我想创建一个非常简单的android UDP Uni cast 服务器和一个C＃UDP客户端。我们可以在android上创建服务器吗？如果是，那么应该给c＃客户端提供哪个IP地址与android服务器连接？
编辑：我在Android上完成了Uni-cast UDP服务器，在C＃中完成了单播UDP客户端。 服务器正在发送DatagramPackets，客户端正在成功接收。但相反的情况并没有发生，并且没有任何错误和例外。但我无法理解代码中的问题是什么。
Android服务器：
public class MainActivity extends Activity {
String myIP;
final Integer myPort = 12345;
String clientIP = "192.168.1.3";
Integer clientPort = 54321;
byte[] inBuffer,outBuffer;
Button send, set;
EditText sendMsg, receiveMsg, cip, cp;
DatagramSocket me;
AsyncTask<Void, byte[], Void> asyncReceiver;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
send = (Button) findViewById(R.id.button1);
sendMsg = (EditText) findViewById(R.id.editText1);
receiveMsg = (EditText) findViewById(R.id.editText2);
set = (Button) findViewById(R.id.button2);
cip = (EditText) findViewById(R.id.editText3);
cp = (EditText) findViewById(R.id.editText4);
inBuffer = new byte[256];
outBuffer = new byte[256];
myIP = null;
myIP = GetCurrentIP();
if (myIP == null) {
Msg("GetCurrentIP error.");
} else {
try {
setTitle(myIP+"|"+InetAddress.getLocalHost());
} catch (UnknownHostException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
if (!Bind()) {
Msg("Bind() error.");
} else {
set.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
clientIP = cip.getText().toString();
clientPort = Integer.parseInt(cp.getText().toString());
Msg(clientIP+"|"+clientPort);
}
});
send.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
outBuffer = sendMsg.getText().toString().getBytes();
SendToClient();
}
});
//-----------
asyncReceiver = new AsyncTask<Void, byte[], Void>() {
@Override
protected void onProgressUpdate(byte[]... values) {
// TODO Auto-generated method stub
super.onProgressUpdate(values);
receiveMsg.append(new String(values[0]));
}
@Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
try {
while(true){
inBuffer = new byte[256];
DatagramPacket pack = new DatagramPacket(inBuffer, inBuffer.length, InetAddress.getByName(clientIP), clientPort);
me.receive(pack);
publishProgress(inBuffer);
Thread.sleep(500);
}
} catch (Exception e) {
// TODO: handle exception
Msg(e.getMessage());
}
return null;
}
};
//-----------
asyncReceiver.execute(new Void[1]);
Msg("Receiving started.");
}
}
}
private void SendToClient(){
try {
DatagramPacket pack = new DatagramPacket(outBuffer, outBuffer.length, InetAddress.getByName(clientIP), clientPort);
me.send(pack);
Msg("Sent successfully.");
} catch (Exception e) {
// TODO: handle exception
Msg(e.getMessage());
}
}
private boolean Bind(){
try {
// DatagramChannel channel = DatagramChannel.open();
// me = channel.socket();
// //me = new DatagramSocket();
// SocketAddress localAddr = new InetSocketAddress(InetAddress.getByName(myIP), myPort);
// me.bind(localAddr);
me = new DatagramSocket(myPort, InetAddress.getByName(myIP));
Msg("Bound Successfully.");
return true;
} catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Msg(e.getMessage());
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Msg(e.getMessage());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return false;
}
private String GetCurrentIP(){
WifiManager wifiMgr = (WifiManager) getSystemService(WIFI_SERVICE);
return Formatter.formatIpAddress(wifiMgr.getConnectionInfo().getIpAddress());
}
public void Msg(String msg){
Toast.makeText(getApplicationContext(), msg, Toast.LENGTH_SHORT).show();
Log.v(">>>>>", msg);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
c＃client ...
