小编chr*_*uch的帖子

好吧,我正在尝试创建一个与我已经设置,测试过的套接字通信的应用程序,并在一个简单的Java应用程序的后台工作.

问题是,我的应用程序立即强制关闭.在fcs之前你没有机会看到任何东西.

这是我的代码:

import java.io.IOException;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Scanner;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.EditText;
import android.widget.Toast;

public class LogMeInClientActivity extends Activity {
    private Socket s;
    private InetAddress hostIp, localIp;
    private final String hostName = "localhost";
    private final int port = 4000;
    private Scanner in;
    private PrintWriter out;
    private final EditText usernameField = (EditText)     findViewById(R.id.username_field),
            passwordField = (EditText) findViewById(R.id.password_field);
    private String username, password;

    @Override
    public void onCreate(Bundle savedInstanceState) …