Question

我坚持在通过wifi创建Android手机（2.3）和我的电脑之间的UDP连接。

我知道如何在本地服务器中创建UDP连接。我的问题是做android支持adhock网络，因为每当我尝试直接搜索我的PC的wifi时，它都没有显示它，因此我必须首先在我的PC上创建一个虚拟热点，然后将我的手机连接到它。

在此之后，我只是尝试将数据包从手机发送到PC上运行的服务器。

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);
}

}

在我的电脑上运行的服务器代码：

    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);
        }

}

客户端代码（WifiTestActivity）出错，每当我尝试在手机上运行时，我的应用都会崩溃。 Plzz帮助我！

Answer 1

您需要Internet Permission。将此添加到您的清单：

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

udp连接通过wifi android

1 个答案: