear_all_button);

mClearButton.setOnClickListener(mClearButtonListener);

mClearButton.setAlpha(0f);

mClearButton.setEnabled(false);

mDateView = (DateView)expanded.findViewById(R.id.date);

mSettingsButton = expanded.findViewById(R.id.settings_button);

mSettingsButton.setOnClickListener(mSettingsButtonListener);

mScrollView = (ScrollView)expanded.findViewById(R.id.scroll);

//tickerView的初始化

mTicker = new MyTicker(context, sb);

TickerView tickerView = (TickerView)sb.findViewById(R.id.tickerText);

tickerView.mTicker = mTicker;

//TrackingView初始化

mTrackingView = (TrackingView)View.inflate(context, R.layout.status_bar_tracking, null);

mTrackingView.mService = this;

mCloseView = (CloseDragHandle)mTrackingView.findViewById(R.id.close);

mCloseView.mService = this;

mEdgeBorder = res.getDimensionPixelSize(R.dimen.status_bar_edge_ignore);

// set the inital view visibility

setAreThereNotifications();

// Other icons

//以下是对其他icons的加载(信号及电量图标的加载)

mLocationController = new LocationController(mContext); // will post a notification

mBatteryController = new BatteryController(mContext);

mBatteryController.addIconView((ImageView)sb.findViewById(R.id.battery));

SignalClusterView signalCluster;

LinearLayout mSimSignalView;

//根据是否是双卡加载不同的布局文件

if (TelephonyManager.getDefault().isMultiSimEnabled()) {

mMSimNetworkController = new MSimNetworkController(mContext);

mSimSignalView = (LinearLayout) sb.findViewById(R.id.msim_signal_cluster);

if (FeatureQuery.FEATURE_ANNUCIATOR_NEW_STATUSBAR_STYLE) {

CUMSimSignalClusterView cuMSimSignalCluster = (CUMSimSignalClusterView)View.inflate(context, R.layout.msim_signal_cluster_view_cu, null);

mSimSignalView.addView(cuMSimSignalCluster);

for (int i=0; i < TelephonyManager.getDefault().getPhoneCount(); i++) {

mMSimNetworkController.addSignalCluster(cuMSimSignalCluster, i);

}

cuMSimSignalCluster.setNetworkController(mMSimNetworkController);

} else {

MSimSignalClusterView mSimSignalCluster = (MSimSignalClusterView)View.inflate(context, R.layout.msim_signal_cluster_view, null);

mSimSignalView.addView(mSimSignalCluster);

for (int i=0; i < TelephonyManager.getDefault().getPhoneCount(); i++) {

mMSimNetworkController.addSignalCluster(mSimSignalCluster, i);

}

mSimSignalCluster.setNetworkController(mMSimNetworkController);

}

} else {

mNetworkController = new NetworkController(mContext);

signalCluster = (SignalClusterView)sb.findViewById(R.id.signal_cluster);

mNetworkController.addSignalCluster(signalCluster);

signalCluster.setNetworkController(mNetworkController);

// final ImageView wimaxRSSI =

// (ImageView)sb.findViewById(R.id.wimax_signal);

// if (wimaxRSSI != null) {

// mNetworkController.addWimaxIconView(wimaxRSSI);

// }

}

// Recents Panel

//最近使用界面初始化

mRecentTasksLoader = new RecentTasksLoader(context);

updateRecentsPanel();

// receive broadcasts

//注册广播监听器

IntentFilter filter = new IntentFilter();

filter.addAction(Intent.ACTION_CONFIGURATION_CHANGED);

filter.addAction(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);

filter.addAction(Intent.ACTION_SCREEN_ON);

filter.addAction(Intent.ACTION_SCREEN_OFF);

context.registerReceiver(mBroadcastReceiver, filter);

return sb;

}

通过makeStatusBarView()我们可以看到，在该方法中整个StatusBar根据获取的设备配置信息进行了布局，就好比我们去吃饭，先要安排好座位和桌子，最后才上菜，我们需要加载的icons——就是菜！！:D

我们回到StatusBar.java的start()方法中继续分析，代码如下：

[java] view
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public void start() {

