Android 蓝牙 OPP传输文件（上）

转载自：http://blog.csdn.net/vnanyesheshou/article/details/70256004

Android蓝牙功能（传统蓝牙、ble、hid）这三方面功能之前的博客都已经写了。现在接着了解蓝牙OPP传输文件相关功能。Android手机使用中，经常会用到通过蓝牙分享文件给附近的朋友。那么具体是如何实现的，大部分朋友都不是很清楚。看一下源码是如何实现该功能的。

---

1 BluetoothOppLauncherActivity

Android手机点击某文件进行蓝牙分享的时候，会跳转到系统自带应用Bluetooth中。
具体文件：packages/apps/Bluetooth/src/com/android/bluetooth/opp/BluetoothOppLauncherActivity.java
看一下BluetoothOppLauncherActivity是如何处理分享文件请求的。

if (action.equals(Intent.ACTION_SEND) || action.equals(Intent.ACTION_SEND_MULTIPLE)) {
            //Check if Bluetooth is available in the beginning instead of at the end
            if (!isBluetoothAllowed()) {
                Intent in = new Intent(this, BluetoothOppBtErrorActivity.class);
                in.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                in.putExtra("title", this.getString(R.string.airplane_error_title));
                in.putExtra("content", this.getString(R.string.airplane_error_msg));
                startActivity(in);
                finish();
                return;
            }
            //..........下面接着说。
}
 
 
  
  

BluetoothOppLauncherActivity并没有界面(没有setContentView)，只是一个中转站,它根据当前蓝牙等相关状态进行跳转。Intent.ACTION_SEND和Intent.ACTION_SEND_MULTIPLE的区别是前者表示单个文件，后者表示多个文件。这里只研究下分享单个文件，分享单个文件懂了，多个文件道理类似。
其中isBluetoothAllowed()函数会先判断飞行模式是否开启，如果没有开启则返回true。如果开启，则进行下一步判断飞行模式是否重要，如果不重要则返回true（说明蓝牙可以使用）。如果重要则继续分析飞行模式下是否可以打开蓝牙，可以打开蓝牙则返回true，否则返回false。总的来说该函数就是判断当前蓝牙是否允许使用。不允许使用蓝牙则跳转到BluetoothOppBtErrorActivity。
接着向下：

if (action.equals(Intent.ACTION_SEND)) { //单个文件
    final String type = intent.getType();
    final Uri stream = (Uri)intent.getParcelableExtra(Intent.EXTRA_STREAM);
    CharSequence extra_text = intent.getCharSequenceExtra(Intent.EXTRA_TEXT);
    if (stream != null && type != null) { //分享文件
        Thread t = new Thread(new Runnable() {
            public void run() {
                BluetoothOppManager.getInstance(BluetoothOppLauncherActivity.this)
                    .saveSendingFileInfo(type,stream.toString(), false);
                launchDevicePicker();
                finish();
            }
        });
        t.start();
        return;
    } else if (extra_text != null && type != null) { //分享text字符串，没有文件
        final Uri fileUri = creatFileForSharedContent(this, extra_text); //创建文件,将内容写入文件
        if (fileUri != null) {
            Thread t = new Thread(new Runnable() {
                public void run() {
                    BluetoothOppManager.getInstance(BluetoothOppLauncherActivity.this)
                        .saveSendingFileInfo(type,fileUri.toString(), false);
                    launchDevicePicker();
                    finish();
                }
            });
            t.start();
            return;
        }
        //.........
}
 
 
  
  

使用过Android系统分享的应该知道，其支持文件(图片、视频等)、字符串。而这里会对文件、字符串进行区分处理，字符串则先创建文件然后在进行分享。
launchDevicePicker()函数中先判断蓝牙是否开启。
如果蓝牙没有开启则跳转到BluetoothOppBtEnableActivity显示dialog（询问是否开启蓝牙），点击取消则则退出，点击打开则打开蓝牙并跳到BluetoothOppBtEnablingActivity（该activity主要显示一个progress dialog）。当蓝牙打开，则BluetoothOppBtEnablingActivity 界面finish。BluetoothOppReceiver广播接收者接收到蓝牙开启，跳转到DevicePickerActivity界面（系统Settings应用）。
如果蓝牙已开启，则直接跳转到跳转到DevicePickerActivity界面（系统Settings应用）。
launchDevicePicker()下的跳转代码：

//ACTION_LAUNCH="android.bluetooth.devicepicker.action.LAUNCH"
Intent in1 = new Intent(BluetoothDevicePicker.ACTION_LAUNCH);
in1.setFlags(Intent.FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS);
in1.putExtra(BluetoothDevicePicker.EXTRA_NEED_AUTH, false);
in1.putExtra(BluetoothDevicePicker.EXTRA_FILTER_TYPE,
        BluetoothDevicePicker.FILTER_TYPE_TRANSFER);
in1.putExtra(BluetoothDevicePicker.EXTRA_LAUNCH_PACKAGE,
        Constants.THIS_PACKAGE_NAME);
in1.putExtra(BluetoothDevicePicker.EXTRA_LAUNCH_CLASS,
        BluetoothOppReceiver.class.getName());
startActivity(in1);
 
 
  
  

系统Settings应用中AndroidManifest.xml中发现对应action的DevicePickerActivity，所以该跳转会跳转到系统Settings应用中的DevicePickerActivity中。

<activity android:name=".bluetooth.DevicePickerActivity"
        android:uiOptions="splitActionBarWhenNarrow"
        android:theme="@android:style/Theme.Holo.DialogWhenLarge"
        android:label="@string/device_picker"
        android:clearTaskOnLaunch="true">
    <intent-filter>
        <action android:name="android.bluetooth.devicepicker.action.LAUNCH" />
        <category android:name="android.intent.category.DEFAULT" />
    </intent-filter>
</activity>
 
 
  
  

---

2 DevicePicker

DevicePickerActivity中代码很简单，只是设置了布局。
setContentView(R.layout.bluetooth_device_picker);
bluetooth_device_picker.xml中有一个fragment指向DevicePickerFragment，也就是主要的处理在DevicePickerFragment中。
DevicePickerFragment界面会显示出配对、扫描到的蓝牙列表。可以点击一个设备进行分享文件。

void onDevicePreferenceClick(BluetoothDevicePreference btPreference) {
    mLocalAdapter.stopScanning(); //停止扫描
    LocalBluetoothPreferences.persistSelectedDeviceInPicker(
            getActivity(), mSelectedDevice.getAddress());
    if ((btPreference.getCachedDevice().getBondState() ==
            BluetoothDevice.BOND_BONDED) || !mNeedAuth) {
        sendDevicePickedIntent(mSelectedDevice);
        finish();
    } else {
        super.onDevicePreferenceClick(btPreference);
    }
}
 
 
  
  

点击设备，会判断是否是绑定状态，或者mNeedAuth为false。mNeedAuth是通过intent传过来的值为false。所以满足条件。
接着看sendDevicePickedIntent()。该函数就是发了一个广播。

private void sendDevicePickedIntent(BluetoothDevice device) {
    //"android.bluetooth.devicepicker.action.DEVICE_SELECTED"
    Intent intent = new Intent(BluetoothDevicePicker.ACTION_DEVICE_SELECTED);
    intent.putExtra(BluetoothDevice.EXTRA_DEVICE, device);
    if (mLaunchPackage != null && mLaunchClass != null) {
        intent.setClassName(mLaunchPackage, mLaunchClass);
    }
    getActivity().sendBroadcast(intent);
}
 
 
  
  

---

3 BluetoothOppReceiver

查看系统应用Bluetooth中的BluetoothOppReceiver类中对此广播进行了处理。但是Bluetooth中的AndroidManifest.xml中该广播接收者的注册并没有添加此action。但是却可以接收此广播。原因应该是该广播发送时携带了包名、类名。

<receiver
    android:process="@string/process"
    android:exported="true"
    android:name=".opp.BluetoothOppReceiver"
    android:enabled="@bool/profile_supported_opp">
    <intent-filter>
        <action android:name="android.bluetooth.adapter.action.STATE_CHANGED" />
        <!--action android:name="android.intent.action.BOOT_COMPLETED" /-->
        <action android:name="android.btopp.intent.action.OPEN_RECEIVED_FILES" />
    </intent-filter>
</receiver>  
 
 
  
  

BluetoothOppReceiver收到此广播后的主要处理代码如下，将此条记录添加到数据库。

// Insert transfer session record to database
mOppManager.startTransfer(remoteDevice);
 
 
  
  

