[NFC]NFC启动流程2

正式进入NFCService.java，开始NFC framework探索， jiu～～～～

接上篇文章内容，进入NfcService后，就开始启动各种Services，Hold on，一大波代码马上到来：

{mUserId = ActivityManager.getCurrentUser();mContext = nfcApplication;//@paul: Tag相关; extend INfcTag;最终调用到NativeNfcTagmNfcTagService = new TagService();//@paul: 上层APP 调用 NFC 功能时, 中间变量adapter;extend INfcAdaptor;最终调用到NfcAdaptormNfcAdapter = new NfcAdapterService();Log.i(TAG, "Starting NFC service");sService = this;//@paul: NFC与屏幕解锁的关系,含OFF / ON_LOCK / ON_UNLOCKmScreenStateHelper = new ScreenStateHelper(mContext);mContentResolver = mContext.getContentResolver();//@paul: 底层Driver 相关的JNI 接口mDeviceHost = new NativeNfcManager(mContext, this);//@paul: 还不懂mNfcUnlockManager = NfcUnlockManager.getInstance();//@paul: 和handover 相关接口;主要是bluetooth, 实际上wifi 也是可以实现的mHandoverManager = new HandoverManager(mContext);boolean isNfcProvisioningEnabled = false;try {isNfcProvisioningEnabled = mContext.getResources().getBoolean(R.bool.enable_nfc_provisioning);} catch (NotFoundException e) {}//@paul: 设备是否在setup wizard阶段支持接收NFC 数据if (isNfcProvisioningEnabled) {mInProvisionMode = Settings.Secure.getInt(mContentResolver,Settings.Global.DEVICE_PROVISIONED, 0) == 0;} else {mInProvisionMode = false;}//@paul: 收到NFC 消息处理流程, 最终调用到dispatchTag()mNfcDispatcher = new NfcDispatcher(mContext, mHandoverManager, mInProvisionMode);//@paul: 基于LLCP 连接的服务,含NdefPushService/SnepService/P2pEventManager//@paul: 此类会定义doPut/doGet, 后续还会提到mP2pLinkManager = new P2pLinkManager(mContext, mHandoverManager,mDeviceHost.getDefaultLlcpMiu(), mDeviceHost.getDefaultLlcpRwSize());//@paul: 获取shared_pref 信息，一般存储位置在/data/data/<包名>/shared_prefsmPrefs = mContext.getSharedPreferences(PREF, Context.MODE_PRIVATE);mPrefsEditor = mPrefs.edit();//@paul: 和security相关，主要是读取解析/etc/nfcee_access.xml文件mNfceeAccessControl = new NfceeAccessControl(mContext);mState = NfcAdapter.STATE_OFF;//@paul: 依prefs 文件定义，检查NdefPush 是否enablemIsNdefPushEnabled = mPrefs.getBoolean(PREF_NDEF_PUSH_ON, NDEF_PUSH_ON_DEFAULT);setBeamShareActivityState(mIsNdefPushEnabled);mIsDebugBuild = "userdebug".equals(Build.TYPE) || "eng".equals(Build.TYPE);//@paul: 电源管理模块，主要是屏幕状态与NFC 是否响应有关系mPowerManager = (PowerManager) mContext.getSystemService(Context.POWER_SERVICE);//@paul: 获取WakeLock//步骤:1.获取powermanager 实例//2.生成实例: new WakeLock//3.通过acquire() 获取锁mRoutingWakeLock = mPowerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "NfcService:mRoutingWakeLock");//@paul: 屏幕锁mKeyguard = (KeyguardManager) mContext.getSystemService(Context.KEYGUARD_SERVICE);mUserManager = (UserManager) mContext.getSystemService(Context.USER_SERVICE);mScreenState = mScreenStateHelper.checkScreenState();//@Paul: 将NFC 加入到系统service中ServiceManager.addService(SERVICE_NAME, mNfcAdapter);// Intents for all users//@paul: 注册屏幕亮/灭，用户激活和切换IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_OFF);filter.addAction(Intent.ACTION_SCREEN_ON);filter.addAction(Intent.ACTION_USER_PRESENT);filter.addAction(Intent.ACTION_USER_SWITCHED);registerForAirplaneMode(filter);mContext.registerReceiverAsUser(mReceiver, UserHandle.ALL, filter, null, null);IntentFilter ownerFilter = new IntentFilter(Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);ownerFilter.addAction(Intent.ACTION_EXTERNAL_APPLICATIONS_UNAVAILABLE);mContext.registerReceiver(mOwnerReceiver, ownerFilter);//@paul: 关注程序安装和卸载ownerFilter = new IntentFilter();ownerFilter.addAction(Intent.ACTION_PACKAGE_ADDED);ownerFilter.addAction(Intent.ACTION_PACKAGE_REMOVED);ownerFilter.addDataScheme("package");mContext.registerReceiver(mOwnerReceiver, ownerFilter);updatePackageCache();PackageManager pm = mContext.getPackageManager();//@paul: 判断系统是否支持卡模拟mIsHceCapable = pm.hasSystemFeature(PackageManager.FEATURE_NFC_HOST_CARD_EMULATION);if (mIsHceCapable) {mCardEmulationManager = new CardEmulationManager(mContext);}mForegroundUtils = ForegroundUtils.getInstance();//@paul: 开始执行NFC , 参数TASK_BOOTnew EnableDisableTask().execute(TASK_BOOT); // do blocking boot tasks}

看完这么多的代码，是不是还不确定各个部分的意义。没有关系，继续挖。

1. TagService

此部分实现的接口都在INfcTag.aidl中定义，接口如下：

{int close(int nativeHandle);int connect(int nativeHandle, int technology);int reconnect(int nativeHandle);int[] getTechList(int nativeHandle);boolean isNdef(int nativeHandle);boolean isPresent(int nativeHandle);TransceiveResult transceive(int nativeHandle, in byte[] data, boolean raw);NdefMessage ndefRead(int nativeHandle);int ndefWrite(int nativeHandle, in NdefMessage msg);int ndefMakeReadOnly(int nativeHandle);boolean ndefIsWritable(int nativeHandle);int formatNdef(int nativeHandle, in byte[] key);Tag rediscover(int nativehandle);int setTimeout(int technology, int timeout);int getTimeout(int technology);void resetTimeouts();boolean canMakeReadOnly(int ndefType);int getMaxTransceiveLength(int technology);boolean getExtendedLengthApdusSupported();}

以其中connect()函数为例，解释一下此部分的流程和逻辑，其余的函数基本上可以参考connect()函数：

@Overridepublic int connect(int nativeHandle, int technology) throws RemoteException {//@paul: 检查manifest中是否有nfc操作权限NfcPermissions.enforceUserPermissions(mContext);TagEndpoint tag = null;//@paul: 判断NFC是否启动，在执行enableInternal()时，条件为真if (!isNfcEnabled()) {return ErrorCodes.ERROR_NOT_INITIALIZED;}/* find the tag in the hmap */tag = (TagEndpoint) findObject(nativeHandle);if (tag == null) {return ErrorCodes.ERROR_DISCONNECT;}//@pau

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