我想创建一个服务器和客户端相互通信的应用程序。代码......
服务器端：
public class MainActivity extends ActionBarActivity {
private ServerSocket serverSocket;
Handler updateConversationHandler;
Thread serverThread = null;
Socket clientSocket;
private TextView text;
EditText edit;
Button b;
public static final int SERVERPORT = 6000;
String TimeStamp;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
System.out.println("inside onCreate");
text = (TextView) findViewById(R.id.textView1);
updateConversationHandler = new Handler();
this.serverThread = new Thread(new ServerThread());
this.serverThread.start();
TimeStamp = new java.util.Date().toString();
b=(Button)findViewById(R.id.button1);
b.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
try
{
EditText et = (EditText) findViewById(R.id.editText1);
String str = et.getText().toString();
text.setText(text.getText().toString()+"Me: "+ str +" On "+TimeStamp+ "\n");
/*
BufferedOutputStream bos=new BufferedOutputStream(socket.getOutputStream());
OutputStreamWriter osw= new OutputStreamWriter(bos,"US-ASCII");
osw.write(str+" "+TimeStamp);
osw.flush();
*/
if(clientSocket==null)
Toast.makeText(MainActivity.this, "null socket", Toast.LENGTH_SHORT).show();
else
{
PrintWriter out = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(clientSocket.getOutputStream())),
true);
out.println(str);
out.flush();
et.setText("");
}
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
@Override
protected void onStop()
{
super.onStop();
try
{
serverSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
class ServerThread implements Runnable
{
public void run()
{
Socket socket = null;
try
{
serverSocket = new ServerSocket(SERVERPORT);
serverSocket.setReuseAddress(true);
} catch (IOException e) {
e.printStackTrace();
}
while (!Thread.currentThread().isInterrupted())
{
try
{
socket = serverSocket.accept();
CommunicationThread commThread = new CommunicationThread(socket);
new Thread(commThread).start();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
class CommunicationThread implements Runnable
{
//private Socket clientSocket;
private BufferedReader input;
public CommunicationThread(Socket aclientSocket)
{
//this.aclientSocket = clientSocket;
clientSocket=aclientSocket;
try {
//this.input = new BufferedReader(new InputStreamReader(this.clientSocket.getInputStream()));
this.input = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
} catch (IOException e) {
e.printStackTrace();
}
}
public void run()
{
while (!Thread.currentThread().isInterrupted())
{
try
{
String read = input.readLine();
updateConversationHandler.post(new updateUIThread(read));
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
class updateUIThread implements Runnable
{
private String msg;
public updateUIThread(String str)
{
this.msg = str;
}
@Override
public void run()
{
text.setText(text.getText().toString()+"Client: "+ msg +" On "+TimeStamp+ "\n");
}
}
}
从客户端发送的消息正确接收到服务器，现在来自服务器的消息写入套接字但无法在客户端读取。
客户端：
public class MainActivity extends ActionBarActivity {
private Socket socket;
Handler updateConversationHandler;
private static final int SERVERPORT = 5000;
private static final String SERVER_IP = "10.0.2.2";
TextView text;
Button c;
String TimeStamp;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new Thread(new ClientThread()).start();
TimeStamp = new java.util.Date().toString();
c=(Button)findViewById(R.id.button1);
text = (TextView) findViewById(R.id.textView1);
c.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
try
{
EditText et = (EditText) findViewById(R.id.editText1);
String str = et.getText().toString();
text.setText(text.getText().toString()+"Me: "+ str +"On "+TimeStamp+ "\n");
PrintWriter out = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())),
true);
out.println(str);
out.flush();
et.setText("");
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
class ClientThread implements Runnable
{
@Override
public void run()
{
try
{
InetAddress serverAddr = InetAddress.getByName(SERVER_IP);
socket = new Socket(serverAddr, SERVERPORT);
CommunicationThread commThread = new CommunicationThread(socket);
new Thread(commThread).start();
} catch (UnknownHostException e1) {
e1.printStackTrace();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
class CommunicationThread implements Runnable
{
private Socket clientSocket;
private BufferedReader input;
public CommunicationThread(Socket clientSocket)
{
this.clientSocket = clientSocket;
try {
this.input = new BufferedReader(new InputStreamReader(this.clientSocket.getInputStream()));
} catch (IOException e) {
e.printStackTrace();
}
}
public void run()
{
while (!Thread.currentThread().isInterrupted())
{
try
{
String read = input.readLine();
Log.d("msg","readString"+read);
updateConversationHandler.post(new updateUIThread(read));
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
class updateUIThread implements Runnable
{
private String msg;
public updateUIThread(String str)
{
this.msg = str;
System.out.println("message in updateThread "+msg);
}
@Override
public void run()
{
System.out.println("message "+msg);
text.setText(text.getText().toString()+"Server: "+ msg +"On "+TimeStamp+ "\n");
}
}
}
logcat显示：
D/gralloc_goldfish(1777): Emulator without GPU emulation detected.
W/System.err(1777): java.lang.NullPointerException
W/System.err(1777): at com.example.socketservereg.MainActivity$1.onClick(MainActivity.java:67)
W/System.err(1777): at android.view.View.performClick(View.java:4240)
W/System.err(1777): at android.view.View$PerformClick.run(View.java:17721)
W/System.err(1777): at android.os.Handler.handleCallback(Handler.java:730)
W/System.err(1777): at android.os.Handler.dispatchMessage(Handler.java:92)
W/System.err(1777): at android.os.Looper.loop(Looper.java:137)
W/System.err(1777): at android.app.ActivityThread.main(ActivityThread.java:5103)
W/System.err(1777): at java.lang.reflect.Method.invokeNative(Native Method)
06-17 W / System.err（1777）：at java.lang.reflect.Method.invoke（Method.java:525）
W/System.err(1777): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
W/System.err(1777): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
我是初学者，任何帮助都将受到赞赏......
答案 0 :(得分：0)
在您使用的服务器中
socket.getOutputStream()
但它应该是
clientSocket.getOutputStream()