我需要通过WiFi-Direct从传感器获取数据。如何向传感器发送命令？
问题描述：
我一直在研究这个项目，我应该使用WiFi Direct将我的手机连接到传感器。然后检索传感器数据并在地图上将其可视化。我已经能够使用WiFi Direct将传感器连接到手机，并在地图上的infowindow中将虚假数据可视化。制造传感器的公司应该提供给我数据的命令。我被卡在需要与传感器建立连接并发送命令的部分。我需要通过WiFi-Direct从传感器获取数据。如何向传感器发送命令？
我正在看这款适用于WiFi-direct的演示应用程序，该应用程序应该在两个设备之间发送图像。我是否可以用某种方式改写它，而不是通过手机发送命令给我的手机而不是图像？如果不是，发送命令到传感器的最简单方法是什么？
我很感激我得到的任何帮助。
以下是传送图像的服务代码。
FileTransferService：
public class FileTransferService extends IntentService {
private static final int SOCKET_TIMEOUT = 5000;
public static final String ACTION_SEND_FILE = "com.example.android.wifidirect.SEND_FILE";
public static final String EXTRAS_FILE_PATH = "file_url";
public static final String EXTRAS_ADDRESS = "go_host";
public static final String EXTRAS_PORT = "go_port";
public FileTransferService(String name) {
super(name);
}
public FileTransferService() {
super("FileTransferService");
}
/*
* (non-Javadoc)
* @see android.app.IntentService#onHandleIntent(android.content.Intent)
*/
@Override
protected void onHandleIntent(Intent intent) {
Context context = getApplicationContext();
if (intent.getAction().equals(ACTION_SEND_FILE)) {
String fileUri = intent.getExtras().getString(EXTRAS_FILE_PATH);
String host = intent.getExtras().getString(EXTRAS_ADDRESS);
Socket socket = new Socket();
int port = intent.getExtras().getInt(EXTRAS_PORT);
try {
Log.d(WiFiDirectActivity.TAG, "Opening client socket - ");
socket.bind(null);
socket.connect((new InetSocketAddress(host, port)), SOCKET_TIMEOUT);
Log.d(WiFiDirectActivity.TAG, "Client socket - " + socket.isConnected());
OutputStream stream = socket.getOutputStream();
ContentResolver cr = context.getContentResolver();
InputStream is = null;
try {
is = cr.openInputStream(Uri.parse(fileUri));
} catch (FileNotFoundException e) {
Log.d(WiFiDirectActivity.TAG, e.toString());
}
DeviceDetailFragment.copyFile(is, stream);
Log.d(WiFiDirectActivity.TAG, "Client: Data written");
} catch (IOException e) {
Log.e(WiFiDirectActivity.TAG, e.getMessage());
} finally {
if (socket != null) {
if (socket.isConnected()) {
try {
socket.close();
} catch (IOException e) {
// Give up
e.printStackTrace();
}
}
}
}
}
}
}
DeviceDetailFragment
public class DeviceDetailFragment extends Fragment implements ConnectionInfoListener {
public static final String IP_SERVER = "192.168.49.1";
public static int PORT = 8988;
private static boolean server_running = false;
protected static final int CHOOSE_FILE_RESULT_CODE = 20;
private View mContentView = null;
private WifiP2pDevice device;
private WifiP2pInfo info;
ProgressDialog progressDialog = null;
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
mContentView = inflater.inflate(R.layout.device_detail, null);
mContentView.findViewById(R.id.btn_connect).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
WifiP2pConfig config = new WifiP2pConfig();
config.deviceAddress = device.deviceAddress;
config.wps.setup = WpsInfo.PBC;
if (progressDialog != null && progressDialog.isShowing()) {
progressDialog.dismiss();
}
progressDialog = ProgressDialog.show(getActivity(), "Press back to cancel",
"Connecting to :" + device.deviceAddress, true, true
// new DialogInterface.OnCancelListener() {
//
// @Override
// public void onCancel(DialogInterface dialog) {
// ((DeviceActionListener) getActivity()).cancelDisconnect();
// }
// }
);
((DeviceActionListener) getActivity()).connect(config);
}
});
mContentView.findViewById(R.id.btn_disconnect).setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
((DeviceActionListener) getActivity()).disconnect();
}
});
mContentView.findViewById(R.id.btn_start_client).setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
// Allow user to pick an image from Gallery or other
// registered apps
Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
intent.setType("image/*");
startActivityForResult(intent, CHOOSE_FILE_RESULT_CODE);
}
});
return mContentView;
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
String localIP = Utils.getLocalIPAddress();
// Trick to find the ip in the file /proc/net/arp
String client_mac_fixed = new String(device.deviceAddress).replace("99", "19");
String clientIP = Utils.getIPFromMac(client_mac_fixed);
// User has picked an image. Transfer it to group owner i.e peer using
// FileTransferService.
