1、BluetoothEnabler的构造函数public BluetoothEnabler(Context context,Switch switch_) {mContext = context;mSwitch = switch_;//很简单了，去调用一个LocalBluetoothManager类的getInstance，其实会构造该类的
 LocalBluetoothManager manager =LocalBluetoothManager.getInstance(context);if (manager == null) {// Bluetooth is not supported
 mLocalAdapter = null;mSwitch.setEnabled(false);} else {//构造成功后，通过manager得到bluetooth的adapter
 mLocalAdapter =manager.getBluetoothAdapter();}//同时新建一个intent，用于接收ACTION_STATE_CHANGED
 mIntentFilter = newIntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED);}2、LocalBluetoothManager类的getInstancepublic static synchronizedLocalBluetoothManager getInstance(Context context) {if (sInstance == null) {//2.1同样的，这个会去调用LocalBluetoothAdapter的getInstance，也会构造该类
 LocalBluetoothAdapter adapter =LocalBluetoothAdapter.getInstance();if (adapter == null) {return null;}// This will be around as long asthis process is
 Context appContext =context.getApplicationContext();//2.2构造LocalBluetoothManager类
 sInstance = newLocalBluetoothManager(adapter, appContext);}return sInstance;}2.1LocalBluetoothAdapter的getInstancestatic synchronized LocalBluetoothAdaptergetInstance() {if (sInstance == null) {//2.1.1通过BluetoothAdapter得到DefaultAdapter
 BluetoothAdapter adapter =BluetoothAdapter.getDefaultAdapter();if (adapter != null) {//2.1.2若有该DefaultAdapter，则构造LocalBluetoothAdapter
 sInstance = newLocalBluetoothAdapter(adapter);}}return sInstance;}2.1.1BluetoothAdapter得到DefaultAdapterpublic static synchronized BluetoothAdaptergetDefaultAdapter() {if (sAdapter == null) {IBinder b =ServiceManager.getService(BluetoothAdapter.BLUETOOTH_SERVICE);if (b != null) {IBluetooth service =IBluetooth.Stub.asInterface(b);sAdapter = newBluetoothAdapter(service);}}return sAdapter;}2.1.2构造LocalBluetoothAdapter//其实就是 mAdapter的初始化而已
 privateLocalBluetoothAdapter(BluetoothAdapter adapter) {mAdapter = adapter;}2.2构造LocalBluetoothManager类//管理本地蓝牙类，用来在蓝牙API子类上面再封装一个接口
 privateLocalBluetoothManager(LocalBluetoothAdapter adapter, Context context) {mContext = context;//mLocalAdapter初始化为DefaultAdapter中得到的值
 
mLocalAdapter= adapter;//构造CachedBluetoothDeviceManager，用来管理远程蓝牙设备
 mCachedDeviceManager = newCachedBluetoothDeviceManager(context);//2.2.1构建BluetoothEventManager，该类是用来管理广播消息和回调函数的，即分发不同的消息去对UI进行处理
 mEventManager = newBluetoothEventManager(mLocalAdapter,mCachedDeviceManager, context);//2.2.2该类提供对不同LocalBluetoothProfile object的访问
 mProfileManager = newLocalBluetoothProfileManager(context,mLocalAdapter,mCachedDeviceManager, mEventManager);}2.2.1构建BluetoothEventManagerBluetoothEventManager(LocalBluetoothAdapteradapter,CachedBluetoothDeviceManagerdeviceManager, Context context) {mLocalAdapter = adapter;mDeviceManager = deviceManager;//创建两个IntentFilter
 mAdapterIntentFilter = newIntentFilter();//这里没有对mProfileIntentFilter进行初始化，这个在LocalBluetoothProfileManager的addProfile中实现
 mProfileIntentFilter = newIntentFilter();//创建一个Handler的Hash表
 mHandlerMap = new HashMap<String,Handler>();mContext = context;//注册对adapter和Device的几个广播消息的处理回调函数//add action到mAdapterIntentFilter// Bluetooth on/off broadcasts
 addHandler(BluetoothAdapter.ACTION_STATE_CHANGED, newAdapterStateChangedHandler());// Discovery broadcasts
