源：http://www.cnblogs.com/xiaochao1234/p/3818193.html
本文详细分析了android4.0 中蓝牙使能的过程，相比较android2.3，4.0中的蓝牙最大的差别在于UI上on/off的伪开关。在android4.0中加入了 adapter的状态机。所谓的状态机就类似于状态转换图，在一个状态收到某个特定的命令会变成另外一个状态，不同的命令可以跳转到不同的状态（当然也有 可能到同一状态）。adapter的初始状态为poweroff，在android系统启动的时候会进入warmup状态，同时会进行UUID的add， 该操作会引起propertychanged的UUID signal，该signal会使得状态从warmup变换到hotoff状态。因此在UI端off时其实adapter已经处于hotoff状态而不是 poweroff状态。这一点是很关键的。在正文中，我会从假如我不知道这些开始来描绘整个使能的过程。
正文：
毫无疑问，bluetooth的打开是在Settings中进行的操作。因此，冤有头，债有主，我们来到了Settings.java中，果然发现了相关的代码如下：
mBluetoothEnabler =new BluetoothEnabler(context, new Switch(context));
于是，我们得以进入真正的蓝牙操作的殿堂，好好进去看看吧。
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getInstance
public 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getInstance
static 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DefaultAdapter
public 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BluetoothEventManager
BluetoothEventManager(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 off
if (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 switches
if (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setScanMode
return 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.java
BluetoothServicebluetooth = 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 bug988521
if(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true
if (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 {
@Override
public void enter() {
if (DBG) log("Enter PowerOff:" + getCurrentMessage().what);
}
@Override
public 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 loop
int 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extra1.5
if(!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 ioctl
for (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_sock
if (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started
if (!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 cache
if (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State
if (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 {
@Override
public void enter() {
if (DBG) log("Enter WarmUp:" + getCurrentMessage().what);
}
@Override
public 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 {
@Override
public void enter() {
if (DBG) log("Enter HotOff:" + getCurrentMessage().what);
}
@Override
public 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 todo
if(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);
#endif
return;
}
//把discoverable的timeout清空
adapter_remove_discov_timeout(adapter);
//这里开始，是设为SCAN_PAGE| SCAN_INQUIRY
switch(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signal
if((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 {
@Override
public void enter() {
if (DBG) log("Enter Switching:" + getCurrentMessage().what);
}
@Override
public 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;
……
至此，蓝牙的使能主要过程已经全部搞定。