蓝牙（一）蓝牙设置详解

一.蓝牙相关的类

1）BluetoothSettings.java

该类是蓝牙配置和连接管理界面，就是咱们常见的蓝牙界面。它管理着蓝牙界面的加载，蓝牙搜索，蓝牙连接，蓝牙重命名等管理功能。(顺便借用一下大牛做的图片：https://www.cnblogs.com/dixonyy/p/4246057.html)

2）BluetoothEnable.java

该类是蓝牙辅助类，用来管理蓝牙的开和关以及蓝牙状态的标题显示。如打开或关闭蓝牙的switchbar的状态和文本显示。

3）DeviceListPreferenceFragment.java

该类是BluetoothSettings类的父类，是一个抽象类，该类包含了用于保存蓝牙设备的链表以及蓝牙。还包含蓝牙设备的一些回调方法。例如，蓝牙设备的删除、扫描状态的改变、蓝牙状态的改变等回调方法的实现。（回调接口所在的类：BluetoothCallback.java）

final WeakHashMap<CachedBluetoothDevice, BluetoothDevicePreference> mDevicePreferenceMap =

new WeakHashMap<CachedBluetoothDevice, BluetoothDevicePreference>();

该变量保存的是用于显示的蓝牙设备集合，可以删除或添加相应的蓝牙设备。

4)CachedBluetoothDevice.java

缓存蓝牙设备，该类代表了一个远程设备，它包含了蓝牙设备的一些属性（例如蓝牙地址，名字，信号强度等）。该类还可以进行蓝牙设备的连接、配对、断开连接等功能。

5）BluetoothDevice.java

该类也代表了一个远程设备，但是与上面不同的是就相当与你买了一个水杯，水杯就是BluetothDevice,用包装盒包裹起来的就是CachedBluetoothDevice。（个人比喻，有什么不对的可以指点改正，谢谢！）

6）BluetoothDevicePreference.java

该类是在设置界面显示蓝牙设备的偏好类型。点击界面上的配对、连接、断开就是在这操作的。

7）BluetoothAdapter.java

蓝牙适配器，是蓝牙的总中枢，是蓝牙的起点。要想使用蓝牙必须要开启或关闭，它就是蓝牙的总开关。该类让你执行基本的蓝牙任务，例如：初始化发现设别，查询绑定/配对的设备，使用蓝牙MAC地址实例化一个BLuetoothDevice，创建一个BLuetoothServerSocket来监听来自其它蓝牙设备的请求连接，开始扫描蓝牙低功耗设备等等。

8)蓝牙事件管理BluetoothEventManager.java

首先这里注册一个事件接收广播mContext.registerReceiver(mBroadcastReceiver, mAdapterIntentFilter);，用于接收底层驱动发来的广播。然后根据不同的action分发给不同的handler处理。这里的handler都需要通过addHandler函数保存到mHandlerMap中。然后在Handler中调用回调BluetoothCallback（接口），来交给ui上层处理。当然这里继承了BluetoothCallback接口的回调都是事先注册了的registerCallback。在设置中是DeviceListPreferenceFragment注册了。

9）LocalBluetoothAdapter.java

蓝牙接口适配为本地的蓝牙接口适配器，为应用提供接口，同时调用BluetoothAdapter的接口，起到应用和底层的适配作用。

10)CachedBluetoothDeviceManager.java

该类负责管理蓝牙的缓存（已配对的设备和搜索到的设备）主要都保存在List<CachedBluetoothDevice> mCachedDevices中

11)LocalBluetoothProfileManager.java

该类提供访问有效的蓝牙协议对象LocalBluetoothProfile

二.蓝牙流程

1.开启关闭蓝牙

1）开启过程

开启和关闭蓝牙的switchbar的监听状态存在与BluetoothEnable类中，当打开switchbar时

@Overridepublic void onSwitchChanged(Switch switchView, boolean isChecked) {// Show toast message if Bluetooth is not allowed in airplane modeif (isChecked &&!WirelessUtils.isRadioAllowed(mContext, Settings.Global.RADIO_BLUETOOTH)) {Toast.makeText(mContext, R.string.wifi_in_airplane_mode, Toast.LENGTH_SHORT).show();// Reset switch to offswitchView.setChecked(false);}MetricsLogger.action(mContext, MetricsLogger.ACTION_BLUETOOTH_TOGGLE, isChecked);if (mLocalAdapter != null) {

            //若isChecked为true,说明要开启蓝牙mLocalAdapter.setBluetoothEnabled(isChecked);}mSwitch.setEnabled(false);}

public void setBluetoothEnabled(boolean enabled) {boolean success = enabled? mAdapter.enable(): mAdapter.disable();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 for enabled: " + enabled);}syncBluetoothState();}}

--》BluetoothAdapter.enable()-->BluetoothManagerService.enable()

