简而言之，我一直在使用简单的套接字和打印编写器制作 PC <---> Android 聊天。我有 PC 客户端和服务器工作，我不能去工作是 android 因为我真的很陌生。当我尝试连接时，任何人都可以帮我解决这个错误吗？
仅供参考：我确实在 google 和 asynctask 上的 stackoverflow 的其余部分上进行了查找，但没有什么是清楚的。我试图了解它是如何工作的，但没有一个例子接近。我更改了代码，因此我的 connectButton onClickListener 启动了一个新的 ServerTask（这是 AsyncTask），并将它放入我曾经在 onClickListener 上使用的代码中。我不得不注释掉异常，因为它正在写入 doInBackground 中的 UI，这显然是不可能的。我只是不明白为什么如果我启动了新的 AsyncTask 就无法连接
package com.example.JurkoAndroidChat;
import android.app.Activity;
import android.content.DialogInterface;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.view.View;
import java.net.*;
import java.io.*;
import java.util.*;
public class MyActivity extends Activity {
/**
* Called when the activity is first created.
*/
// Right here, we connecting the components of the main.xml form to code
Button connectButton, disconnectButton, sendButton;
TextView chatArea, clientArea;
EditText messageField, usernameField, ipField;
//Extra variables and sockets
String username, serverIP;
int Port = 5000;
Socket sock;
PrintWriter out;
BufferedReader in;
ArrayList<String> userList;
Boolean isConnected = false;
@Override
public void onCreate(Bundle savedInstanceState) {
System.out.println("Working?");
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
userList = new ArrayList();
connectButton = (Button)findViewById(R.id.button);
sendButton = (Button)findViewById(R.id.button1);
disconnectButton = (Button)findViewById(R.id.button2);
chatArea = (TextView)findViewById(R.id.textView2);
clientArea = (TextView)findViewById(R.id.textView3);
messageField = (EditText)findViewById(R.id.editText2);
usernameField = (EditText)findViewById(R.id.editText);
ipField = (EditText)findViewById(R.id.editText1);
connectButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//To change body of implemented methods use File | Settings | File Templates.
if (isConnected == false) {
username = usernameField.getText().toString();
usernameField.setFocusable(false);
usernameField.setClickable(false);
serverIP = ipField.getText().toString();
ipField.setFocusable(false);
ipField.setClickable(false);
executeTask();
} else if (isConnected == true) {
chatArea.append("You are already connected to the server.\n");
}
}
});
disconnectButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//To change body of implemented methods use File | Settings | File Templates.
String bye = (username + ": :Disconnect");
try {
out.print(bye);
out.flush();
chatArea.append("Disconnected.\n");
sock.close();
} catch (Exception e) {e.printStackTrace();}
isConnected = false;
usernameField.setFocusable(true);
usernameField.setClickable(true);
ipField.setFocusable(true);
ipField.setClickable(true);
clientArea.setText("");
}
});
sendButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//To change body of implemented methods use File | Settings | File Templates.
String nothing = "";
if ((messageField.getText().toString().equals(nothing))) {
messageField.setText("");
messageField.requestFocus();
} else {
try {
out.println(username + ":" + messageField.getText().toString() + ":" + "Chat");
out.flush();
} catch (Exception e) {
chatArea.append("Message was not sent.\n");
}
messageField.setText("");
messageField.requestFocus();
}
}
});
}
public class ServerTask extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... voids) {
try {
Log.i("Asynctask", "doInBackground");
sock = new Socket(serverIP, Port);
out = new PrintWriter(sock.getOutputStream());
in = new BufferedReader(new InputStreamReader(sock.getInputStream()));
out.println(username + ":" + "has connected." + ":" + "Connect");
out.flush();
isConnected = true;
} catch (Exception ex) {
// chatArea.append("Unable to connect to " + serverIP + " at port " + Port + "." + ex);
// ex.printStackTrace();
// usernameField.setFocusable(true);
// usernameField.setClickable(true);
// ipField.setFocusable(true);
// ipField.setClickable(true);
}
ListenThread();
return null; //To change body of implemented methods use File | Settings | File Templates.
}
@Override
protected void onPreExecute() {
super.onPreExecute();
//To change body of overridden methods use File | Settings | File Templates.
}
}
public void executeTask() {
new ServerTask().execute();
}
public class IncomingReader implements Runnable {
@Override
public void run() {
//To change body of implemented methods use File | Settings | File Templates.
String[] data;
String stream, done = "Done", connect = "Connect", disconnect = "Disconnect", chat = "Chat";
try {
while ((stream = in.readLine()) != null) {
data = stream.split(":");
if (data[2].equals(chat)) {
chatArea.append(data[0] + ": " + data[1] + '\n');
} else if (data[2].equals(connect)) {
chatArea.setText("");
userAdd(data[0]);
} else if (data[2].equals(disconnect)) {
userRemove(data[0]);
} else if (data[2].equals(done)) {
clientArea.setText("");
writeUsers();
userList.clear();
}
}
} catch (Exception e) {e.printStackTrace();}
}
}
public void ListenThread() {
Thread IncomingReader = new Thread(new IncomingReader());
IncomingReader.start();
}
public void userAdd(String data) {
userList.add(data);
}
public void userRemove(String data) {
chatArea.append(data + " has disconnected from the server.\n");
for (String token:userList)
if (token.equals(data))
userList.remove(token);
}
public void writeUsers() {
String[] tempList = new String[(userList.size())];
userList.toArray(tempList);
for (String token:tempList) {
clientArea.append(token + '\n');
}
}
}