我搜索了一些网站并了解到通过USB在Android设备（手机）和PC之间进行通信的方式是在手机上实现serversocket的应用程序和在PC上实现客户端套接字的另一个应用程序。我有点修复了手机端的应用程序（现在没有例外），但我得到一个异常“Ljava.lang.StackTraceElement”试图启动一个套接字（“localhost”，38300）。有谁知道这是怎么回事以及如何解决它？我附上了以下代码的两面。
我让它运行的步骤如下
：环境：
三星Android手机，Linux PC，Android Studio开发人员在Linux上运行
：连接步骤
注意：你们都可以看到我可以使用android studio“Android Monitor”窗口查看手机和PC的app shell的日志。
package com.example.seanhsu.androiddevice_serversocket;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketTimeoutException;
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 AndroidDevice_ServerSocket extends AppCompatActivity 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 String socketData = null;
private Handler mHandler = null;
ServerSocket server = null;
String msg;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_android_device__server_socket);
// Set up click listeners for the buttons
View connectButton = findViewById(R.id.connect_button);
connectButton.setOnClickListener(this);
View onBtn = findViewById(R.id.hdmi_on);
onBtn.setOnClickListener(this);
View offBtn = findViewById(R.id.hdmi_off);
offBtn.setOnClickListener(this);
// i = new Intent(this, Connected.class);
mHandler = new Handler();
}
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();
msg = "Attempting to connect...";
Log.e(TAG, "1 "+msg);
Toast.makeText(this, msg, Toast.LENGTH_SHORT/*msg.length()*/).show();
break;
case R.id.hdmi_on:
Log.e(TAG, "disconnect" + Globals.socketOut);
if (Globals.socketOut != null) {
Globals.socketOut.println("hdmiOn");
Globals.socketOut.flush();
msg = "disconnect hdmi on";
Log.e(TAG, "2 "+msg);
Toast.makeText(this, msg, Toast.LENGTH_SHORT/*msg.length()*/).show();
}
else
{
msg = "disconnect hdmi on is null";
Log.e(TAG, "3 "+msg);
Toast.makeText(this, msg, Toast.LENGTH_SHORT/*msg.length()*/).show();
}
break;
case R.id.hdmi_off:
Log.e(TAG, "disconnect" + Globals.socketOut);
if (Globals.socketOut != null) {
Globals.socketOut.println("hdmiOff!!");
Globals.socketOut.flush();
msg = "disconnect hdmi off";
Log.e(TAG, "4 "+msg);
Toast.makeText(this, msg, Toast.LENGTH_SHORT/*msg.length()*/).show();
}
else
{
msg = "disconnect hdmi off is null";
Log.e(TAG, "5 "+msg);
Toast.makeText(this, msg, Toast.LENGTH_SHORT/*msg.length()*/).show();
}
break;
}
}
private Runnable initializeConnection = new Thread() {
public void run() {
Socket client = null;
// initialize server socket
try {
server = new ServerSocket(38300);
server.setSoTimeout(TIMEOUT * 5000);
// attempt to accept a connection
client = server.accept();
Globals.socketIn = new Scanner(client.getInputStream());
Globals.socketOut = new PrintWriter(client.getOutputStream(),
true);
// Globals.socketIn.