 addHandler(BluetoothAdapter.ACTION_DISCOVERY_STARTED, newScanningStateChangedHandler(true));addHandler(BluetoothAdapter.ACTION_DISCOVERY_FINISHED, newScanningStateChangedHandler(false));addHandler(BluetoothDevice.ACTION_FOUND, new DeviceFoundHandler());addHandler(BluetoothDevice.ACTION_DISAPPEARED, newDeviceDisappearedHandler());addHandler(BluetoothDevice.ACTION_NAME_CHANGED, newNameChangedHandler());// Pairing broadcasts
 addHandler(BluetoothDevice.ACTION_BOND_STATE_CHANGED, newBondStateChangedHandler());addHandler(BluetoothDevice.ACTION_PAIRING_CANCEL, newPairingCancelHandler());// Fine-grained state broadcasts
 addHandler(BluetoothDevice.ACTION_CLASS_CHANGED, newClassChangedHandler());addHandler(BluetoothDevice.ACTION_UUID,new UuidChangedHandler());// Dock event broadcasts
 addHandler(Intent.ACTION_DOCK_EVENT,new DockEventHandler());//mAdapterIntentFilter的接收处理函数
 mContext.registerReceiver(mBroadcastReceiver, mAdapterIntentFilter);}2.2.2构造LocalBluetoothProfileManager类LocalBluetoothProfileManager(Contextcontext,LocalBluetoothAdapter adapter,CachedBluetoothDeviceManagerdeviceManager,BluetoothEventManager eventManager){mContext = context;//各个类之间进行关联
 mLocalAdapter = adapter;mDeviceManager = deviceManager;mEventManager = eventManager;// pass this reference to adapter andevent manager (circular dependency)
 mLocalAdapter.setProfileManager(this);mEventManager.setProfileManager(this);ParcelUuid[] uuids =adapter.getUuids();// uuids may be null if Bluetooth isturned offif (uuids != null) {//假如已经有了uuid，根据uuid来add并new对应的profile，只针对A2DP,HFP,HSP,OPP四个profile，HID和PAN在下面，每次都add
 updateLocalProfiles(uuids);}// Always add HID and PAN profiles//加入HID和PAN两个profile
 mHidProfile = new HidProfile(context,mLocalAdapter);addProfile(mHidProfile,HidProfile.NAME,BluetoothInputDevice.ACTION_CONNECTION_STATE_CHANGED);mPanProfile = new PanProfile(context);addPanProfile(mPanProfile,PanProfile.NAME,BluetoothPan.ACTION_CONNECTION_STATE_CHANGED);Log.d(TAG,"LocalBluetoothProfileManager construction complete");}好吧，其实我们被骗了，刚刚只是一个路引，不是真正的操作，真正的操作向来都是从你滑动界面那个on/off键开始的，因此我们决定把这个键的处理给揪出来。在Settings界面上一共就只有两个on/off键，一个是wifi，另一个就是蓝牙了，我们从这个代码入手：case HEADER_TYPE_SWITCH://其实写这个代码的人也比较心虚，假如switch多一点，下面就要重写了// Would need a differenttreatment if the main menu had more switchesif (header.id ==R.id.wifi_settings) {mWifiEnabler.setSwitch(holder.switch_);} else {//这个就是处理了，上面的路引没有白做啊
 mBluetoothEnabler.setSwitch(holder.switch_);}3、mBluetoothEnabler.setSwitch分析public void setSwitch(Switch switch_) {//若是和上次相同，则不做任何事情，可以理解，代码也懒嘛if (mSwitch == switch_) return;//把上次的switch的changelistener清空
 mSwitch.setOnCheckedChangeListener(null);mSwitch = switch_;//重设这次的switch的changelistener
 mSwitch.setOnCheckedChangeListener(this);int bluetoothState =BluetoothAdapter.STATE_OFF;//获取getBluetoothState，这个过程也会同步一下state，防止改变if (mLocalAdapter != null)bluetoothState = mLocalAdapter.getBluetoothState();//根据状态设置一下两个标志位boolean isOn = bluetoothState ==BluetoothAdapter.STATE_ON;boolean isOff = bluetoothState ==BluetoothAdapter.STATE_OFF;//设置checked的状态位。注意，假如这里状态发生了改变，则会调用this.onCheckedChanged来进行处理
 mSwitch.setChecked(isOn);if(WirelessSettings.isRadioAllowed(mContext, Settings.System.RADIO_BLUETOOTH)) {//有bluetooth或者不是airplane，则该switch不变灰，否则，灰的。
