以下代码会导致超时。

它在非 Android Java 上运行良好。怎么了？

 //@Override
public static void run()
{
    //System.out.println ( "Local Machine IP : "+addrStr.toString (  )  ) ;
    HelloWorldActivity.tv.setText("Trace 1");

    try
    {
        // Retrieve the ServerName
        InetAddress serverAddr; //= InetAddress.getByName(Server.SERVERIP);
        InetAddress ias[] = InetAddress.getAllByName(Server.SERVERNAME);
        serverAddr  = ias[0];

        Log.d("UDP", "C: Connecting...");
        /* Create new UDP-Socket */
        DatagramSocket socket = new DatagramSocket();

        /* Prepare some data to be sent. */
        String strQuery="ÿÿÿÿgetservers"+" "+Server.iProtocol+" "+"'all'";
        Log.d("UDP", strQuery);
        //byte[] buf = ("ÿÿÿÿgetservers 68 'all'").getBytes();
        byte[] buf = strQuery.getBytes();

        /* Create UDP-packet with
         * data & destination(url+port) */
        DatagramPacket packet = new DatagramPacket(buf, buf.length,
                                                   serverAddr, Server.SERVERPORT);

        Log.d("UDP", "C: Sending: '" + new String(buf) + "'");

        /* Send out the packet */
        socket.setSoTimeout(5000);
        socket.send(packet);
        Log.d("UDP", "C: Sent.");
        Log.d("UDP", "C: Done.");

        // http://code.google.com/p/android/issues/detail?id=2917

        byte[] buffer= new byte[1024*100];
        DatagramPacket receivePacket
          = new DatagramPacket(buffer,
                               buffer.length); //, serverAddr, Server.SERVERPORT);
        socket.receive(receivePacket);
        HelloWorldActivity.tv.setText("TTT");

        String x = new String(receivePacket.getData());
        Log.d("UDP", "C: Received: '" + x  + "'");
        HelloWorldActivity.tv.setText(x);

   } catch (Exception e) {
       HelloWorldActivity.tv.setText(e.getMessage());
       Log.e("UDP", "C: Error", e);
   }
}


public class Server
{
    /*
    //public static java.lang.string SERVERIP;
    public static String SERVERNAME = "monster.idsoftware.com";
    public static String SERVERIP = "192.246.40.56";
    public static int SERVERPORT = 27950;
    public static int PROTOCOL = 68;
      */

    //public static String SERVERNAME="monster.idsoftware.com";
    public static String SERVERNAME="dpmaster.deathmask.net";

    public static String SERVERIP="192.246.40.56";
    public static int SERVERPORT=27950;
    //public static int iProtocol= 68; // Quake3
    public static int iProtocol=71; // OpenArena

}

Android list :

<?xml version="1.0" encoding="utf-8"?>

<use-permission id="android.permission.READ_CONTACTS" />

    <use-permission android:name="android.permission.WRITE_SETTINGS" />
    <uses-permission android:name="android.permission.READ_CONTACTS" />
    <uses-permission android:name="android.permission.CALL_PHONE" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_GPS" />
    <uses-permission android:name="android.permission.ACCESS_MOCK_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.ACCESS_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_ASSISTED_GPS" />
    <uses-permission android:name="android.permission.ACCESS_CELL_ID" />

    <uses-permission android:name="android.permission.RECEIVE_SMS" />
    <uses-permission android:name="android.permission.VIBRATE" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />

<application
        android:icon="@drawable/icon"
        android:label="AAA New Application"
        >
    <activity android:name="HelloWorldActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN"/>
            <category android:name="android.intent.category.LAUNCHER"/>
        </intent-filter>
    </activity>
</application>

最佳答案

你是在模拟器上测试还是在真手机上测试？如果您使用的是模拟器，则需要注意 how networking on the emulator works .最具体地说:

Each instance of the emulator runs behind a virtual router/firewall service that isolates it from your development machine's network interfaces and settings and from the internet. An emulated device can not see your development machine or other emulator instances on the network. Instead, it sees only that it is connected through Ethernet to a router/firewall.

您可能需要设置端口转发，using the Emulator console或 using the adb command .

关于java - Android 从不接收 UDP 数据包，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/2101253/