BluetoothOppManager对象调用startTransfer方法。在startTransfer方法中创建一个InsertShareInfoThread线程并开始运行。
InsertShareInfoThread线程中区分分享的是一个文件还是多个文件。我们这里只看下处理单个文件insertSingleShare()函数。

if (mIsMultiple) {//多个文件
    insertMultipleShare();
} else { //单个文件
    insertSingleShare();
}

private void insertSingleShare() {
    ContentValues values = new ContentValues();
    values.put(BluetoothShare.URI, mUri);
    values.put(BluetoothShare.MIMETYPE, mTypeOfSingleFile);
    values.put(BluetoothShare.DESTINATION, mRemoteDevice.getAddress());
    if (mIsHandoverInitiated) {
        values.put(BluetoothShare.USER_CONFIRMATION,
                BluetoothShare.USER_CONFIRMATION_HANDOVER_CONFIRMED);
    }
    final Uri contentUri = mContext.getContentResolver().insert(BluetoothShare.CONTENT_URI,
            values);
} 
 
 
  
  

由mContext.getContentResolver().insert()可知其有对应的provider。BluetoothOppProvider继承了ContextProvider。查看BluetoothOppProvider中的insert方法。

public Uri insert(Uri uri, ContentValues values) {
.....
if (rowID != -1) {
    context.startService(new Intent(context, BluetoothOppService.class));
    ret = Uri.parse(BluetoothShare.CONTENT_URI + "/" + rowID);
    context.getContentResolver().notifyChange(uri, null);
}
 
 
  
  

由上可知通过蓝牙分享的时候会start BluetoothOppService。

---

4 BluetoothOppService

在BluetoothOppService中会监听数据库字段（BluetoothShare.CONTENT_URI）的变化，调用updateFromProvider()函数进行处理。onCreate()和onStartCommand()函数都会调用updateFromProvider()。
updateFromProvider() ->创建线程UpdateThread -> insertShare()。

private void insertShare(Cursor cursor, int arrayPos) {
     if (info.isReadyToStart()) {
         if (info.mDirection == BluetoothShare.DIRECTION_OUTBOUND) { //向外分享、发送
             /* 检查文件是否存在 */
         }
     }
     if (mBatchs.size() == 0) {
         if (info.mDirection == BluetoothShare.DIRECTION_OUTBOUND)  {
   
   //向外分享、发送
             mTransfer = new BluetoothOppTransfer(this, mPowerManager, newBatch);
         } else if (info.mDirection == BluetoothShare.DIRECTION_INBOUND) { //接收
             mServerTransfer = new BluetoothOppTransfer(this, mPowerManager, newBatch,
                     mServerSession);
         }

         if (info.mDirection == BluetoothShare.DIRECTION_OUTBOUND && mTransfer != null) {
             mTransfer.start();
         } else if (info.mDirection == BluetoothShare.DIRECTION_INBOUND
                 && mServerTransfer != null) {
             mServerTransfer.start();
         }
     }
     //........
}
 
 
  
  

---

5 BluetoothOppTransfer

这里只说向外发送、分享。接着看BluetoothOppTransfer。

public void start() {
    //检查蓝牙是否打开，保证安全
    if (!mAdapter.isEnabled()) {
        return;
    }
    if (mHandlerThread == null) {
        //......
        if (mBatch.mDirection == BluetoothShare.DIRECTION_OUTBOUND) {
            /* for outbound transfer, we do connect first */
            startConnectSession();
        } 
        //....
    }
}
 
 
  
  

startConnectSession()函数中开始向远端设备进行连接，该函数中主要就是创建SocketConnectThread线程，用来连接其他设备。
SocketConnectThread线程主要代码：

try {
    
    
    if (mIsInterrupted) {
    
    
        Log.e(TAG, "btSocket connect interrupted ");
        markConnectionFailed(mBtSocket);
        return;
    } else {
    
    
        mBtSocket = mDevice.createInsecureL2capSocket(mL2cChannel);
    }
} catch (IOException e1) {
    
    
    Log.e(TAG, "L2cap socket create error", e1);
    connectRfcommSocket();
    return;
}
try {
    
    
	mBtSocket.connect();
	if (D) {
    
    
	    Log.v(TAG, "L2cap socket connection attempt took " + (System.currentTimeMillis()
	            - mTimestamp) + " ms");
	}
	BluetoothObexTransport transport;
	transport = new BluetoothObexTransport(mBtSocket);
	BluetoothOppPreference.getInstance(mContext).setName(mDevice, mDevice.getName());
	if (V) {
    