 mSwitch.setEnabled(isOn || isOff);} else {mSwitch.setEnabled(false);}}4、onCheckedChanged在switch状态发生改变后，会调用这个地方的回调函数进行处理。public void onCheckedChanged(CompoundButtonbuttonView, boolean isChecked) {// Show toast message if Bluetooth isnot allowed in airplane mode//若是打开的话，就需要检查一下是否allow Bluetooth（radio，airplane的check）if (isChecked &&!WirelessSettings.isRadioAllowed(mContext,Settings.System.RADIO_BLUETOOTH)) {Toast.makeText(mContext,R.string.wifi_in_airplane_mode, Toast.LENGTH_SHORT).show();// Reset switch to off//若是不对的话，reset为off
 buttonView.setChecked(false);}if (mLocalAdapter != null) {//4.1设置scanmode，放心，它会判断state的，不是STATE_ON，会直接返回false的
 mLocalAdapter.setScanMode(BluetoothAdapter.SCAN_MODE_CONNECTABLE);//4.2使能或不使能Bluetooth了
 mLocalAdapter.setBluetoothEnabled(isChecked);}//过程中还是会反灰，直到setBluetoothEnabled的结果返回会改变switch的状态
 mSwitch.setEnabled(false);}4.1设置scanmod会调用adapter中的setScanMode，直接去看就可以了，事实上就是设置了两个property标志，没什么public boolean setScanMode(int mode) {//这里把这个代码写出来就是证明一下，STATE_ON才会真正做下去，否则免谈if (getState() != STATE_ON) returnfalse;//这里会调用对应server中的setScanModereturn setScanMode(mode, 120);}public synchronized boolean setScanMode(intmode, int duration) {//这里有个permission，好像和2.3中不一样，注意一下     mContext.enforceCallingOrSelfPermission(android.Manifest.permission.WRITE_SECURE_SETTINGS,"NeedWRITE_SECURE_SETTINGS permission");boolean pairable;boolean discoverable;switch (mode) {case BluetoothAdapter.SCAN_MODE_NONE:pairable = false;discoverable = false;break;caseBluetoothAdapter.SCAN_MODE_CONNECTABLE://开始就是这里了，可pairable，但是不可discoverable
 pairable = true;discoverable = false;break;caseBluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE:pairable = true;discoverable = true;if (DBG) Log.d(TAG, "BTDiscoverable for " + duration + " seconds");break;default:Log.w(TAG, "Requested invalidscan mode " + mode);return false;}//设置这两个property标志
 setPropertyBoolean("Discoverable", discoverable);setPropertyBoolean("Pairable", pairable);return true;}4.2setBluetoothEnabled分析public void setBluetoothEnabled(booleanenabled) {//根据enabled的标志设置是enable还是disable，在2.3中，这个地方就是bt_enable哦，这里还不知道，我们在第5步进行详细的分析boolean success = enabled? mAdapter.enable(): mAdapter.disable();//成功了，设置对应的状态位if (success) {setBluetoothStateInt(enabled?BluetoothAdapter.STATE_TURNING_ON:BluetoothAdapter.STATE_TURNING_OFF);} else {if (Utils.V) {Log.v(TAG,"setBluetoothEnabled call, manager didn't return " +"success forenabled: " + enabled);}//同步一下设置的状态
 syncBluetoothState();}}}5、mAdapter.enable或者mAdapter.disable就先分析enable吧，它会调用对应server端的enable(ture),我们来看看源码public synchronized boolean enable(booleansaveSetting) {mContext.enforceCallingOrSelfPermission(BLUETOOTH_ADMIN_PERM,"Need BLUETOOTH_ADMIN permission");// Airplane mode can prevent Bluetoothradio from being turned on.//检查是否是飞行模式if (mIsAirplaneSensitive &&isAirplaneModeOn() && !mIsAirplaneToggleable) {return false;}//5.1注意与2.3的不同，在2.3中，这里会调用enablethread去调用native的bt_enable，而4.0没有这么做。没事，我们来分析4.0怎么做的。
