与USB连接

Question

我想在设备连接到pc时显示消息。我的代码如下所示。但是发生了一些异常。在debuging之后，它从处理程序切换到catch块而不是在try块中。任何人都可以告诉我为什么会发生这种情况。 感谢。

package com.ex;


import java.io.IOException;
import java.io.PrintWriter;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketTimeoutException;
import java.net.UnknownHostException;
import java.util.Scanner;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.TextView;
import android.widget.Toast;


public class Connection extends Activity implements OnClickListener {

    public static final String TAG="Connection";
    public static final int TIMEOUT=10;
    Intent i=null;
    TextView tv=null;
    private String connectionStatus=null;
    private Handler mHandler=null;
    ServerSocket server=null;
    Handler mHandler1=null;
    Scanner socketIn; 
    PrintWriter socketOut;
    boolean connected; 

    @Override
    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


    //Set up click listeners for the buttons
    View connectButton = findViewById(R.id.connect_button);
    connectButton.setOnClickListener(this);

    i = new Intent(this, Connected.class);
    mHandler=new Handler();
    }




    @Override
    public void onClick(View v) {
    switch (v.getId()) {
    case R.id.connect_button:
    tv = (TextView) findViewById(R.id.connection_text);
    //initialize server socket in a new separate thread
    new Thread(initializeConnection).start();
    String msg="Attempting to connect...";
    Toast.makeText(Connection.this, msg, msg.length()).show();
    break;
    }
    }

    private Runnable initializeConnection = new Thread() {
    public void run() {

    Socket client = null;
    try {
        client = new Socket("192.168.18.116", 8080);
    } catch (UnknownHostException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    } catch (IOException e1) {                                     
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }
    // initialize server socket
    try{
    server = new ServerSocket();
    server.setReuseAddress(true);
    server.setSoTimeout(TIMEOUT*1000);
    server.bind(new InetSocketAddress(5037));

    while((client = server.accept()) == null);


    //attempt to ccept a connection
    client = server.accept();
    socketIn=new Scanner(client.getInputStream());
    socketOut = new PrintWriter(client.getOutputStream(), true);
    } catch (SocketTimeoutException e) {
    // print out TIMEOUT
    connectionStatus="Connection has timed out! Please try again";
    System.out.println("++++++++++++++++nistha+++++++++++++"+connectionStatus);
    mHandler.post(showConnectionStatus);
    System.out.println("++++++++++++++++nistha+++++++++++++"+mHandler.post(showConnectionStatus));
    } catch (IOException e) {
    Log.e(TAG, ""+e);
    } finally {
    //close the server socket
    try {
    if (server!=null)
    server.close();

    } catch (IOException ec) {
    Log.e(TAG, "Cannot close server socket"+ec);
    System.out.println("#########Nis#########"+Log.e(TAG, "Cannot close server socket"+ec));
    }
    }

    if (client!=null) {
    connected=true;


    // print out success

    connectionStatus="Connection was succesful!";
    mHandler.post(showConnectionStatus);
    System.out.println("#########Nis#########"+mHandler.post(showConnectionStatus));
    startActivity(i);
    }
    }
    };

    /**
    * Pops up a "toast" to indicate the connection status
    */
    private Runnable showConnectionStatus = new Runnable() {
    public void run() {
    Toast.makeText(Connection.this, connectionStatus, Toast.LENGTH_SHORT).show();
    }
    };
/*
*//**
* Initialize connection to the phone
*
*/
    /*

public void initializeConnection(){
//Create socket connection
try{
final Socket socket = new Socket("localhost", 38300);
PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
//in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
Scanner sc = new Scanner(socket.getInputStream());
System.out.println("########Nistha##########"+sc);
// add a shutdown hook to close the socket if system crashes or exists unexpectedly
Thread closeSocketOnShutdown = new Thread() {
public void run() {
try {
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
};
Runtime.getRuntime().addShutdownHook(closeSocketOnShutdown);
} catch (UnknownHostException e) {
Print.fatalError("Socket connection problem (Unknown host)"+e.getStackTrace());
} catch (IOException e) {
Print.fatalError("Could not initialize I/O on socket "+e.getStackTrace());
}
*/

}