因为客户端可能会多次发起连接请求，所以当此处文件传输完成后(不管成功或失败)，都需要重新 startService

，让服务再次堵塞等待客户端的连接请求

FileTransfer 包含三个字段，MD5码值用于校验文件的完整性，fileLength

是为了用于计算文件的传输进度

public class FileTransfer implements Serializable {

//文件路径

private String

filePath;

//文件大小

private long

fileLength;

//MD5码

private String md5;

···

}

为了将文件传输进度发布到外部界面，所以除了需要启动Service外，界面还需要绑定Service，此处就需要用到一个更新文件传输状态的接口

public

interface OnProgressChangListener {

//当传输进度发生变化时

void

onProgressChanged(FileTransfer fileTransfer, int

progress);

//当传输结束时

void

onTransferFinished(File file);

}

因此，需要将 progressChangListener

作为参数传给  WifiServerService

，并在进度变化时更新进度对话框

private

WifiServerService.OnProgressChangListener progressChangListener =

new WifiServerService.OnProgressChangListener() {

@Override

public

void onProgressChanged(final FileTransfer fileTransfer, final int

progress) {

runOnUiThread(new Runnable()

{

@Override

public void run() {

progressDialog.setMessage("文件名： " + new

File(fileTransfer.getFilePath()).getName());

progressDialog.setProgress(progress);

progressDialog.show();

}

});

}

@Override

public

void onTransferFinished(final File file) {

runOnUiThread(new Runnable()

{

@Override

public void run() {

progressDialog.cancel();

if (file

!= null && file.exists()) {

openFile(file.getPath());

}

}

});

}

};

四、客户端加入群组并发起文件传输请求

文件发送界面 SendFileActivity 需要实现

DirectActionListener 接口 首先，需要先注册P2P广播，以便获取周边设备信息以及连接状态

@Override

protected

void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_send_file);

initView();

mWifiP2pManager =

(WifiP2pManager)

getSystemService(Context.WIFI_P2P_SERVICE);

mChannel =

mWifiP2pManager.initialize(this, getMainLooper(), this);

broadcastReceiver = new

DirectBroadcastReceiver(mWifiP2pManager, mChannel,

this);

registerReceiver(broadcastReceiver,

DirectBroadcastReceiver.getIntentFilter());

}

通过

discoverPeers 方法搜索周边设备，回调函数用于通知方法是否调用成功

mWifiP2pManager.discoverPeers(mChannel, new

WifiP2pManager.ActionListener() {

@Override

public

void onSuccess() {

showToast("Success");

}

@Override

public

void onFailure(int reasonCode) {

showToast("Failure");

loadingDialog.cancel();

}

});

当搜索结束后，系统就会触发

WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION 广播，此时就可以调用

requestPeers 方法获取设备列表信息，此处用 RecyclerView 展示列表，在

onPeersAvailable 方法刷新列表

mWifiP2pManager.requestPeers(mChannel, new

WifiP2pManager.PeerListListener() {

@Override

public

void onPeersAvailable(WifiP2pDeviceList peers) {

mDirectActionListener.onPeersAvailable(peers.getDeviceList());

}

});

@Override

public

void onPeersAvailable(Collection wifiP2pDeviceList) {

Log.e(TAG, "onPeersAvailable

:" + wifiP2pDeviceList.size());

this.wifiP2pDeviceList.clear();

this.wifiP2pDeviceList.addAll(wifiP2pDeviceList);

deviceAdapter.notifyDataSetChanged();

loadingDialog.cancel();

}

之后，通过点击事件选中群主(服务器端)设备，通过 connect

方法请求与之进行连接

private void connect() {

WifiP2pConfig config = new WifiP2pConfig();

if

(config.deviceAddress != null && mWifiP2pDevice != null)

{

config.deviceAddress =

mWifiP2pDevice.deviceAddress;

config.wps.setup =

WpsInfo.PBC;

showLoadingDialog("正在连接 " +

mWifiP2pDevice.deviceName);

mWifiP2pManager.connect(mChannel, config, new

WifiP2pManager.ActionListener() {

@Override

public void onSuccess() {

Log.e(TAG,

"connect onSuccess");

}

@Override

public void onFailure(int reason) {

showToast("连接失败 " + reason);

dismissLoadingDialog();

}

});

}

}

此处依然无法通过函数函数来判断连接结果，需要依靠系统发出的

WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION

方法来获取到连接结果，在此处可以通过 requestConnectionInfo

获取到组连接信息，信息最后通过 onConnectionInfoAvailable

方法传递出来，在此可以判断当前设备是否为群主，获取群组IP地址

@Override

public void

onConnectionInfoAvailable(WifiP2pInfo wifiP2pInfo) {

dismissLoadingDialog();

wifiP2pDeviceList.clear();

deviceAdapter.notifyDataSetChanged();

btn_disconnect.setEnabled(true);

btn_chooseFile.setEnabled(true);

Log.e(TAG,

"onConnectionInfoAvailable");

Log.e(TAG,

"onConnectionInfoAvailable groupFormed: " +

wifiP2pInfo.groupFormed);

Log.e(TAG,

"onConnectionInfoAvailable isGroupOwner: " +

wifiP2pInfo.isGroupOwner);

Log.e(TAG,

"onConnectionInfoAvailable getHostAddress: " +

wifiP2pInfo.groupOwnerAddress.getHostAddress());