Uri uri = data.getData();
TextView statusText = (TextView) mContentView.findViewById(R.id.status_text);
statusText.setText("Sending: " + uri);
Log.d(WiFiDirectActivity.TAG, "Intent----------- " + uri);
Intent serviceIntent = new Intent(getActivity(), FileTransferService.class);
serviceIntent.setAction(FileTransferService.ACTION_SEND_FILE);
serviceIntent.putExtra(FileTransferService.EXTRAS_FILE_PATH, uri.toString());
if(localIP.equals(IP_SERVER)){
serviceIntent.putExtra(FileTransferService.EXTRAS_ADDRESS, clientIP);
}else{
serviceIntent.putExtra(FileTransferService.EXTRAS_ADDRESS, IP_SERVER);
}
serviceIntent.putExtra(FileTransferService.EXTRAS_PORT, PORT);
getActivity().startService(serviceIntent);
}
@Override
public void onConnectionInfoAvailable(final WifiP2pInfo info) {
if (progressDialog != null && progressDialog.isShowing()) {
progressDialog.dismiss();
}
this.info = info;
this.getView().setVisibility(View.VISIBLE);
// The owner IP is now known.
TextView view = (TextView) mContentView.findViewById(R.id.group_owner);
view.setText(getResources().getString(R.string.group_owner_text)
+ ((info.isGroupOwner == true) ? getResources().getString(R.string.yes)
: getResources().getString(R.string.no)));
// InetAddress from WifiP2pInfo struct.
view = (TextView) mContentView.findViewById(R.id.device_info);
view.setText("Group Owner IP - " + info.groupOwnerAddress.getHostAddress());
mContentView.findViewById(R.id.btn_start_client).setVisibility(View.VISIBLE);
if (!server_running){
new ServerAsyncTask(getActivity(), mContentView.findViewById(R.id.status_text)).execute();
server_running = true;
}
// hide the connect button
mContentView.findViewById(R.id.btn_connect).setVisibility(View.GONE);
}
/**
* Updates the UI with device data
*
* @param device the device to be displayed
*/
public void showDetails(WifiP2pDevice device) {
this.device = device;
this.getView().setVisibility(View.VISIBLE);
TextView view = (TextView) mContentView.findViewById(R.id.device_address);
view.setText(device.deviceAddress);
view = (TextView) mContentView.findViewById(R.id.device_info);
view.setText(device.toString());
}
/**
* Clears the UI fields after a disconnect or direct mode disable operation.
*/
public void resetViews() {
mContentView.findViewById(R.id.btn_connect).setVisibility(View.VISIBLE);
TextView view = (TextView) mContentView.findViewById(R.id.device_address);
view.setText(R.string.empty);
view = (TextView) mContentView.findViewById(R.id.device_info);
view.setText(R.string.empty);
view = (TextView) mContentView.findViewById(R.id.group_owner);
view.setText(R.string.empty);
view = (TextView) mContentView.findViewById(R.id.status_text);
view.setText(R.string.empty);
mContentView.findViewById(R.id.btn_start_client).setVisibility(View.GONE);
this.getView().setVisibility(View.GONE);
}
/**
* A simple server socket that accepts connection and writes some data on
* the stream.
