学习条记：SystemUI StatusBar 手机信号相干图标的表现和更新流程分析
这里StatuBar的创建就不说了，前面已经说过了。
SystemUI中StatusBar的图标控制器实现类为StatusBarIconControllerImpl，其继承了StatusBarIconController的接口，用于跟踪全部图标的状态，并将对应的状态发送给注册的图标管理器(IconManagers)。当我们在StatusBar中获取到它的实例后，还会将它传给PhoneStatusBarPolicy和StatusBarSignalPolicy对象。PhoneStatusBarPolicy控制启动时装载哪些图标（蓝牙，定位等），而StatusBarSignalPolicy控制网络信号图标（移动网络，WiFi，以太网）的变革。
一起来看 StatuBar 的 start() 方法：
@Overridepublic void start() { // 省略部门代码...... // 创建整个SystemUI视图并添加到WindowManager中 createAndAddWindows();//这个重点方法，创建相干的视图 // 省略部门代码...... // Lastly, call to the icon policy to install/update all the icons. mIconPolicy.init(); mSignalPolicy = new StatusBarSignalPolicy(mContext, mIconController); // 省略部门代码......}这里的 mIconPolicy 就是 PhoneStatusBarPolicy对象，mSignalPolicy 就是 StatusBarSignalPolicy 对象。我们这里以 StatusBarSignalPolicy 为例去研究。
StatusBarSignalPolicy实现了NetworkControllerImpl.SignalCallback接口，SignalCallback接口界说在NetworkControllerImpl实现的接口NetworkController中。
// frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/policy/NetworkControllerImpl.java @Inject public NetworkControllerImpl(Context context, @Background Looper bgLooper, DeviceProvisionedController deviceProvisionedController, BroadcastDispatcher broadcastDispatcher, ConnectivityManager connectivityManager, TelephonyManager telephonyManager, WifiManager wifiManager, NetworkScoreManager networkScoreManager) { this(context, connectivityManager, telephonyManager, wifiManager, networkScoreManager, SubscriptionManager.from(context), Config.readConfig(context), bgLooper, new CallbackHandler(), new AccessPointControllerImpl(context), new DataUsageController(context), new SubscriptionDefaults(), deviceProvisionedController, broadcastDispatcher); mReceiverHandler.post(mRegisterListeners); } private final Runnable mRegisterListeners = new Runnable() { @Override public void run() { registerListeners(); } }; void registerListeners() { for (int i = 0; i < mMobileSignalControllers.size(); i++) { MobileSignalController mobileSignalController = mMobileSignalControllers.valueAt(i); mobileSignalController.registerListener(); } if (mSubscriptionListener == null) { mSubscriptionListener = new SubListener(); } mSubscriptionManager.addOnSubscriptionsChangedListener(mSubscriptionListener); mPhone.listen(mPhoneStateListener, LISTEN_ACTIVE_DATA_SUBSCRIPTION_ID_CHANGE); // broadcasts IntentFilter filter = new IntentFilter(); // wifi相干 // wifi信号强度广播 filter.addAction(WifiManager.RSSI_CHANGED_ACTION); // wifi状态变革广播 filter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION); // wifi毗连状态改变 filter.addAction(WifiManager.NETWORK_STATE_CHANGED_ACTION); // 移动网络相干 // SIM卡状态改变 filter.addAction(TelephonyIntents.ACTION_SIM_STATE_CHANGED); // 数据语音订阅修改 filter.addAction(TelephonyIntents.ACTION_DEFAULT_DATA_SUBSCRIPTION_CHANGED); filter.addAction(TelephonyIntents.ACTION_DEFAULT_VOICE_SUBSCRIPTION_CHANGED); filter.addAction(TelephonyIntents.ACTION_SERVICE_STATE_CHANGED); filter.addAction(TelephonyIntents.SPN_STRINGS_UPDATED_ACTION); // 毗连状态相干 // 网络毗连状态发生变革 filter.addAction(ConnectivityManager.CONNECTIVITY_ACTION); // 网络毗连大概不好 filter.addAction(ConnectivityManager.INET_CONDITION_ACTION); // 切换飞行模式时 filter.addAction(Intent.ACTION_AIRPLANE_MODE_CHANGED); filter.addAction(CarrierConfigManager.ACTION_CARRIER_CONFIG_CHANGED); mContext.registerReceiver(this, filter, null, mReceiverHandler); mListening = true; // 省略部门代码...... // 4.更新移动网络控制器 updateMobileControllers(); }在NetworkControllerImpl 的构造方法里，最终会调用到：registerListeners() 方法举行广播的注册。
广播处置惩罚：