StringBuilder stringBuilder = new StringBuilder();

if

(mWifiP2pDevice != null) {

stringBuilder.append("连接的设备名：");

stringBuilder.append(mWifiP2pDevice.deviceName);

stringBuilder.append("\n");

stringBuilder.append("连接的设备的地址：");

stringBuilder.append(mWifiP2pDevice.deviceAddress);

}

stringBuilder.append("\n");

stringBuilder.append("是否群主：");

stringBuilder.append(wifiP2pInfo.isGroupOwner ? "是群主" :

"非群主");

stringBuilder.append("\n");

stringBuilder.append("群主IP地址：");

stringBuilder.append(wifiP2pInfo.groupOwnerAddress.getHostAddress());

tv_status.setText(stringBuilder);

if

(wifiP2pInfo.groupFormed && !wifiP2pInfo.isGroupOwner)

{

this.wifiP2pInfo =

wifiP2pInfo;

}

}

至此服务器端和客户端已经通过 Wifi P2P

连接在了一起，客户端也获取到了服务器端的IP地址，在选取好待发送的文件后就可以主动发起对服务器端的连接请求了

发起选取文件的方法

Intent intent = new

Intent(Intent.ACTION_GET_CONTENT);

intent.setType("*

public class WifiClientTask extends AsyncTask

{

private

ProgressDialog progressDialog;

private

FileTransfer fileTransfer;

private

static final int PORT = 4786;

private

static final String TAG = "WifiClientTask";

public

WifiClientTask(Context context, FileTransfer fileTransfer)

{

this.fileTransfer =

fileTransfer;

progressDialog = new

ProgressDialog(context);

progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);

progressDialog.setCancelable(false);

progressDialog.setCanceledOnTouchOutside(false);

progressDialog.setTitle("正在发送文件");

progressDialog.setMax(100);

}

@Override

protected

void onPreExecute() {

progressDialog.show();

}

@Override

protected

Boolean doInBackground(String... strings) {

fileTransfer.setMd5(Md5Util.getMd5(new

File(fileTransfer.getFilePath())));

Log.e(TAG, "文件的MD5码值是：" +

fileTransfer.getMd5());

Socket socket =

null;

OutputStream outputStream =

null;

ObjectOutputStream

objectOutputStream = null;

InputStream inputStream =

null;

try {

socket = new Socket();

socket.bind(null);

socket.connect((new

InetSocketAddress(strings[0], PORT)), 10000);

outputStream =

socket.getOutputStream();

objectOutputStream = new

ObjectOutputStream(outputStream);

objectOutputStream.writeObject(fileTransfer);

inputStream = new FileInputStream(new

File(fileTransfer.getFilePath()));

long fileSize =

fileTransfer.getFileLength();

long total = 0;

byte buf[] = new byte[512];

int len;

while ((len = inputStream.read(buf)) != -1)

{

outputStream.write(buf, 0, len);

total +=

len;

int

progress = (int) ((total * 100) / fileSize);

publishProgress(progress);

Log.e(TAG,

"文件发送进度：" + progress);

}

outputStream.close();

objectOutputStream.close();

inputStream.close();

socket.close();

outputStream = null;

objectOutputStream = null;

inputStream = null;

socket = null;

Log.e(TAG, "文件发送成功");

return true;

} catch (Exception e)

{

Log.e(TAG, "文件发送异常 Exception: " +

e.getMessage());

} finally {

if (outputStream != null) {

try

{

outputStream.close();

} catch

(IOException e) {

e.printStackTrace();

}

}

if (objectOutputStream != null) {

try

{

objectOutputStream.close();

} catch

(IOException e) {

e.printStackTrace();

}

}

if (inputStream != null) {

try

{

inputStream.close();

} catch

(IOException e) {

e.printStackTrace();

}

}

if (socket != null) {

try

{

socket.close();

} catch

(Exception e) {

e.printStackTrace();

}

}

}

return false;

}

@Override

protected

void onProgressUpdate(Integer... values) {

progressDialog.setProgress(values[0]);

}

@Override

protected

void onPostExecute(Boolean aBoolean) {

progressDialog.cancel();

Log.e(TAG, "onPostExecute: "

+ aBoolean);

}

}

五、校验文件完整性

传输文件的完整性主要是通过计算文件的MD5码值来保证了，在发送文件前，即在 WifiClientTask 的

doInBackground 方法中进行计算，将MD5码值赋给 FileTransfer 模型，通过如下方法计算得到

public class Md5Util {

public

static String getMd5(File file) {

InputStream inputStream =

null;

byte[] buffer = new

byte[2048];

int numRead;

MessageDigest md5;

try {

inputStream = new

FileInputStream(file);

md5 =

MessageDigest.getInstance("MD5");

while ((numRead = inputStream.read(buffer)) >

0) {

md5.update(buffer, 0, numRead);

}

inputStream.close();

inputStream = null;

return md5ToString(md5.digest());

} catch (Exception e)

{

return null;

} finally {

if (inputStream != null) {

try

{

inputStream.close();

} catch

(IOException e) {

e.printStackTrace();

}

}

}

}

private

static String md5ToString(byte[] md5Bytes) {

StringBuilder hexValue = new

StringBuilder();

for (byte b : md5Bytes)

{

int val = ((int) b) & 0xff;

if (val < 16) {

hexValue.append("0");

}

hexValue.append(Integer.toHexString(val));

}

return

hexValue.toString();

}

}

因为客户端会将 FileTransfer

传给服务器端，所以服务器端在文件传输结束后，可以重新计算文件的MD5码值，进行对比以判断文件是否完整