 mBluetoothState.sendMessage(BluetoothAdapterStateMachine.USER_TURN_ON,saveSetting);return true;}5.1mBluetoothState.sendMessage简单理解一下，mBluetoothState是BluetoothAdapterStateMachine类。因此，在分析的之前，简单说一下，它其实就是类似一个状态转换图，根据你所处于的状态，然后再判断收到的操作，进行不同的处理。根据构造函数中的setInitialState(mPowerOff);可以知道初始状态是PowerOff。但是从它给出的状态机可以看出，在PowerOff的状态时，它是通过TURN_HOT/TURN_ON来改变到HotOff状态的，然后才会收到USER_TURN_ON，去该变到BluetootOn的状态。因此，可以肯定的是我们这里的USER_TURN_ON不是它收到的第一个message，因此我们去纠结一下它是从哪里开始改变PowerOff的状态：extra1，然后再来看这里的处理吧：5.2。extra1、mAdapter.enable之前的状态机转变众所周知，android在启动之后会启动一个serverThread的线程，通过这个线程会启动一系列的服务。我们的蓝牙服务也是在这里启动的，android4.0其实在这个地方对状态机进行了修改，我们来看一下源码：该代码位于framworks/base/services/java/com/android/server/systemserver.javaBluetoothServicebluetooth = null;BluetoothA2dpServicebluetoothA2dp = null;//模拟器上是不支持Bluetooth的，工厂测试模式也没有Bluetooth（这个不了解）// Skip Bluetooth if we have anemulator kernel// TODO: Use a more reliable checkto see if this product should// support Bluetooth - see bug988521if(SystemProperties.get("ro.kernel.qemu").equals("1")) {Slog.i(TAG, "No BluetoohService (emulator)");} else if (factoryTest ==SystemServer.FACTORY_TEST_LOW_LEVEL) {Slog.i(TAG, "No BluetoothService (factory test)");} else {Slog.i(TAG, "BluetoothService");//新建Bluetoothservice，并把他加入到ServiceManager中
 bluetooth = newBluetoothService(context);ServiceManager.addService(BluetoothAdapter.BLUETOOTH_SERVICE,bluetooth);//extra1.1在启动Bluetooth服务后进行一些初始化，呵呵，这里就对状态机进行了改变
 bluetooth.initAfterRegistration();//新建了BluetoothA2dpService，并把之加入到了ServiceManager中
 
bluetoothA2dp= new BluetoothA2dpService(context, bluetooth);ServiceManager.addService(BluetoothA2dpService.BLUETOOTH_A2DP_SERVICE,bluetoothA2dp);//extra1.2同样的要在之后做些init的工作
 bluetooth.initAfterA2dpRegistration();//得到是否飞行int airplaneModeOn =Settings.System.getInt(mContentResolver,Settings.System.AIRPLANE_MODE_ON, 0);//看Bluetooth是否on，若是打开的状态（没有飞行），则这里会调用enable去打开int bluetoothOn =Settings.Secure.getInt(mContentResolver,Settings.Secure.BLUETOOTH_ON, 0);if (airplaneModeOn == 0&& bluetoothOn != 0) {bluetooth.enable();}}extra1.1initAfterRegistration分析public synchronized voidinitAfterRegistration() {//得到default的adapter
 mAdapter =BluetoothAdapter.getDefaultAdapter();//创建BluetoothAdapterStateMachine，初始化几个状态，并设初始状态位POWEROFF,这里同时新建了一个EventLoop
 mBluetoothState = newBluetoothAdapterStateMachine(mContext, this, mAdapter);mBluetoothState.start();//根据这个xml的bool变量来决定是否先期TURN_HOT，该变量位于frameworks/base/core/res/res/values/config.xml中，默认为trueif (mContext.getResources().getBoolean(com.android.internal.R.bool.config_bluetooth_adapter_quick_switch)) {//extra1.2发送TURN_HOT的状态变化message
 mBluetoothState.sendMessage(BluetoothAdapterStateMachine.TURN_HOT);}//得到对应的EventLoop
 mEventLoop =mBluetoothState.getBluetoothEventLoop();}extra1.2  TURN_HOT message的处理/*** Bluetooth module's power is off,firmware is not loaded.*/private class PowerOff extends State {@Overridepublic void enter() {if (DBG) log("Enter PowerOff:" + getCurrentMessage().what);}@Overridepublic boolean processMessage(Messagemessage) {log("PowerOff process message:" + message.what);boolean retValue = HANDLED;switch(message.what) {……case TURN_HOT://extra1.3这里就是我们寻找了千年的bt_enable所在的地方。我们去看看if (prepareBluetooth()) {//extra1.5转变状态到warmup，在prepareBluetooth真正完成后，这个状态还会发生改变