*/
public static class ServerAsyncTask extends AsyncTask<Void, Void, String> {
private final Context context;
private final TextView statusText;
/**
* @param context
* @param statusText
*/
public ServerAsyncTask(Context context, View statusText) {
this.context = context;
this.statusText = (TextView) statusText;
}
@Override
protected String doInBackground(Void... params) {
try {
ServerSocket serverSocket = new ServerSocket(PORT);
Log.d(WiFiDirectActivity.TAG, "Server: Socket opened");
Socket client = serverSocket.accept();
Log.d(WiFiDirectActivity.TAG, "Server: connection done");
final File f = new File(Environment.getExternalStorageDirectory() + "/"
+ context.getPackageName() + "/wifip2pshared-" + System.currentTimeMillis()
+ ".jpg");
File dirs = new File(f.getParent());
if (!dirs.exists())
dirs.mkdirs();
f.createNewFile();
Log.d(WiFiDirectActivity.TAG, "server: copying files " + f.toString());
InputStream inputstream = client.getInputStream();
copyFile(inputstream, new FileOutputStream(f));
serverSocket.close();
server_running = false;
return f.getAbsolutePath();
} catch (IOException e) {
Log.e(WiFiDirectActivity.TAG, e.getMessage());
return null;
}
}
/*
* (non-Javadoc)
* @see android.os.AsyncTask#onPostExecute(java.lang.Object)
*/
@Override
protected void onPostExecute(String result) {
if (result != null) {
statusText.setText("File copied - " + result);
Intent intent = new Intent();
intent.setAction(android.content.Intent.ACTION_VIEW);
intent.setDataAndType(Uri.parse("file://" + result), "image/*");
context.startActivity(intent);
}
}
/*
* (non-Javadoc)
* @see android.os.AsyncTask#onPreExecute()
*/
@Override
protected void onPreExecute() {
statusText.setText("Opening a server socket");
}
}
public static boolean copyFile(InputStream inputStream, OutputStream out) {
byte buf[] = new byte[1024];
int len;
try {
while ((len = inputStream.read(buf)) != -1) {
out.write(buf, 0, len);
}
out.close();
inputStream.close();
} catch (IOException e) {
Log.d(WiFiDirectActivity.TAG, e.toString());
return false;
}
return true;
}
}
utils的：
public class Utils {
private final static String p2pInt = "p2p-p2p0";
public static String getIPFromMac(String MAC) {
/*
* method modified from:
*
* http://www.flattermann.net/2011/02/android-howto-find-the-hardware-mac-address-of-a-remote-host/
*
* */
BufferedReader br = null;
try {
br = new BufferedReader(new FileReader("/proc/net/arp"));
String line;
while ((line = br.readLine()) != null) {
String[] splitted = line.split(" +");
if (splitted != null && splitted.length >= 4) {
// Basic sanity check
String device = splitted[5];
if (device.matches(".*" +p2pInt+ ".*")){
String mac = splitted[3];
if (mac.matches(MAC)) {
return splitted[0];
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}
public static String getLocalIPAddress() {
/*
* modified from:
*
* http://thinkandroid.wordpress.com/2010/03/27/incorporating-socket-programming-into-your-applications/
*
* */
try {
for (Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces(); en.hasMoreElements();) {
NetworkInterface intf = en.nextElement();
for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); enumIpAddr.hasMoreElements();) {
InetAddress inetAddress = enumIpAddr.nextElement();
String iface = intf.getName();
if(iface.matches(".*" +p2pInt+ ".*")){
if (inetAddress instanceof Inet4Address) { // fix for Galaxy Nexus. IPv4 is easy to use :-)
return getDottedDecimalIP(inetAddress.getAddress());
}
}
}
}
} catch (SocketException ex) {
Log.e("AndroidNetworkAddressFactory", "getLocalIPAddress()", ex);
} catch (NullPointerException ex) {
Log.e("AndroidNetworkAddressFactory", "getLocalIPAddress()", ex);
}
return null;
}
private static String getDottedDecimalIP(byte[] ipAddr) {
/*
* ripped from:
*
* http://stackoverflow.com/questions/10053385/how-to-get-each-devices-ip-address-in-wifi-direct-scenario
*
* */
String ipAddrStr = "";
for (int i=0; i<ipAddr.length; i++) {
if (i > 0) {
ipAddrStr += ".";
}
ipAddrStr += ipAddr[i]&0xFF;
}
return ipAddrStr;
}
}
答
你不能只是发送
命令
但是，您可以发送一个字符串，一个int或甚至一个char -simply数据，并将其与交换机或链接进行比较。如果你想要的话，你还可以编写自己的'传输'类并将其序列化，以便一次发送大量信息。