public partial class Form1 : Form
{
Socket me;
EndPoint myEndPoint;
byte[] inBuffer, outBuffer;
EndPoint serverEP;
private void SendToClient()
{
if (serverEP == null)
{
serverEP = new IPEndPoint(IPAddress.Parse(textBoxsip.Text), int.Parse(textBoxsp.Text));
}
try
{
lock (me)
{
outBuffer = new byte[256];
outBuffer = Encoding.Default.GetBytes(textBoxmsg.Text);
me.SendTo(outBuffer, serverEP);
}
Task.Run(() => MessageBox.Show("Sent"));
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private String GetCurrentIP()
{
IPAddress[] ips = Dns.GetHostAddresses(Dns.GetHostName());
var selectedIPs = from ip in ips
where ip.AddressFamily == AddressFamily.InterNetwork
select ip;
return selectedIPs.First().ToString();
}
public Form1()
{
InitializeComponent();
inBuffer = new byte[256];
outBuffer = new byte[256];
}
private void Form1_Load(object sender, EventArgs e)
{
this.Text = GetCurrentIP();
me = new Socket
(
AddressFamily.InterNetwork,
SocketType.Dgram,
ProtocolType.Udp
);
}
private void buttonBind_Click(object sender, EventArgs e)
{
try
{
myEndPoint = new IPEndPoint(IPAddress.Parse(textBoxBip.Text), int.Parse(textBoxBp.Text));
me.Bind(myEndPoint);
Task.Run(()=> MessageBox.Show("Bound Successfully."));
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void buttonReceiveFrom_Click(object sender, EventArgs e)
{
if (serverEP == null)
{
serverEP = new IPEndPoint(IPAddress.Parse(textBoxsip.Text), int.Parse(textBoxsp.Text));
}
try
{
me.BeginReceiveFrom
(
inBuffer,
0,
inBuffer.Length,
SocketFlags.None,
ref serverEP,
new AsyncCallback(onReceiveComplete),
null
);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void onReceiveComplete(IAsyncResult ar)
{
try
{
int nobs = me.EndReceiveFrom(ar, ref serverEP);
if (nobs > 0)
{
AddtoListBox(Encoding.Default.GetString(inBuffer));
}
inBuffer = new byte[256];
me.BeginReceiveFrom
(
inBuffer,
0,
inBuffer.Length,
SocketFlags.None,
ref serverEP,
new AsyncCallback(onReceiveComplete),
null
);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void AddtoListBox(String msg)
{
this.Invoke((Action)delegate(){listBox1.Items.Add(msg);});
}
private void buttonSendTo_Click(object sender, EventArgs e)
{
SendToClient();
}
}
}
答案 0 :(得分：0)
这是一个很好的c＃＆lt; - ＆gt; android udp示例： Android client finding C# server automatically
<强> C＃
//receive UDP packet
int port = (int)float.Parse(Variables.port_key);
UdpCient UDP_packet = new UdpClient(port);
UDP_packet.EnableBroadcast = true;
IPEndPoint RemoteIpEndPoint = new IPEndPoint(IPAddress.Any, 0);
IPAddress from_addr = null;
Boolean gogo = false;
while (!gogo)
{
Byte[] receiveBytes = UDP_packet.Receive(ref RemoteIpEndPoint);
string returnData = Encoding.UTF8.GetString(receiveBytes);
if (returnData.ToString() == "83hcX1")
{
gogo = true;
}
from_addr = RemoteIpEndPoint.Address;
}
//send UDP packet
IPEndPoint ipEndPoint = new IPEndPoint(from_addr, port);
Byte[] sendBytes = Encoding.UTF8.GetBytes("94dbF5");
UDP_packet.Send(sendBytes, sendBytes.Length, ipEndPoint);
UDP_packet.Close();
<强>的Android
//send UDP packet
DatagramSocket UDP_packet = new DatagramSocket(SERVERPORT);
UDP_packet.setBroadcast(true);
byte[] b = "83hcX1".getBytes("UTF-8");
DatagramPacket outgoing = new DatagramPacket(b, b.length, getBroadcastAddress(Main.this), SERVERPORT);
UDP_packet.send(outgoing);
//receive UDP packet
boolean gogo = false;
while (!gogo) {
byte[] buffer = new byte[1024];
DatagramPacket incoming = new DatagramPacket(buffer, buffer.length);
UDP_packet.receive(incoming);
String message = new String(incoming.getData(), 0, incoming.getLength(), "UTF-8");
if (message.equals("94dbF5")) {
gogo = true;
SERVER_IP = incoming.getAddress();
}
}
UDP_packet.close();
InetAddress getBroadcastAddress(Context context) throws IOException {
WifiManager wifi = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
DhcpInfo dhcp = wifi.getDhcpInfo();
if (dhcp == null) {
return null;
}
int broadcast = (dhcp.ipAddress & dhcp.netmask) | ~dhcp.netmask;
byte[] quads = new byte[4];
for (int k = 0; k < 4; k++)
quads[k] = (byte) ((broadcast >> k * 8) & 0xFF);
return InetAddress.getByAddress(quads);
}
某些路由器（可能是5％）阻止UDP广播，所以......小心。
获取Android（服务器）IP：
InetAddress getBroadcastAddress(Context context) throws IOException {
WifiManager wifi = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
DhcpInfo dhcp = wifi.getDhcpInfo();
if (dhcp == null) {
return null;
}
int broadcast = (dhcp.ipAddress & dhcp.netmask) | ~dhcp.netmask;
byte[] quads = new byte[4];
for (int k = 0; k < 4; k++)
quads[k] = (byte) ((broadcast >> k * 8) & 0xFF);
return InetAddress.getByAddress(quads);
}