 transitionTo(mWarmUp);}break;……extra1.3prepareBluetooth分析看英文注释就知道了，不解释/*** Turn on Bluetooth Module, Loadfirmware, and do all the preparation* needed to get the Bluetooth Moduleready but keep it not discoverable* and not connectable.* The last step of this method sets upthe local service record DB.* There will be a event reporting thestatus of the SDP setup.*/private boolean prepareBluetooth() {//extra1.4首先还是调用了enableNative的本地方法，到这里你会发现终于和2.3相似了（不过请注意调用的时机不同了，这个在初始化，而2.3在界面的on/off滑动的时候），它还是会调用bt_enable，这个就会调用对应的set_bluetooth_power了if(mBluetoothService.enableNative() != 0) {return false;}// try to start event loop, give 2attempts//尝试两次去start event loopint retryCount = 2;boolean eventLoopStarted = false;while ((retryCount-- > 0)&& !eventLoopStarted) {mEventLoop.start();// it may take a moment for theother thread to do its// thing.  Check periodically for a while.int pollCount = 5;while ((pollCount-- > 0)&& !eventLoopStarted) {if(mEventLoop.isEventLoopRunning()) {eventLoopStarted =true;break;}try {Thread.sleep(100);} catch(InterruptedException e) {log("prepareBluetooth sleep interrupted: " + pollCount);break;}}}//出错处理if (!eventLoopStarted) {mBluetoothService.disableNative();return false;}// get BluetoothService ready//建立native data以及SDP相关的一些操作，这里将会产生PropertyChanged的UUIDs的signal，对该信号的处理会对状态发生改变，详细分析见extra1.5if(!mBluetoothService.prepareBluetooth()) {mEventLoop.stop();mBluetoothService.disableNative();return false;}//设置一个prepare的超时处理，在该时间内没有收到UUID changed的signal将会进行错误处理
 sendMessageDelayed(PREPARE_BLUETOOTH_TIMEOUT,PREPARE_BLUETOOTH_TIMEOUT_TIME);return true;}}extra1.4bt_enable分析intbt_enable() {LOGV(__FUNCTION__);int ret = -1;int hci_sock = -1;int attempt;//power的设置，on。不解释，可加入对应板子的gpio口的处理，默认就只用了rfkill的处理if (set_bluetooth_power(1) < 0) gotoout;//开始hciattach服务，这个我们也做了修改，加入了rtk_h5
 LOGI("Starting hciattachdaemon");if (property_set("ctl.start","hciattach") < 0) {LOGE("Failed to starthciattach");set_bluetooth_power(0);goto out;}// Try for 10 seconds, this can onlysucceed once hciattach has sent the// firmware and then turned on hci devicevia HCIUARTSETPROTO ioctlfor (attempt = 1000; attempt > 0;  attempt--) {//创建hci_sock
 hci_sock = create_hci_sock();if (hci_sock < 0) goto out;//调用ioctl的HCIDEVUP，来判断hciattach是否已经ok了。
 ret = ioctl(hci_sock, HCIDEVUP,HCI_DEV_ID);LOGI("bt_enable: ret: %d, errno:%d", ret, errno);if (!ret) {break;} else if (errno == EALREADY) {LOGW("Bluetoothd alreadystarted, unexpectedly!");break;}close(hci_sock);//等待10 ms后再试一次
 usleep(100000);  // 100 ms retry delay
 }//10s都没有搞定，需要做个失败的处理if (attempt == 0) {LOGE("%s: Timeout waiting for HCIdevice to come up, error- %d, ",__FUNCTION__, ret);if (property_set("ctl.stop","hciattach") < 0) {LOGE("Error stoppinghciattach");}set_bluetooth_power(0);goto out;}//启动bluetoothd服务
 LOGI("Starting bluetoothddeamon");if (property_set("ctl.start","bluetoothd") < 0) {LOGE("Failed to startbluetoothd");set_bluetooth_power(0);goto out;}ret = 0;out://关闭hci_sockif (hci_sock >= 0) close(hci_sock);return ret;}extra 1.5 PropetyChanged的UUIDs的处理event_filter是用来对bluez的dbus的signal进行监听的，有signal产生后，会在这里进行处理。因此，我们直接到这里看看该怎么处理。//Called by dbus during WaitForAndDispatchEventNative()
 
staticDBusHandlerResult event_filter(DBusConnection *conn, DBusMessage *msg,void*data) {native_data_t *nat;JNIEnv *env;DBusError err;DBusHandlerResult ret;//err的一个初始化
 dbus_error_init(&err);//得到参数
 nat = (native_data_t *)data;nat->vm->GetEnv((void**)&env,nat->envVer);if (dbus_message_get_type(msg) !=DBUS_MESSAGE_TYPE_SIGNAL) {LOGV("%s: not interested (not asignal).", __FUNCTION__);returnDBUS_HANDLER_RESULT_NOT_YET_HANDLED;}LOGV("%s: Received signal %s:%s from%s", __FUNCTION__,dbus_message_get_interface(msg),dbus_message_get_member(msg),dbus_message_get_path(msg));env->PushLocalFrame(EVENT_LOOP_REFS);……//PropertyChanged这个signal的处理