@Override public void onReceive(Context context, Intent intent) { if (CHATTY) { Log.d(TAG, "onReceive: intent=" + intent); } final String action = intent.getAction(); switch (action) { case ConnectivityManager.CONNECTIVITY_ACTION: case ConnectivityManager.INET_CONDITION_ACTION: // 省略部门代码...... break; case Intent.ACTION_AIRPLANE_MODE_CHANGED: // 省略部门代码...... break; case TelephonyManager.ACTION_DEFAULT_VOICE_SUBSCRIPTION_CHANGED: // We are using different subs now, we might be able to make calls. // 省略部门代码...... break; case TelephonyManager.ACTION_DEFAULT_DATA_SUBSCRIPTION_CHANGED: // Notify every MobileSignalController so they can know whether they are the // data sim or not. // 省略部门代码...... break; case Intent.ACTION_SIM_STATE_CHANGED: // Avoid rebroadcast because SysUI is direct boot aware. // 省略部门代码...... break; case Intent.ACTION_SERVICE_STATE: // 省略部门代码...... break; case CarrierConfigManager.ACTION_CARRIER_CONFIG_CHANGED: // 省略部门代码...... break; case ImsManager.ACTION_IMS_SERVICE_UP: case ImsManager.ACTION_IMS_SERVICE_DOWN: // 省略部门代码...... break; case ACTION_HIGH_DEF_AUDIO_SUPPORT: // 省略部门代码...... break; case ACTION_MODEM_CHANGE: // 省略部门代码...... break; default: int subId = intent.getIntExtra(SubscriptionManager.EXTRA_SUBSCRIPTION_INDEX, SubscriptionManager.INVALID_SUBSCRIPTION_ID); if (SubscriptionManager.isValidSubscriptionId(subId)) { if (mMobileSignalControllers.indexOfKey(subId) >= 0) { mMobileSignalControllers.get(subId).handleBroadcast(intent); } else { // Can't find this subscription... We must be out of date. updateMobileControllers(); } } else { // wifi状态图标处置惩罚 // No sub id, must be for the wifi. mWifiSignalController.handleBroadcast(intent); } break; } }这里以 wifi状态图标处置惩罚 为例；接下来看WifiSignalController#handleBroadcast():
// frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/policy/WifiSignalController.java public void handleBroadcast(Intent intent) { mWifiTracker.handleBroadcast(intent); mCurrentState.enabled = mWifiTracker.enabled; mCurrentState.connected = mWifiTracker.connected; mCurrentState.ssid = mWifiTracker.ssid; mCurrentState.rssi = mWifiTracker.rssi; mCurrentState.level = mWifiTracker.level; mCurrentState.statusLabel = mWifiTracker.statusLabel; notifyListenersIfNecessary(); }在WifiSignalController#handleBroadcast()方法中，就两个实现，一个是获取 WiFi 的状态，一个是关照更新状态。
我们直接看关照SignalController# notifyListenersIfNecessary() :
// frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/policy/SignalController.java public void notifyListenersIfNecessary() { if (isDirty()) { saveLastState(); // 保持此时的状态 notifyListeners(); // 关照监听器 } } public final void notifyListeners() { notifyListeners(mCallbackHandler); } public abstract void notifyListeners(SignalCallback callback);notifyListener()方法的实如今WifiSignalController类中：
// frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/policy/WifiSignalController.java @Override public void notifyListeners(SignalCallback callback) { // only show wifi in the cluster if connected or if wifi-only boolean visibleWhenEnabled = mContext.getResources().getBoolean( R.bool.config_showWifiIndicatorWhenEnabled); boolean wifiVisible = mCurrentState.enabled && ( (mCurrentState.connected && mCurrentState.inetCondition == 1) || !mHasMobileDataFeature || mWifiTracker.isDefaultNetwork || visibleWhenEnabled); String wifiDesc = mCurrentState.connected ? mCurrentState.ssid : null; boolean ssidPresent = wifiVisible && mCurrentState.ssid != null; String contentDescription = getTextIfExists(getContentDescription()).toString(); if (mCurrentState.inetCondition == 0) { contentDescription += ("," + mContext.getString(R.string.data_connection_no_internet)); } IconState statusIcon = new IconState(wifiVisible, getCurrentIconId(), contentDescription); IconState qsIcon = new IconState(mCurrentState.connected, mWifiTracker.isCaptivePortal ? R.drawable.ic_qs_wifi_disconnected : getQsCurrentIconId(), contentDescription); // callback为 CallbackHandler对象 callback.setWifiIndicators(mCurrentState.enabled, statusIcon, qsIcon, ssidPresent && mCurrentState.activityIn, ssidPresent && mCurrentState.activityOut, wifiDesc, mCurrentState.isTransient, mCurrentState.statusLabel); }可以看到，这里回调了StatusBarSignalPolicy#setWifiIndicators() 方法：
// frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBarSignalPolicy.java @Override public void setWifiIndicators(boolean enabled, IconState statusIcon, IconState qsIcon, boolean activityIn, boolean activityOut, String description, boolean isTransient, String statusLabel) { boolean visible = statusIcon.visible && !mBlockWifi; boolean in = activityIn && mActivityEnabled && visible; boolean out = activityOut && mActivityEnabled && visible; WifiIconState newState = mWifiIconState.copy(); newState.visible = visible; newState.resId = statusIcon.icon; newState.activityIn = in; newState.activityOut = out; newState.slot = mSlotWifi; newState.airplaneSpacerVisible = mIsAirplaneMode; newState.contentDescription = statusIcon.contentDescription; MobileIconState first = getFirstMobileState(); newState.signalSpacerVisible = first != null && first.typeId != 0; updateWifiIconWithState(newState); mWifiIconState = newState; } private void updateWifiIconWithState(WifiIconState state) { if (state.visible && state.resId > 0) { mIconController.setSignalIcon(mSlotWifi, state); mIconController.setIconVisibility(mSlotWifi, true); } else { mIconController.setIconVisibility(mSlotWifi, false); } }通过StatusBarIconController接口设置图标的套路都是一样的:
- 获取图标名字
- 监听变乱
- 通过StatusBarIconControllerImpl相应的方法设置图标。
接下来再看StatusBarIconControllerImpl#setSignalIcon()：
/** * Signal icons need to be handled differently, because they can be * composite views */ @Override public void setSignalIcon(String slot, WifiIconState state) { int index = getSlotIndex(slot); if (state == null) { removeIcon(index, 0); return; } StatusBarIconHolder holder = getIcon(index, 0); if (holder == null) { holder = StatusBarIconHolder.fromWifiIconState(state); setIcon(index, holder); } else { holder.setWifiState(state); handleSet(index, holder); } }起首设置WiFi的状态信息，遍历mIconGroups分别实验StatusBarIconController接口中静态类IconManager中的onIconAdded()和onSetIconHolder()的回调。
IconManager用于将信息从StatusBarIconController转换为ViewGroup中的ImageViews(com.android.systemui.statusbar.AlphaOptimizedImageView)。
接着看IconManager中的onIconAdded()和onSetIconHolder()方法：这两个方法一个用于添加、一个用于更新。
public interface StatusBarIconController { .... public static class DarkIconManager extends IconManager { .... public DarkIconManager(LinearLayout linearLayout) { // 将布局传入IconManager super(linearLayout); mIconHPadding = mContext.getResources().getDimensionPixelSize( R.dimen.status_bar_icon_padding); mDarkIconDispatcher = Dependency.get(DarkIconDispatcher.class); } .... @Override protected void onIconAdded(int index, String slot, boolean blocked, StatusBarIconHolder holder) { // 调用到父类的addHolder方法 StatusIconDisplayable view = addHolder(index, slot, blocked, holder); .... } } public static class IconManager implements DemoMode { .... protected final ViewGroup mGroup; protected final Context mContext; public IconManager(ViewGroup group) { mGroup = group; mContext = group.getContext(); mIconSize = mContext.getResources().getDimensionPixelSize( R.dimen.status_bar_height); .... } .... protected StatusIconDisplayable addHolder(int index, String slot, boolean blocked, StatusBarIconHolder holder) { switch (holder.getType()) { case TYPE_ICON: return addIcon(index, slot, blocked, holder.getIcon()); case TYPE_WIFI: return addSignalIcon(index, slot, holder.getWifiState()); case TYPE_MOBILE: return addMobileIcon(index, slot, holder.getMobileState()); } return null; } @VisibleForTesting protected StatusBarWifiView addSignalIcon(int index, String slot, WifiIconState state) { // 创建一个StatusBarWifiView StatusBarWifiView view = onCreateStatusBarWifiView(slot); view.applyWifiState(state); // 将view 添加进ViewGroup mGroup.addView(view, index, onCreateLayoutParams()); if (mIsInDemoMode) { mDemoStatusIcons.addDemoWifiView(state); } return view; } private StatusBarWifiView onCreateStatusBarWifiView(String slot) { StatusBarWifiView view = StatusBarWifiView.fromContext(mContext, slot); return view; } .... public void onSetIconHolder(int viewIndex, StatusBarIconHolder holder) { switch (holder.getType()) { case TYPE_ICON: onSetIcon(viewIndex, holder.getIcon()); return; case TYPE_WIFI: onSetSignalIcon(viewIndex, holder.getWifiState()); return; case TYPE_MOBILE: onSetMobileIcon(viewIndex, holder.getMobileState()); default: break; } } public void onSetSignalIcon(int viewIndex, WifiIconState state) { StatusBarWifiView wifiView = (StatusBarWifiView) mGroup.getChildAt(viewIndex); if (wifiView != null) { wifiView.applyWifiState(state); } if (mIsInDemoMode) { mDemoStatusIcons.updateWifiState(state); } } .... } }这里根据差异的StatusBarIconHolder范例，设置差异的网络Icon，上面列出了 Wifi 图标相干的方法。
SystemUI状态栏图标根据源码可大要分为三种：
1. StatusBarIconView
2. StatusBarWifiView
3. StatusBarMobileView
这里告急以Wifi 相干图标（StatusBarWifiView）举行分析，添加Icon时起首会创建一个
StatusBarWifiView，然后调用StatusBarWifiView的applyWifiState更新其表现状态，末了将其加入到CollapsedStatusBarFragment中放置Icon的ViewGroup中，如许就完成了添加过程；
再来看看 CollapsedStatusBarFragment：
// SystemUI/src/com/android/systemui/statusbar/phone/CollapsedStatusBarFragment.javapublic class CollapsedStatusBarFragment extends Fragment implements CommandQueue.Callbacks { .... private DarkIconManager mDarkIconManager; .... @Override public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) { return inflater.inflate(R.layout.status_bar, container, false); } @Override public void onViewCreated(View view, @Nullable Bundle savedInstanceState) { .... // 这里可以看出status_bar布局中的statusIcons就是我们展示各种Icon的地域 mDarkIconManager = new DarkIconManager(view.findViewById(R.id.statusIcons)); mDarkIconManager.setShouldLog(true); Dependency.get(StatusBarIconController.class).addIconGroup(mDarkIconManager); .... }}增补：
notifyListenersIfNecessary()在其父类SignalController中界说，
// SignalController.java private final CallbackHandler mCallbackHandler; public void notifyListenersIfNecessary() { if (isDirty()) { saveLastState(); notifyListeners(); } } // 在这里留意了，在这里的的参数是 CallbackHandler 的对象 public final void notifyListeners() { notifyListeners(mCallbackHandler); }// callback 则是 CallbackHandler 的对象。 public abstract void notifyListeners(SignalCallback callback); CallbackHandler维护了全部须要监听的SignalCallback接口对象,我们的StatusBarSignalPolicy就实现了该接口。
StatusBarSignalPolicy告急实验网络图标的革新动作，着实现了NetworkControllerImpl.SignalCallback接口,然后注册到NetworkController,其具体实现类NetworkControllerImpl会根据WIFI,SIM等状态广播来进一步派发给具体的Controller,比方WifiSignalController,每个Controller只与CallbackHandler交互,然后CallbackHandler继承转交给维护的SignalCallback接口的具体实现类,比方StatusBarSignalPolicy |