// First set up our views and stuff.首先准备我们需要显示的view以及原材料

//我们先跟踪这里的makeStatusBarView

View sb = makeStatusBarView();

// Connect in to the status bar manager service

//初始化各个存储器，用于存储各类信息，这些信息通过StatusBarManagerService获取

//iconsList用于存放icons

StatusBarIconList iconList = new StatusBarIconList();

//nodificationKeys保存以Binder为Key的notification

ArrayList<IBinder> notificationKeys = new ArrayList<IBinder>();

//保存StatusBarNotification类型的notifications

ArrayList<StatusBarNotification> notifications = new ArrayList<StatusBarNotification>();

//mCommandQueue是和IStatusBarService进行交互的IBinder

mCommandQueue = new CommandQueue(this, iconList);

//这里实际上获取的是StatusBarManagerService

mBarService = IStatusBarService.Stub.asInterface(

ServiceManager.getService(Context.STATUS_BAR_SERVICE));

int[] switches = new int[7];

ArrayList<IBinder> binders = new ArrayList<IBinder>();

try {

//通过StatusBarManagerService中的registerStatusBar来获取初始设置

mBarService.registerStatusBar(mCommandQueue, iconList, notificationKeys, notifications,

switches, binders);

} catch (RemoteException ex) {

// If the system process isn't there we're doomed anyway.

}

//对SystemUI上像Clock、ExpandedView、NavigationBar等进行初始化设置

disable(switches[0]);

setSystemUiVisibility(switches[1]);

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]);

setHardKeyboardStatus(switches[5] != 0, switches[6] != 0);

// Set up the initial icon state

//icon加载(注：陷阱!!!一不注意就会迷失！！后文详将细分析)

int N = iconList.size();

int viewIndex = 0;

for (int i=0; i<N; i++) {

StatusBarIcon icon = iconList.getIcon(i);

if (icon != null) {

addIcon(iconList.getSlot(i), i, viewIndex, icon);

viewIndex++;

}

}

// Set up the initial notification state

//加载notifications

N = notificationKeys.size();

if (N == notifications.size()) {

for (int i=0; i<N; i++) {

addNotification(notificationKeys.get(i), notifications.get(i));

}

} else {

Log.wtf(TAG, "Notification list length mismatch: keys=" + N

+ " notifications=" + notifications.size());

}

// Put up the view

//获取StatusBar高度

final int height = getStatusBarHeight();

//设置lp各种属性

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,

// We use a pixel format of RGB565 for the status bar to save memory bandwidth and

// to ensure that the layer can be handled by HWComposer. On some devices the

// HWComposer is unable to handle SW-rendered RGBX_8888 layers.

PixelFormat.RGB_565);

// the status bar should be in an overlay if possible

final Display defaultDisplay

= ((WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE))

.getDefaultDisplay();

//enable hardware acceleration based on device

//使能硬件加速，不过只有Tablet上才有用

setHardwareAcceleration(lp);

lp.gravity = getStatusBarGravity();

lp.setTitle("StatusBar");

lp.packageName = mContext.getPackageName();

lp.windowAnimations = R.style.Animation_StatusBar;

//在Window上显示StatusBar界面

WindowManagerImpl.getDefault().addView(sb, lp);

mDoNotDisturb = new DoNotDisturb(mContext);

}

可能大多数朋友都还是云里雾里的，先别急，我们只是把大致流程走完了，细节还没有去分析，接下来我们再来看看StatusBar到底是如何加载Icons的。

需要分析如何加载Icons，首先我们根据StatusBar.java中的start()方法可以看到，addIcon()方法完成了Icons的加载。那么通过Open Implementation跳转到PhoneStatusBar.java中的addIcon()方法中(因为我们之前传递的Context是PhoneStatusBar的)，代码如下：

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public void addIcon(String slot, int index, int viewIndex, StatusBarIcon icon) {

if (SPEW) Slog.d(TAG, "addIcon slot=" + slot + " index=" + index + " viewIndex=" + viewIndex

+ " icon=" + icon);

