我正在使用套接字（TCP连接）在两个Android设备之间做一个简单的聊天应用程序问题是它只能在局域网上工作，但不能通过WAN工作如何解决这个问题？ 客户机侧::
public class MainActivity extends AppCompatActivity {
TextView tv_device, tv_receive, tv_transmit;
Button btn_connect, btn_GPS;
EditText et_IP_Address, et_port, et_message;
Socket S;
DataOutputStream DOS;
DataOutputStream DOS2;
DataInputStream DIS;
Thread TH;
Thread TH2;
String data;
int q=0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
et_IP_Address= (EditText) findViewById(R.id.et_IP_Address);
et_port= (EditText) findViewById(R.id.et_port);
et_message= (EditText) findViewById(R.id.et_message);
et_message.setText("GPS");
btn_connect = (Button) findViewById(R.id.btn_connect);
btn_GPS= (Button) findViewById(R.id.btn_send);
tv_transmit=(TextView) findViewById(R.id.tv_transmit);
tv_receive = (TextView) findViewById(R.id.tv_receive);
tv_device = (TextView) findViewById(R.id.tv_device);
// connection
btn_connect.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
TH=new Thread(new Runnable() {
@Override
public void run() {
try {
S = new Socket(et_IP_Address.getText().toString(),Integer.parseInt(et_port.getText().toString()));
DOS = new DataOutputStream(S.getOutputStream());
} catch (IOException e) {
e.printStackTrace();
}
}
});// End of thread
TH.start();
}
}); // end of buutton
// Sending
btn_GPS.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
TH2=new Thread(new Runnable() {
@Override
public void run() {
while (!Thread.currentThread().isInterrupted()) {
try {
DOS2 = new DataOutputStream(S.getOutputStream());
DOS2.writeUTF(et_message.getText().toString());
} catch (IOException e) {
e.printStackTrace();
}
tv_transmit.post(new Runnable() {
@Override
public void run() {
tv_transmit.setText(et_message.getText());
}
});
try {
DOS2.flush();
} catch (IOException e) {
e.printStackTrace();
}
try {
DIS = new DataInputStream(S.getInputStream());
} catch (IOException e) {
e.printStackTrace();
}
while (DIS!=null) {
try {
data = DIS.readUTF();
} catch (IOException e) {
e.printStackTrace();
}
data = data.toString();
tv_receive.post(new Runnable() {
public void run() {
tv_receive.setText(data);
}
});
try {
DOS2.close();
DIS.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}); // end of thread
TH2.start();
}
}); // end of button
}
@Override
protected void onStop() {
super.onStop();
try {
if(S != null)
S.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
服务器端::
public class MainActivity extends AppCompatActivity {
Thread TH;
String data;
Socket S;
ServerSocket ss;
DataOutputStream DOS;
String recieved="GPS";
String Response;
TextView et_port; TextView tv_receive; TextView tv_transmit; TextView status;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
et_port = (TextView) findViewById(R.id.et_port);
tv_receive = (TextView) findViewById(R.id.tv_receive);
tv_transmit = (TextView) findViewById(R.id.tv_transmit);
status = (TextView) findViewById(R.id.status);
Intent intent = new Intent(this, MyService.class);
startService(intent);
establishconnection();
}
public void establishconnection() {
TH = new Thread(new Runnable() {
@Override
public void run() {
status.setText(MyService.getIpAddress());
try {
ss = new ServerSocket(8080);
} catch (IOException e) {
e.printStackTrace();
}
while (true) {
try {
S = ss.accept();
} catch (IOException e) {
e.printStackTrace();
}
status.post(new Runnable() {
@Override
public void run() {
status.setText("connected");
}
}
);
CommunicationThread commThread = null;
try {
commThread = new CommunicationThread(S);
} catch (IOException e) {
e.printStackTrace();
}
new Thread(commThread).start();
}
}
});
TH.start();
}
class CommunicationThread implements Runnable {
private Socket ClientSocket;
DataInputStream DIS;
public CommunicationThread(Socket ClientSocket) throws IOException {
this.ClientSocket = ClientSocket;
DIS = new DataInputStream(ClientSocket.getInputStream());
data = DIS.readUTF();
}
public void run() {
while (!Thread.currentThread().isInterrupted()) {
data = data.toString();
tv_receive.post(new Runnable() {
public void run() {
tv_receive.setText(data);
}
});
while (recieved.equals(data)) {
sendMessage();
try {
DOS = new DataOutputStream(S.getOutputStream());
} catch (IOException e) {
e.printStackTrace();
}
try {
Thread.sleep(8000);
} catch (InterruptedException e) {
e.printStackTrace();
}
try {
if (Response !=null){
DOS.writeUTF(Response);
}
} catch (IOException e) {
e.printStackTrace();
}
tv_transmit.post(new Runnable() {
@Override
public void run() {
tv_transmit.setText(Response);
}
});
try {
DOS.flush();
DOS.close();
} catch (IOException e) {
e.printStackTrace();
}
}
try {
S.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
public void sendMessage() {
Intent i = new Intent(this,Gps.class);
startActivityForResult(i, 1);
}
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == 1) {
if(resultCode == RESULT_OK) {
// Bundle bundle = getIntent().getExtras();
if (data!=null) {
String x = data.getStringExtra("Latitude");
String y = data.getStringExtra("Longitude");
Response = x + "\n" + y;
}
}
}
}
}
这里客户端假设在服务器收到它时向服务器发送一个字，它将打开另一个意图并将一些数据“GPS”返还给客户端