 } else if (dbus_message_is_signal(msg,"org.bluez.Adapter","PropertyChanged")) {//由msg解析参数
 jobjectArray str_array =parse_adapter_property_change(env, msg);if (str_array != NULL) {/* Check if bluetoothd has(re)started, if so update the path. */jstring property =(jstring)env->GetObjectArrayElement(str_array, 0);const char *c_property =env->GetStringUTFChars(property, NULL);//检查Property是否startedif (!strncmp(c_property,"Powered", strlen("Powered"))) {//若是powered，则看value是否是true，是ture就得到对应的path
 jstring value =(jstring)env->GetObjectArrayElement(str_array, 1);const char *c_value =env->GetStringUTFChars(value, NULL);if (!strncmp(c_value,"true", strlen("true")))nat->adapter =get_adapter_path(nat->conn);env->ReleaseStringUTFChars(value, c_value);}env->ReleaseStringUTFChars(property, c_property);//extra1.6调用对应的method_onPropertyChanged函数，该method对应的onPropertyChanged函数
 env->CallVoidMethod(nat->me,method_onPropertyChanged,str_array);} elseLOG_AND_FREE_DBUS_ERROR_WITH_MSG(&err, msg);goto success;……extra1.6真正的处理函数onPropertyChanged分析/*** Called by native code on aPropertyChanged signal from* org.bluez.Adapter. This method is alsocalled from* {@link BluetoothAdapterStateMachine} toset the "Pairable"* property when Bluetooth is enabled.** @param propValues a string arraycontaining the key and one or more* values.*//*package*/ void onPropertyChanged(String[]propValues) {BluetoothAdapterPropertiesadapterProperties =mBluetoothService.getAdapterProperties();//先fill up cacheif (adapterProperties.isEmpty()) {// We have got a property changebefore// we filled up our cache.
 adapterProperties.getAllProperties();}log("Property Changed: " +propValues[0] + " : " + propValues[1]);String name = propValues[0];……//对UUIDs的处理
 } else if(name.equals("Devices") || name.equals("UUIDs")) {String value = null;int len =Integer.valueOf(propValues[1]);if (len > 0) {StringBuilder str = newStringBuilder();for (int i = 2; i <propValues.length; i++) {str.append(propValues[i]);str.append(",");}value = str.toString();}//把name和value值加入到property的map中
 adapterProperties.setProperty(name,value);//extra1.7有UUIDs的change signal会刷新Bluetooth的Stateif (name.equals("UUIDs")){mBluetoothService.updateBluetoothState(value);}//对Pairable和Discoverable的处理
 } else if(name.equals("Pairable") || name.equals("Discoverable")) {adapterProperties.setProperty(name,propValues[1]);if(name.equals("Discoverable")) {//5.6发送SCAN_MODE_CHANGED的msg，去改变状态机      mBluetoothState.sendMessage(BluetoothAdapterStateMachine.SCAN_MODE_CHANGED);
 }//设置对应的property
 String pairable =name.equals("Pairable") ? propValues[1] :adapterProperties.getProperty("Pairable");String discoverable =name.equals("Discoverable") ? propValues[1] :adapterProperties.getProperty("Discoverable");// This shouldn't happen, unlessAdapter Properties are null.if (pairable == null ||discoverable == null)return;int mode =BluetoothService.bluezStringToScanMode(pairable.equals("true"),discoverable.equals("true"));if (mode >= 0) {//当pairable和discoverable均为true的时候，会发送一个ACTION_SCAN_MODE_CHANGED的广播消息