//初始化StatusBarIconView

StatusBarIconView view = new StatusBarIconView(mContext, slot, null);

//加载icon

view.set(icon);

//这里的FEATURE_ANNUCIATOR_NEW_STATUSBAR_STYLE是高通自己定义的，默认为true

if (FeatureQuery.FEATURE_ANNUCIATOR_NEW_STATUSBAR_STYLE) {

//将设置好icon的StatusBarIconView加载到mStatusIcons布局中

mStatusIcons.addView(view, viewIndex, new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, mIconSize));

} else {

mStatusIcons.addView(view, viewIndex, new LinearLayout.LayoutParams(mIconSize, mIconSize));

}

}

整个加载过程从表面上看来只有3步，但从本质上来讲远远不止3步。首先，我们先来看看addIcon(...)方法所传递的值；我将这里Slog中的内容打印出来，结果如下：

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addIcon slot=tty index=6 viewIndex=0 icon=StatusBarIcon(pkg=com.android.systemui id=0x7f02012b level=0 visible=false num=0 )

addIcon slot=cdma_eri index=11 viewIndex=1 icon=StatusBarIcon(pkg=com.android.systemui id=0x7f0200d8 level=0 visible=false num=0 )

addIcon slot=bluetooth index=4 viewIndex=0 icon=StatusBarIcon(pkg=com.android.systemui id=0x7f020073 level=0 visible=false num=0 )

addIcon slot=alarm_clock index=18 viewIndex=3 icon=StatusBarIcon(pkg=com.android.systemui id=0x7f020060 level=0 visible=false num=0 )

addIcon slot=sync_active index=2 viewIndex=0 icon=StatusBarIcon(pkg=com.android.systemui id=0x7f020129 level=0 visible=false num=0 )

addIcon slot=sync_failing index=1 viewIndex=0 icon=StatusBarIcon(pkg=com.android.systemui id=0x7f02012a level=0 visible=false num=0 )

addIcon slot=volume index=9 viewIndex=4 icon=StatusBarIcon(pkg=com.android.systemui id=0x7f0200d6 level=0 visible=false num=0 )

addIcon slot=headset index=16 viewIndex=6 icon=StatusBarIcon(pkg=com.android.systemui id=0x7f02000a level=0 visible=false num=0 )

通过以上log，其中的tty表示语音图标，cdma_eri表示CDMA漫游时显示的图标，其他的大家应该都认识吧，这里就不多讲了。也就是说addIcon()加载的是系统的状态图标。那么我们继续查看它到底是如何加载的，继续查看StatusBarIconView()方法，代码如下：

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public StatusBarIconView(Context context, String slot, Notification notification) {

super(context);

//获取资源

final Resources res = context.getResources();

mSlot = slot;

//画笔初始化

mNumberPain = new Paint();

mNumberPain.setTextAlign(Paint.Align.CENTER);

mNumberPain.setColor(res.getColor(R.drawable.notification_number_text_color));

mNumberPain.setAntiAlias(true);

mNotification = notification;

setContentDescription(notification);

// We do not resize and scale system icons (on the right), only notification icons (on the

// left).

if (notification != null) {

final int outerBounds = res.getDimensionPixelSize(R.dimen.status_bar_icon_size);

final int imageBounds = res.getDimensionPixelSize(R.dimen.status_bar_icon_drawing_size);

final float scale = (float)imageBounds / (float)outerBounds;

setScaleX(scale);

setScaleY(scale);

final float alpha = res.getFraction(R.dimen.status_bar_icon_drawing_alpha, 1, 1);

setAlpha(alpha);

}

//按图片原来的size居中显示

setScaleType(ImageView.ScaleType.CENTER);

}

通过查看StatusBarIconView的继承关系我们可以发现public class StatusBarIconView extends AnimatedImageView ，继续跟踪可以看到public class AnimatedImageView extends ImageView，也就是说我们的StatusBarIconView其实就是一个封装过的ImageView，这样自然能够盛放我们的Icons了。继续查看StatusBarIconView的set()方法，代码如下：

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/**

* Returns whether the set succeeded.

