我正在尝试在galaxy tab和laptop之间建立联系。所以我试图在我的笔记本电脑和客户端活动上运行服务器活动，但它不起作用。这是服务器和客户端代码。错误在哪里？
服务器：
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView txt = (TextView)findViewById(R.id.textView1);
int port = 12345;
byte [] message = new byte [1500];
DatagramPacket p = new DatagramPacket (message,message.length);
try {
InetAddress serveraddr = InetAddress.getByName("192.168.1.116");
DatagramSocket s = new DatagramSocket (port,serveraddr);
while (true){
s.receive(p);
String text = new String (message,0,p.getLength());
txt.setText(text);
}
} catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
客户：
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final EditText edt = (EditText)findViewById(R.id.editText1);
Button btn = (Button)findViewById(R.id.button1);
btn.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
String msg = edt.getText().toString();
int port = 12345;
try {
DatagramSocket s = new DatagramSocket();
InetAddress local = InetAddress.getByName("192.168.1.116");
int msg_lenght = msg.length();
byte []message = msg.getBytes();
DatagramPacket p = new DatagramPacket(message,msg_lenght,local,port);
s.send(p);
} catch (SocketException e) {
e.printStackTrace();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
});
}
以下是日志：
09-17 23:49:55.190: D/dalvikvm(5892): Late-enabling CheckJNI
09-17 23:49:55.690: D/CLIPBOARD(5892): Hide Clipboard dialog at Starting input: finished by someone else... !
09-17 23:49:59.590: D/AndroidRuntime(5892): Shutting down VM
09-17 23:49:59.590: W/dalvikvm(5892): threadid=1: thread exiting with uncaught exception (group=0x40c4f1f8)
09-17 23:49:59.590: E/AndroidRuntime(5892): FATAL EXCEPTION: main
09-17 23:49:59.590: E/AndroidRuntime(5892): android.os.NetworkOnMainThreadException
09-17 23:49:59.590: E/AndroidRuntime(5892): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1099)
09-17 23:49:59.590: E/AndroidRuntime(5892): at libcore.io.BlockGuardOs.sendto(BlockGuardOs.java:175)
09-17 23:49:59.590: E/AndroidRuntime(5892): at libcore.io.IoBridge.sendto(IoBridge.java:463)
09-17 23:49:59.590: E/AndroidRuntime(5892): at java.net.PlainDatagramSocketImpl.send(PlainDatagramSocketImpl.java:182)
09-17 23:49:59.590: E/AndroidRuntime(5892): at java.net.DatagramSocket.send(DatagramSocket.java:307)
09-17 23:49:59.590: E/AndroidRuntime(5892): at com.example.udpclient.MainActivity$1.onClick(MainActivity.java:36)
09-17 23:49:59.590: E/AndroidRuntime(5892): at android.view.View.performClick(View.java:3620)
09-17 23:49:59.590: E/AndroidRuntime(5892): at android.view.View$PerformClick.run(View.java:14322)
09-17 23:49:59.590: E/AndroidRuntime(5892): at android.os.Handler.handleCallback(Handler.java:605)
09-17 23:49:59.590: E/AndroidRuntime(5892): at android.os.Handler.dispatchMessage(Handler.java:92)
09-17 23:49:59.590: E/AndroidRuntime(5892): at android.os.Looper.loop(Looper.java:137)
09-17 23:49:59.590: E/AndroidRuntime(5892): at android.app.ActivityThread.main(ActivityThread.java:4507)
09-17 23:49:59.590: E/AndroidRuntime(5892): at java.lang.reflect.Method.invokeNative(Native Method)
09-17 23:49:59.590: E/AndroidRuntime(5892): at java.lang.reflect.Method.invoke(Method.java:511)
09-17 23:49:59.590: E/AndroidRuntime(5892): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:978)
09-17 23:49:59.590: E/AndroidRuntime(5892): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:745)
09-17 23:49:59.590: E/AndroidRuntime(5892): at dalvik.system.NativeStart.main(Native Method)
09-17 23:50:34.320: I/Process(5892): Sending signal. PID: 5892 SIG: 9
答案 0 :(得分：4)
09-17 23:49:59.590: E/AndroidRuntime(5892): android.os.NetworkOnMainThreadException
09-17 23:49:59.590: E/AndroidRuntime(5892): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1099)
09-17 23:49:59.590: E/AndroidRuntime(5892): at libcore.io.BlockGuardOs.sendto(BlockGuardOs.java:175)
您不应该在ui线程中执行网络或时间加强操作
另见： Android: NoClassDefFoundError for some app users或 android developers information
结帐： activity.runOnUi
答案 1 :(得分：0)
您在服务器的onCreate中有一个无限循环。你不应该！创建一个用于轮询套接字的线程。
答案 2 :(得分：0)
您的代码有2个问题
09-17 23：49：59.590：E / AndroidRuntime（5892）：致命异常：主要 09-17 23：49：59.590：E / AndroidRuntime（5892）： android.os.NetworkOnMainThreadException
while (true){ s.receive(p); String text = new String (message,0,p.getLength()); txt.setText(text); }
答案 3 :(得分：0)
快速解决方案......
创建一个udpOutputData字符串：
String udpOutputData;
在代码中创建一个新主题：
//-----UDP send thread
Thread udpSendThread = new Thread(new Runnable() {
@Override
public void run() {
while (true) {
try {
Thread.sleep(100);
}
catch (InterruptedException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
if (sendUdp == true) {
try {
// get server name
InetAddress serverAddr = InetAddress.getByName(outputIP);
Log.d("UDP", "C: Connecting...");
// create new UDP socket
DatagramSocket socket = new DatagramSocket();
// prepare data to be sent
byte[] buf = udpOutputData.getBytes();
// create a UDP packet with data and its destination ip & port
DatagramPacket packet = new DatagramPacket(buf, buf.length, serverAddr, broadcastPort);
Log.d("UDP", "C: Sending: '" + new String(buf) + "'");
// send the UDP packet
socket.send(packet);
socket.close();
Log.d("UDP", "C: Sent.");
Log.d("UDP", "C: Done.");
}
catch (Exception e) {
Log.e("UDP", "C: Error", e);
}
try {
Thread.sleep(100);
}
catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
sendUdp = false;
}
}
}
});
创建一个方法，以便每次要发送一些udp数据时调用：
public void sendUdp(String udpMsg) {
udpOutputData = udpMsg;
sendUdp = true;
}
每次要发送udp数据包时，都会调用该方法并为输出数据传递一个字符串：
String s = "hello from app";
sendUdp(s);