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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......

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。