*/

public boolean set(StatusBarIcon icon) {

final boolean iconEquals = mIcon != null

&& streq(mIcon.iconPackage, icon.iconPackage)

&& mIcon.iconId == icon.iconId;

final boolean levelEquals = iconEquals

&& mIcon.iconLevel == icon.iconLevel;

final boolean visibilityEquals = mIcon != null

&& mIcon.visible == icon.visible;

final boolean numberEquals = mIcon != null

&& mIcon.number == icon.number;

//将icon的信息copy到mIcon中

mIcon = icon.clone();

setContentDescription(icon.contentDescription);

//获取icon图片并设置到StatusBarIconView中去

if (!iconEquals) {

Drawable drawable = getIcon(icon);

if (drawable == null) {

Slog.w(StatusBar.TAG, "No icon for slot " + mSlot);

return false;

}

setImageDrawable(drawable);

}

//设置需要显示的图片

if (!levelEquals) {

setImageLevel(icon.iconLevel);

}

//这个不太清楚具体是干嘛的

if (!numberEquals) {

if (icon.number > 0 && mContext.getResources().getBoolean(

R.bool.config_statusBarShowNumber)) {

if (mNumberBackground == null) {

mNumberBackground = getContext().getResources().getDrawable(

R.drawable.ic_notification_overlay);

}

placeNumber();

} else {

mNumberBackground = null;

mNumberText = null;

}

invalidate();

}

//设置是否可见

if (!visibilityEquals) {

setVisibility(icon.visible ? VISIBLE : GONE);

}

return true;

}

到这一步时，我们已经将系统的Icons设置到了mStatusIcons这个mStatusIcons的LinearLayout上了。

但是，事实真的如此吗？这样就完成icons的初始化了吗？还是那句话，实践是检验真理是否正确的唯一标准！那么我们在PhoneStatusBar.java的addIcon()方法中，加入代码，将程序调用栈打印出来，结果一看便知(当然，也可以用Eclipse的远程调试)！加入代码如下：

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StackTraceElement st[]= Thread.currentThread().getStackTrace();

for(int i=0;i<st.length;i++)

System.out.println(i+":"+st[i]);

重新编译SystemUI，push到/system/app目录下，重新启动，打印部分log如下：

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I/System.out(420): 0:dalvik.system.VMStack.getThreadStackTrace(Native Method)

I/System.out(420): 1:java.lang.Thread.getStackTrace(Thread.java:591)

I/System.out(420): 2:com.android.systemui.statusbar.phone.PhoneStatusBar.addIcon(PhoneStatusBar.java:562)

I/System.out(420): 3:com.android.systemui.statusbar.CommandQueue$H.handleMessage(CommandQueue.java:212)

I/System.out(420): 4:android.os.Handler.dispatchMessage(Handler.java:99)

I/System.out(420): 5:android.os.Looper.loop(Looper.java:137)

I/System.out(420): 6:android.app.ActivityThread.main(ActivityThread.java:4450)

I/System.out(420): 7:java.lang.reflect.Method.invokeNative(Native Method)

I/System.out(420): 8:java.lang.reflect.Method.invoke(Method.java:511)

I/System.out(420): 9:com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:787)

I/System.out(420): 10:com.android.internal.os.ZygoteInit.main(ZygoteInit.java:554)

I/System.out(420): 11:dalvik.system.NativeStart.main(Native Method)

... ...

从打印出来的调用栈，我们可以发现，实际条用addIcon()方法的，并不是我们之前分析的StatusBar，而是来自CommandQueue中的handleMessage，这和我们之前的分析大相径庭啊！也就是说实际上addIcon()在CommandQueue中被调用了，那么我们就反过来分析，直接去CommandQueue.java中的handleMessage找到addIcon()。代码如下：

[java] view
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case OP_SET_ICON: {

StatusBarIcon icon = (StatusBarIcon)msg.obj;

StatusBarIcon old = mList.getIcon(index);

if (old == null) {

mList.setIcon(index, icon);

mCallbacks.addIcon(mList.getSlot(index), index, viewIndex, icon);