} catch (SocketTimeoutException e) {
// print out TIMEOUT
Log.e(TAG, "aaa=== " + e);
msg = "Connection has timed out! Please try again";
Log.e(TAG, "6 "+msg);
//Toast.makeText(getBaseContext(), msg, Toast.LENGTH_SHORT).show();//method error, this causes program terminated
mHandler.post(showConnectionStatus);
} catch (IOException e) {
Log.e(TAG, "bbb=== " + e);
msg = "IO Exception";
Log.e(TAG, "7 "+msg);
//Toast.makeText(getBaseContext(), msg, Toast.LENGTH_SHORT).show();//method error, this causes program terminated
} finally {
// close the server socket
try {
if (server != null)
server.close();
} catch (IOException ec) {
Log.e(TAG, "ccc=== " + ec);
Log.e(TAG, "Cannot close server socket" + ec);
msg = "Cannot close server socket";
Log.e(TAG, "8 "+msg);
//Toast.makeText(getBaseContext(), msg, Toast.LENGTH_SHORT).show();//method error, this causes program terminated
}
}
if (client != null) {
Globals.connected = true;
// print out success
connectionStatus = "Connection was succesful!";
Log.e(TAG, "9 "+connectionStatus);
mHandler.post(showConnectionStatus);
while (Globals.socketIn.hasNext()) {
socketData = Globals.socketIn.next();
mHandler.post(socketStatus);
}
// startActivity(i);
}
}
};
/**
* Pops up a "toast" to indicate the connection status
*/
private Runnable showConnectionStatus = new Runnable() {
public void run() {
Log.e(TAG, "10 "+connectionStatus);
Toast.makeText(getBaseContext(), connectionStatus,
Toast.LENGTH_SHORT).show();
}
};
private Runnable socketStatus = new Runnable() {
public void run() {
TextView tv = (TextView) findViewById(R.id.connection_text);
tv.setText(socketData);
}
};
public static class Globals {
public static boolean connected;
public static Scanner socketIn;
public static PrintWriter socketOut;
}
}
package com.example.seanhsu.pchost_clientsocket_withactivity;
import android.support.v7.app.AppCompatActivity;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.PrintWriter;
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 PCHost_ClientSocket_with_Activity extends AppCompatActivity implements OnClickListener{
Socket socket;
PrintWriter out;
Scanner sc;
String msg;
private String TAG = "PCHost_ClientSocket_withActivity";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_pchost__client_socket_with_);
View connectButton = findViewById(R.id.connect_button);
connectButton.setOnClickListener(this);
//when the emulator start running, it's already in the emulator shell, so it cann't execute adb command
//execAdb();
}
public void onClick(View v) {
//cannot run on main thread
//need to run on another thread, otherwise it will get android.os.NetworkOnMainThreadException exception
new Thread(initializeConnection).start();
//initializeConnection();
/*while(sc.hasNext()) {
System.out.println(System.currentTimeMillis() + " / " + sc.nextLine());
Log.e(TAG, "12 "+System.currentTimeMillis() + " / " + sc.nextLine());
}*/
}
//cannot run on main thread
//need to run on another thread, otherwise it will get android.os.NetworkOnMainThreadException exception
private Runnable initializeConnection = new Thread() {
public void run() {
msg = "initializeConnection";
Log.e(TAG, msg);
//Create socket connection
try{
Log.e(TAG, "============0============");
socket = new Socket("localhost", 38300);
Log.e(TAG, "============1============");
out = new PrintWriter(socket.getOutputStream(), true);
Log.e(TAG, "============2============");
//in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
sc=new Scanner(socket.getInputStream());
Log.e(TAG, "============3============");
// add a shutdown hook to close the socket if system crashes or exists unexpectedly
Thread closeSocketOnShutdown = new Thread() {
public void run() {
try {
Log.e(TAG, "============4============");
socket.close();
msg = "closeSocketOnShutdown socket close";
Log.e(TAG, msg);
Toast.makeText(getBaseContext(), msg, Toast.LENGTH_SHORT).show();
} catch (IOException e) {
Log.e(TAG, "============5============");
e.printStackTrace();
msg = "closeSocketOnShutdown IOException";
Log.e(TAG, msg);
Toast.makeText(getBaseContext(), msg, Toast.LENGTH_SHORT).show();
}
}
};
Log.e(TAG, "============6============");
Runtime.getRuntime().addShutdownHook(closeSocketOnShutdown);
Log.e(TAG, "============7============");
} catch (UnknownHostException e) {
//Print.fatalError(“Socket connection problem (Unknown host)”+e.getStackTrace());
msg = "Socket connection problem (Unknown host)"+e.getStackTrace();
Log.e(TAG, msg);
Toast.makeText(getBaseContext(), msg, Toast.LENGTH_SHORT).show();
} catch (IOException e) {
//Print.fatalError(“Could not initialize I/O on socket “+e.getStackTrace());
msg = "Could not initialize I/O on socket "+e.getStackTrace();
Log.e(TAG, msg);
Toast.makeText(getBaseContext(), msg, Toast.LENGTH_SHORT).show();
}
}
};
}
我一直异常：
无法初始化套接字上的I / O [Ljava.lang.StackTraceElement; @ 14710f5
最初我在手机端应用程序上也有IO异常，但我在清单中添加了<uses-permission android:name="android.permission.INTERNET"/>，现在没关系。因此，我还在PC端应用程序的清单中添加<uses-permission android:name="android.permission.INTERNET"/>，但仍无法解决此问题。