通過wifi android的udp連接

Question

我被困在通過wifi在android手機（2.3）和我的PC之間創建UDP連接。

我知道如何在本地服務器中創建UDP連接。 我的問題是android是否支持輔助網絡，因為每當我嘗試直接搜索PC的wifi時，它都不會顯示它，因此我必須先在PC上創建一個虛擬熱點，然后將手機連接到它。

之后，我只是嘗試將數據包從手機發送到PC上運行的服務器。

public class WifitestActivity extends Activity {
    WifiManager w;
    TextView status;
    InetAddress server_ip;
    int server_port = 9876;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    status = (TextView) findViewById(R.id.status);

    w = (WifiManager) this.getSystemService(Context.WIFI_SERVICE);

    if (!w.isWifiEnabled()) {
        status.setText("switching ON wifi ");
        w.setWifiEnabled(true);
    } else {
        status.setText("Its already ON ");

    }

    int x;
    WifiInfo info = w.getConnectionInfo();
    status.append("\n\nWiFi Status: " + info.toString());

    x = info.getIpAddress();
    String str = info.getMacAddress();

    status.append("\n\nmac address===" + str + "  ,ip===" + x);

    try {
        server_ip = InetAddress.getByName("192.168.181.1"); // ip of my server.How to dynamically update it
    } catch (UnknownHostException e) {
        status.append("Error at fetching inetAddress");
    }

    DatagramSocket s = new DatagramSocket(server_port, server_ip);
    // **ERROR AT PREVIOUS LINE, I HAD TO FORCE STOP MY APP EVERTIME I RUN
    // MY CODE**
    String str = "TEST MESSAGE !!!";
    byte b1[];
    b1 = new byte[100];
    b1 = str.getBytes();
    DatagramPacket p1 = new DatagramPacket(b1, b1.length, server_ip,
            server_port);
}

}

我的PC上運行的服務器代碼：

    import java.io.*;
    import java.net.*;
    class server2
    {
        static InetAddress clientip;
        static int clientport;
        static DatagramPacket p3;

        public static void main(String args[])throws Exception
        {

        DatagramSocket s = new DatagramSocket(9876);

        byte b1[],b2[];
        b1=new byte[100];
        b2=new byte[100];

        DatagramPacket p1 = new DatagramPacket(b1,b1.length);
        s.receive(p1);

        b1=p1.getData();
        String str = new String( b1);

        clientport = p1.getPort();  //packet mein save hota hai 
        clientip=p1.getAddress();

        System.out.println("RECIEVED FROM CLIENT IP ="+clientip+" port="+clientport+" data="+str);
        }

}

客戶端代碼（WifiTestActivity）發生錯誤，並且每當我嘗試在手機上運行該應用程序時，該應用程序就會崩潰。 請幫我！

Answer 1

您需要Internet許可 。 將此添加到您的清單：

<uses-permission android:name="android.permission.INTERNET"/>