} else {

mList.setIcon(index, icon);

mCallbacks.updateIcon(mList.getSlot(index), index, viewIndex,

old, icon);

}

break;

}

通过case OP_SET_ICON我们可以继续追查，我们可以查到是谁发送的这个message，代码如下：

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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();

}

}

在CommandQueue中的setIcon发送了这个消息，通过Open Call Hierarchy继续追查，可以看到如图1：



图 1

其中第一个onTransact是一个IBinder，后两者是StatusBarManagerService中的方法。通过方法名称，我们可以大致猜测，setIcon是设置Icon，setIconVisibility是这是Icon是否可见，我们从逻辑上分析，如果是开机第一次调用我们应该先设置Icon然后再考虑设置其可见性(看完后文就会明白了:D)。我们直接跳转到StatusBarManagerService中的setIcon()方法，代码如下：

[java] view
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public void setIcon(String slot, String iconPackage, int iconId, int iconLevel,

String contentDescription) {

enforceStatusBar();

synchronized (mIcons) {

int index = mIcons.getSlotIndex(slot);//这里会检查是否是未定义的icon，如果是则抛出异常

if (index < 0) {

throw new SecurityException("invalid status bar icon slot: " + slot);

}

StatusBarIcon icon = new StatusBarIcon(iconPackage, 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);//这里调用的

} catch (RemoteException ex) {

}

}

}

}

继续用Open Call Hierarchy查找哪里调用的setIcon方法，如图2：



图 2

这里一看就知道应该是StatusBarManager中的setIcon嘛，继续跟踪，代码如下：

[java] view
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public void setIcon(String slot, int iconId, int iconLevel, String contentDescription) {

try {

final IStatusBarService svc = getService();

if (svc != null) {

svc.setIcon(slot, mContext.getPackageName(), iconId, iconLevel,

contentDescription);//这里调用的

}

} catch (RemoteException ex) {

// system process is dead anyway.

throw new RuntimeException(ex);

}

}

目前看来还不是很清晰，继续查找，如图3：



图 3

看到这里请不要头晕，因为真相就在眼前！那么这里应该是谁在调用呢？在本文的一开始，我们就分析了/SourceCode/frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java的start()方法，在该方法中有如下代码：

[java] view
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mIconPolicy = new PhoneStatusBarPolicy(mContext);

该代码不正是调用了PhoneStatusBarPolicy()构造方法吗？直接跟进去，代码如下：

[java] view
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public PhoneStatusBarPolicy(Context context) {

... ...

// listen for broadcasts

IntentFilter filter = new IntentFilter();

filter.addAction(Intent.ACTION_ALARM_CHANGED);

filter.addAction(Intent.ACTION_SYNC_STATE_CHANGED);

filter.addAction(AudioManager.RINGER_MODE_CHANGED_ACTION);

filter.addAction(AudioManager.VIBRATE_SETTING_CHANGED_ACTION);

filter.addAction(BluetoothAdapter.ACTION_STATE_CHANGED);

filter.addAction(Intent.ACTION_HEADSET_PLUG); // ted add 2021-4-24

filter.addAction(BluetoothAdapter.ACTION_CONNECTION_STATE_CHANGED);

filter.addAction(TelephonyIntents.ACTION_SIM_STATE_CHANGED);

filter.addAction(TtyIntent.TTY_ENABLED_CHANGE_ACTION);

mContext.registerReceiver(mIntentReceiver, filter, null, mHandler);

... ...

// TTY status

mService.setIcon("tty", R.drawable.stat_sys_tty_mode, 0, null);//这里调用

mService.setIconVisibility("tty", false);

// Cdma Roaming Indicator, ERI

mService.setIcon("cdma_eri", R.drawable.stat_sys_roaming_cdma_0, 0, null);//这里调用

mService.setIconVisibility("cdma_eri", false);

... ...

mService.setIcon("bluetooth", bluetoothIcon, 0, null);//这里调用

mService.setIconVisibility("bluetooth", mBluetoothEnabled);

// Alarm clock

mService.setIcon("alarm_clock", R.drawable.stat_sys_alarm, 0, null);//这里调用

mService.setIconVisibility("alarm_clock", false);