 Intent intent = newIntent(BluetoothAdapter.ACTION_SCAN_MODE_CHANGED);intent.putExtra(BluetoothAdapter.EXTRA_SCAN_MODE, mode);intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);mContext.sendBroadcast(intent,BLUETOOTH_PERM);}}……extra1.7  UUIDs改变带来的State的刷新/*** This function is called from BluetoothEvent Loop when onPropertyChanged* for adapter comes in with UUID property.* @param uuidsThe uuids of adapter asreported by Bluez.*//*package*/ synchronized voidupdateBluetoothState(String uuids) {ParcelUuid[] adapterUuids =convertStringToParcelUuid(uuids);//为什么必须包含所有已经有的uuid？？感觉有点反了，再看看if (mAdapterUuids != null &&BluetoothUuid.containsAllUuids(adapterUuids, mAdapterUuids)) {//放SERVICE_RECORD_LOADED的信息，此时，处于warm up状态，看extra1.8分析状态如何继续改变          mBluetoothState.sendMessage(BluetoothAdapterStateMachine.SERVICE_RECORD_LOADED);
 }}extra1.8 UUIDs对状态机改变/*** Turning on Bluetooth module's power,loading firmware, starting* event loop thread to listen on Bluetoothmodule event changes.*/private class WarmUp extends State {@Overridepublic void enter() {if (DBG) log("Enter WarmUp:" + getCurrentMessage().what);}@Overridepublic boolean processMessage(Messagemessage) {log("WarmUp process message:" + message.what);boolean retValue = HANDLED;switch(message.what) {case SERVICE_RECORD_LOADED://可以看到，首先会把当时从poweroff过来的一个超时message拿remove了。
 removeMessages(PREPARE_BLUETOOTH_TIMEOUT);//转到hotoff状态，在hotoff状态仍会接收到多个SERVICE_RECORD_LOADED的msg，但是那个状态下该msg将没有任何handled，因此会一直处于hotoff状态
 transitionTo(mHotOff);break;……5.2mAdapter.enable中mBluetoothState.sendMessage后的状态机处理由extra的分析可知，此时，Bluetooth的State已经处于HotOff状态了，所以，从这里开始处理State的变换。/*** Bluetooth Module has powered, firmwareloaded, event loop started,* SDP loaded, but the modules staysnon-discoverable and* non-connectable.*/private class HotOff extends State {@Overridepublic void enter() {if (DBG) log("Enter HotOff:" + getCurrentMessage().what);}@Overridepublic boolean processMessage(Messagemessage) {log("HotOff process message:" + message.what);boolean retValue = HANDLED;switch(message.what) {case USER_TURN_ON://发出BluetoothAdapter.STATE_TURNING_ON的广播消息
 broadcastState(BluetoothAdapter.STATE_TURNING_ON);if ((Boolean) message.obj){//就是把Settings.Secure.BLUETOOTH_ON设为1。用于标志Bluetooth enable了
 persistSwitchSetting(true);}// let it fall toTURN_ON_CONTINUE://$FALL-THROUGH$//注意上面没有break哦case TURN_ON_CONTINUE://这里就是把Bluetooth设为connectable就是Powered=1，这里就把prepareBluetooth中设置的不可连接重新设置回来了。这个重连会产生一些新的变化，它会发送WRITE_SCAN_ENABLE的cmd，因此在该cmd_complete时会有一些新的处理：5.3，它会再次引起状态机的改变：5.6
 mBluetoothService.switchConnectable(true);//进入到Switching状态
 transitionTo(mSwitching);break;……5.3 WRITE_SCAN_ENABLE在cmd_complete后的处理在bluez中是用cmd_complete函数来监视发出cmd完成后的处理的。该函数具体如下：staticinline void cmd_complete(int index, void *ptr){structdev_info *dev = &devs[index];evt_cmd_complete*evt = ptr;uint16_topcode = btohs(evt->opcode);uint8_tstatus = *((uint8_t *) ptr + EVT_CMD_COMPLETE_SIZE);switch(opcode) {……//WRITE_SCAN_ENABLE命令完成的处理函数，会再发一个READ_SCAN_ENABLE的命令
 
casecmd_opcode_pack(OGF_HOST_CTL, OCF_WRITE_SCAN_ENABLE):hci_send_cmd(dev->sk,OGF_HOST_CTL, OCF_READ_SCAN_ENABLE,0,NULL);break;//5.4紧接着就是对READ_SCAN_ENABLE命令完成的处理，它是通过read_scan_complete来实现的
 
casecmd_opcode_pack(OGF_HOST_CTL, OCF_READ_SCAN_ENABLE):ptr+= sizeof(evt_cmd_complete);read_scan_complete(index,status, ptr);break;……}5.4 read_scan命令完成的处理staticvoid read_scan_complete(int index, uint8_t status, void *ptr){structbtd_adapter *adapter;read_scan_enable_rp*rp = ptr;DBG("hci%dstatus %u", index, status);//由index得到对应的adapter
 