到了BluetoothManagerService就有点麻烦了

BluetoothManagerService.enable()

 public boolean enable() {if ((Binder.getCallingUid() != Process.SYSTEM_UID) &&(!checkIfCallerIsForegroundUser())) {Log.w(TAG,"enable(): not allowed for non-active and non system user");return false;}mContext.enforceCallingOrSelfPermission(BLUETOOTH_ADMIN_PERM,"Need BLUETOOTH ADMIN permission");if (DBG) {Log.d(TAG,"enable():  mBluetooth =" + mBluetooth +" mBinding = " + mBinding);}synchronized(mReceiver) {mQuietEnableExternal = false;mEnableExternal = true;// waive WRITE_SECURE_SETTINGS permission checksendEnableMsg(false);}if (DBG) Log.d(TAG, "enable returning");return true;}

BluetoothManagerService.sendEnableMsg()发送一个handler开启蓝牙的消息

private void sendEnableMsg(boolean quietMode) {mHandler.sendMessage(mHandler.obtainMessage(MESSAGE_ENABLE,quietMode ? 1 : 0, 0));}

BluetoothManagerService.handler

case MESSAGE_ENABLE:if (DBG) {Log.d(TAG, "MESSAGE_ENABLE: mBluetooth = " + mBluetooth);}mHandler.removeMessages(MESSAGE_RESTART_BLUETOOTH_SERVICE);mEnable = true;handleEnable(msg.arg1 == 1);break;

BMS.handleEnable() 只取了部分开启蓝牙的代码

//Enable bluetoothtry {if (!mQuietEnable) {

                        //开启蓝牙if(!mBluetooth.enable()) {Log.e(TAG,"IBluetooth.enable() returned false");}}else {if(!mBluetooth.enableNoAutoConnect()) {Log.e(TAG,"IBluetooth.enableNoAutoConnect() returned false");}}} catch (RemoteException e) {Log.e(TAG,"Unable to call enable()",e);}

接下来又调用了IBluetooth.enable(),具体实现是在AdapterService中，进而调用了AdapterService.enable()-->enable(boolean),代码如下：

public synchronized boolean enable(boolean quietMode) {enforceCallingOrSelfPermission(BLUETOOTH_ADMIN_PERM, "Need BLUETOOTH ADMIN permission");debugLog("enable() - Enable called with quiet mode status =  " + mQuietmode);mQuietmode = quietMode;Message m = mAdapterStateMachine.obtainMessage(AdapterState.BLE_TURN_ON);mAdapterStateMachine.sendMessage(m);return true;}

接下来就到状态机AdapterState了，下面对BLE_TURN_ON消息进行处理

 case BLE_TURN_ON: notifyAdapterStateChange(BluetoothAdapter.STATE_BLE_TURNING_ON);mPendingCommandState.setBleTurningOn(true);transitionTo(mPendingCommandState);sendMessageDelayed(BLE_START_TIMEOUT, BLE_START_TIMEOUT_DELAY);adapterService.BleOnProcessStart();break;

蓝牙开启之后，状态肯定变化了，所以也要发送一个广播，通知调用蓝牙的地方告诉它蓝牙状态已经改变，快做其它处理吧

private void notifyAdapterStateChange(int newState) {AdapterService adapterService = mAdapterService;AdapterProperties adapterProperties = mAdapterProperties;if ((adapterService == null) || (adapterProperties == null)) {errorLog("notifyAdapterStateChange after cleanup:" + newState);return;}int oldState = adapterProperties.getState();adapterProperties.setState(newState);infoLog("Bluetooth adapter state changed: " + oldState + "-> " + newState); adapterService.updateAdapterState(oldState, newState);}

下面就到了adapterservice里进行状态的更新了

void updateAdapterState(int prevState, int newState){if (mCallbacks !=null) {int n=mCallbacks.beginBroadcast();debugLog("updateAdapterState() - Broadcasting state to " + n + " receivers.");for (int i=0; i <n;i++) {try { mCallbacks.getBroadcastItem(i).onBluetoothStateChange(prevState,newState);}  catch (RemoteException e) {debugLog("updateAdapterState() - Callback #" + i + " failed ("  + e + ")");}}mCallbacks.finishBroadcast();}}

上面的加红的到底跳到哪个地方了哪？答案就是又回到BluetoothManagerService里了，这个回调主要实现的功能就是发送一个蓝牙状态改变的广播。

private final IBluetoothCallback mBluetoothCallback =  new IBluetoothCallback.Stub() {@Overridepublic void onBluetoothStateChange(int prevState, int newState) throws RemoteException  {Message msg = mHandler.obtainMessage(MESSAGE_BLUETOOTH_STATE_CHANGE,prevState,newState);mHandler.sendMessage(msg);}};

懒得做时序图了，顺便再借用以下别人的。