// Sync state

mService.setIcon("sync_active", R.drawable.stat_sys_sync, 0, null);//这里调用

mService.setIcon("sync_failing", R.drawable.stat_sys_sync_error, 0, null);//这里调用

mService.setIconVisibility("sync_active", false);

mService.setIconVisibility("sync_failing", false);

// volume

mService.setIcon("volume", R.drawable.stat_sys_ringer_silent, 0, null);//这里调用

mService.setIconVisibility("volume", false);

updateVolume();

// headset

mService.setIcon("headset", R.drawable.ckt_headset_with_mic, 0, null);//这里调用

mService.setIconVisibility("headset", false);

}

这里也同时验证了我们前面的猜想，即先设置Icon再设置其可见性。也许你会认为本文到这里已经完结了(太长了，一次看不完...o(╯□╰)o)，但有个别地方我还得再提一下，Android 启动之后，在SystemServer.java的run方法中，调用了StatusBarManagerService的构造方法，代码如下：

[java] view
plaincopy

... ...

try {

Slog.i(TAG, "Status Bar");

statusBar = new StatusBarManagerService(context, wm);

ServiceManager.addService(Context.STATUS_BAR_SERVICE, statusBar);

} catch (Throwable e) {

reportWtf("starting StatusBarManagerService", e);

}

... ...

在StatusBarManagerService的构造方法中，代码如下：

[java] view
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public StatusBarManagerService(Context context, WindowManagerService windowManager) {

mContext = context;

mWindowManager = windowManager;

mWindowManager.setOnHardKeyboardStatusChangeListener(this);

final Resources res = context.getResources();

//这里加载了系统预置的所有icon，路径在：Sourcecode/framework/base/core/res/res/values/config.xml中

mIcons.defineSlots(res.getStringArray(com.android.internal.R.array.config_statusBarIcons));

}

其中Sourcecode/framework/base/core/res/res/values/config.xml中的预置图标定义如下：

[html] view
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<string-array name="config_statusBarIcons">

<item><xliff:g id="id">ime</xliff:g></item>

<item><xliff:g id="id">sync_failing</xliff:g></item>

<item><xliff:g id="id">sync_active</xliff:g></item>

<item><xliff:g id="id">gps</xliff:g></item>

<item><xliff:g id="id">bluetooth</xliff:g></item>

<item><xliff:g id="id">nfc</xliff:g></item>

<item><xliff:g id="id">tty</xliff:g></item>

<item><xliff:g id="id">speakerphone</xliff:g></item>

<item><xliff:g id="id">mute</xliff:g></item>

<item><xliff:g id="id">volume</xliff:g></item>

<item><xliff:g id="id">wifi</xliff:g></item>

<item><xliff:g id="id">cdma_eri</xliff:g></item>

<item><xliff:g id="id">phone_signal_second_sub</xliff:g></item>

<item><xliff:g id="id">data_connection</xliff:g></item>

<item><xliff:g id="id">phone_evdo_signal</xliff:g></item>

<item><xliff:g id="id">phone_signal</xliff:g></item>

<item><xliff:g id="id">headset</xliff:g></item>

<item><xliff:g id="id">battery</xliff:g></item>

<item><xliff:g id="id">alarm_clock</xliff:g></item>

<item><xliff:g id="id">secure</xliff:g></item>

<item><xliff:g id="id">clock</xliff:g></item>

</string-array>

这些东西在后文判断时都会用到，在此记录用以备忘。

Update 20120810 时序图和UML图：



图 4



图 5

小结

本文主要是对StatusBar上面的Icons的加载进行了较为细致的分析，后面将继续分析各个部件的加载以及工作流程。其中自己也走了不少弯路，但还是想记录下载，毕竟没有谁从一开始就能做正确吧！将此总结分享出来希望能给各位一些帮助，同时也给自己一些激励，希望自己后面能做的更好。本文主要是枯燥的代码调用与追踪，但对于需要的朋友，我想还是很有帮助的，后面会将相关的时序图以及UML图贴出来，以供参考