    
	    Log.v(TAG, "Send transport message " + transport.toString());
	}
	mSessionHandler.obtainMessage(TRANSPORT_CONNECTED, transport).sendToTarget();
}
} catch (IOException e) {
    
    
	\...
}

这里先创建BluetoothSocket，然后通过BluetoothSocket进行连接。
Socket应该是L2capSocket。
transport = new BluetoothObexTransport(mBtSocket);后面会用到。

case TRANSPORT_CONNECTED:
    /*
    * RFCOMM connected is for outbound share only! Create
    * BluetoothOppObexClientSession and start it
    */
    if (V) {
    
    
        Log.v(TAG, "Transfer receive TRANSPORT_CONNECTED msg");
    }

    mTransport = (ObexTransport) msg.obj;
    startObexSession();

    break;

连接成功后，通过Handler调用startObexSession()->new BluetoothOppObexClientSession ->BluetoothOppObexClientSession .start()

---

6 BluetoothOppObexClientSession

BluetoothOppObexClientSession类说明该设备作为obex client，向server发送文件。该类中主要功能：obex连接、发送分享文件的信息，发送数据等。
start() -> 创建ClientThread线程并运行 -> connect()。
在connect()函数中，通过mTransport1（BluetoothOppRfcommTransport类型，该类型中主要包含之前创建的BluetoothSocket）对象，创建client session，连接远端设备。

private void connect(int numShares) {
    try {
   
   //创建obex client
        mCs = new ClientSession(mTransport1);
        mConnected = true;
    } catch (IOException e1) {
    }
    if (mConnected) {
        mConnected = false;
        HeaderSet hs = new HeaderSet(); //obex 连接携带信息
        hs.setHeader(HeaderSet.COUNT, (long) numShares);//文件数量
        synchronized (this) {
            mWaitingForRemote = true;
        }
        try { //obex连接
            mCs.connect(hs);
            mConnected = true;
        } catch (IOException e) {
        }
    }
    //.....
}
 
 
  
  

obex连接成功后，调用doSend(),该函数中先检查下文件是否存在，然后查看连接状态，连接状态下并且存在文件则sendFile才真正的开始发送文件。之会将相应的状态发送到BluetoothOppTransfer中。

private void doSend() {
    int status = BluetoothShare.STATUS_SUCCESS;
    while (mFileInfo == null) { //检查文件是否存在
        try {
            Thread.sleep(50);
        } catch (InterruptedException e) {
            status = BluetoothShare.STATUS_CANCELED;
        }
    }
    //检查连接状态
    if (!mConnected) {
        status = BluetoothShare.STATUS_CONNECTION_ERROR;
    }
    if (status == BluetoothShare.STATUS_SUCCESS) {
        /* 发送文件*/
        if (mFileInfo.mFileName != null) {
            status = sendFile(mFileInfo);
        } else {
            status = mFileInfo.mStatus;
        }
        waitingForShare = true;
    } else {
        Constants.updateShareStatus(mContext1, mInfo.mId, status);
    }
    //发送此次操作是否成功等信息。
}
 
 
  
  

真正的发送文件是在sendFile()函数中。不过该函数太长就不全贴出来了，只说一下重要的地方。

1 发送文件信息

HeaderSet request = new HeaderSet();
request.setHeader(HeaderSet.NAME, fileInfo.mFileName);  //文件名
request.setHeader(HeaderSet.TYPE, fileInfo.mMimetype);   //文件类型
request.setHeader(HeaderSet.LENGTH, fileInfo.mLength);  //文件大小
//通过obex发送传递文件请求
putOperation = (ClientOperation)mCs.put(request);
//putOperation类型为ClientOperation，具体java.obex包下的类没有向外透漏，不太清楚是具体怎么回事。
 
 
  
  

2 获取obex层输入输出流

 //获取输入输出流。
outputStream = putOperation.openOutputStream();
inputStream = putOperation.openInputStream();
 
 
  
  

