android4.0蓝牙使能的详细解析

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。

posted @ 2014-07-02 09:26 xiaochao1234 阅读(1131) 评论(0) 编辑收藏举报

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android4.0蓝牙使能的详细解析

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