adapter= manager_find_adapter_by_id(index);if(!adapter) {error("Unableto find matching adapter");return;}//5.5这里算是一个通知adapter，mode改变了。
 
adapter_mode_changed(adapter,rp->enable);}5.5通知adapter，mode发生了改变voidadapter_mode_changed(struct btd_adapter *adapter, uint8_t scan_mode){constgchar *path = adapter_get_path(adapter);gbooleandiscoverable, pairable;DBG("old0x%02x new 0x%02x", adapter->scan_mode, scan_mode);//若相同，则nothing todoif(adapter->scan_mode == scan_mode){#ifdefBOARD_HAVE_BLUETOOTH_BCM/*we may reset scan_mode already inbtd_adapter_stop(), so comes to here*/set_mode_complete(adapter);#endifreturn;}//把discoverable的timeout清空
 
adapter_remove_discov_timeout(adapter);//这里开始，是设为SCAN_PAGE| SCAN_INQUIRYswitch(scan_mode) {caseSCAN_DISABLED:adapter->mode= MODE_OFF;discoverable= FALSE;pairable= FALSE;break;caseSCAN_PAGE:adapter->mode= MODE_CONNECTABLE;discoverable= FALSE;pairable= adapter->pairable;break;case(SCAN_PAGE | SCAN_INQUIRY)://设一下模式，在有reply要求的情况下，该步骤还是很重要的
 
adapter->mode= MODE_DISCOVERABLE;discoverable= TRUE;pairable= adapter->pairable;//还要设一个discoverable的时间if(adapter->discov_timeout != 0)adapter_set_discov_timeout(adapter,adapter->discov_timeout);break;caseSCAN_INQUIRY:/*Address the scenario where a low-level application like* hciconfig changed the scan mode */if(adapter->discov_timeout != 0)adapter_set_discov_timeout(adapter,adapter->discov_timeout);/*ignore, this event should not be sent */default:/*ignore, reserved */return;}/*If page scanning gets toggled emit the Pairable property *///这里会发一个property_changed的pairable的signalif((adapter->scan_mode & SCAN_PAGE) != (scan_mode & SCAN_PAGE))emit_property_changed(connection,adapter->path,ADAPTER_INTERFACE,"Pairable",DBUS_TYPE_BOOLEAN,&pairable);if(!discoverable)adapter_set_limited_discoverable(adapter,FALSE);//这里会发一个property_changed的discoverable的signal
 
emit_property_changed(connection,path,ADAPTER_INTERFACE,"Discoverable",DBUS_TYPE_BOOLEAN,&discoverable);adapter->scan_mode= scan_mode;set_mode_complete(adapter);}5.6 WRTIE_SCAN_ENABLE最终引起的状态机的变化在此之前，状态机处于switching的状态，收到了SCAN_MODE_CHANGED的msg。private class Switching extends State {@Overridepublic void enter() {if (DBG) log("Enter Switching:" + getCurrentMessage().what);}@Overridepublic boolean processMessage(Messagemessage) {log("Switching processmessage: " + message.what);boolean retValue = HANDLED;switch(message.what) {case SCAN_MODE_CHANGED:// This event matchesmBluetoothService.switchConnectable action//mPublicState在hotoff到swtiching状态变化时已经被设为STATE_TURNING_ON了，所以这里if没有问题if (mPublicState ==BluetoothAdapter.STATE_TURNING_ON) {// set pairable if it'snot//设置为pairable假如还没有设置的话，这个会先在bluez中检查一下当前是否pairable，我们在前面已经设置好了，所以，这里只是一个检查而已，没有什么实际性的工作
 mBluetoothService.setPairable();//初始化bond state和profile state，这个会在adapter pairable之后，bluetooth turn on之前发生
 mBluetoothService.initBluetoothAfterTurningOn();//这边正式进入到bluetoothon的状态，终于进了这里，哎。。。
 transitionTo(mBluetoothOn);//发送STATE_ON的broadcast
 broadcastState(BluetoothAdapter.STATE_ON);// run bluetooth nowthat it's turned on// Note runBluetoothshould be called only in adapter STATE_ON//连接那些可以自动连接的设备，通知battery，蓝牙打开了
 mBluetoothService.runBluetooth();}break;……