3 发送第一个包

//从文件中读取内容
BufferedInputStream a = new BufferedInputStream(fileInfo.mInputStream, 0x4000);
readLength = readFully(a, buffer, outputBufferSize);
//先向远程设备发送第一个包 该操作会阻塞等待远端设备的接收读取。
outputStream.write(buffer, 0, readLength);
position += readLength;
如果文件太小，一个包就已经发送完，则将输出流关闭。outputStream.close();
 
 
  
  

4 查看回应
接着查看远端设备的回应，是否接受。

/* check remote accept or reject */
responseCode = putOperation.getResponseCode();
if (responseCode == ResponseCodes.OBEX_HTTP_CONTINUE
     || responseCode == ResponseCodes.OBEX_HTTP_OK) {
     //接收
     okToProceed = true;
     updateValues = new ContentValues();
     updateValues.put(BluetoothShare.CURRENT_BYTES, position);
     mContext1.getContentResolver().update(contentUri, updateValues, null,
                                    null);
} else {
   
   //拒绝接收
      Log.i(TAG, "Remote reject, Response code is " + responseCode);
}
 
 
  
  

5 判断发送数据
接着循环判断、从文件读取数据、发送数据。

while (!mInterrupted && okToProceed && (position != fileInfo.mLength)) {
    readLength = a.read(buffer, 0, outputBufferSize);
    outputStream.write(buffer, 0, readLength);

    /* check remote abort */
    responseCode = putOperation.getResponseCode();
    if (responseCode != ResponseCodes.OBEX_HTTP_CONTINUE
            && responseCode != ResponseCodes.OBEX_HTTP_OK) {
        okToProceed = false;
    } else {
        position += readLength;
        //更行进度
        updateValues = new ContentValues();
        updateValues.put(BluetoothShare.CURRENT_BYTES, position);
        mContext1.getContentResolver().update(contentUri, updateValues,
                null, null);
    }
}
 
 
  
  

outputStream是PrivateOutputStream对象

PrivateOutputStream.java
public synchronized void write(byte[] buffer, int offset, int count) throws IOException {
    
    
    int offset1 = offset;
    int remainLength = count;

    if (buffer == null) {
    
    
        throw new IOException("buffer is null");
    }
    if ((offset | count) < 0 || count > buffer.length - offset) {
    
    
        throw new IndexOutOfBoundsException("index outof bound");
    }

    ensureOpen();
    mParent.ensureNotDone();
    while ((mArray.size() + remainLength) >= mMaxPacketSize) {
    
    
        int bufferLeft = mMaxPacketSize - mArray.size();
        mArray.write(buffer, offset1, bufferLeft);
        offset1 += bufferLeft;
        remainLength -= bufferLeft;
        mParent.continueOperation(true, false);
    }
    if (remainLength > 0) {
    
    
        mArray.write(buffer, offset1, remainLength);
    }
}

public synchronized boolean continueOperation(boolean sendEmpty, boolean inStream)
         throws IOException {
    
    

     // One path to the first put operation - the other one does not need to
     // handle SRM, as all will fit into one packet.

     if (mGetOperation) {
    
    
         ...
     } else {
    
    
         // PUT operation
         if ((!inStream) && (!mOperationDone)) {
    
    
             // to deal with outputstream in put operation
             if (mReplyHeader.responseCode == -1) {
    
    
                 mReplyHeader.responseCode = ResponseCodes.OBEX_HTTP_CONTINUE;
             }
             sendRequest(ObexHelper.OBEX_OPCODE_PUT);
             return true;
         } else if ((inStream) && (!mOperationDone)) {
    
    
             // How to deal with inputstream  in put operation ?
             return false;

         } else if (mOperationDone) {
    
    
             return false;
         }

     }
     return false;
 }

mGetOperation为ClientOperation构造函数中的type。

public ClientOperation(int maxSize, ClientSession p, HeaderSet header, boolean type)
        throws IOException {
    
    

    mParent = p;
    mEndOfBodySent = false;
    mInputOpen = true;
    mOperationDone = false;
    mMaxPacketSize = maxSize;
    mGetOperation = type;
    ...
}

前面有putOperation = (ClientOperation)mCs.put(request); type赋值为false。

ClientSession.java
public Operation put(HeaderSet header) throws IOException {
    
    
    ...
    return new ClientOperation(mMaxTxPacketSize, this, head, false);
}

因此后面调用sendRequest(ObexHelper.OBEX_OPCODE_PUT);

后面和connect流程相同。