我正试图进入物联网，并想让一个应用程序从Android手机发送一个字符串到Linux电脑。该应用程序通过实现asynctask执行此操作：
//From the java docs, slightly modified
private Void sendThroughSocket(String s, String host, int port) {
Log.d("E", "In send through socket");
final String hostName = host;//Host is the address of the receiver, can be IP or domain
int portNumber = port;
//Check if device is connected to internet
try {
Socket clientsocket = new Socket(hostName, portNumber); //one of 2-way point communication
Log.d("E", "Created Socket: ");
DataOutputStream DOS = new DataOutputStream(clientsocket.getOutputStream());
if (clientsocket.isConnected())
Log.d("E", "Socket connected");
DOS.writeUTF(s);
clientsocket.close();
} catch (UnknownHostException e) {
System.err.println("Don't know about host " + hostName);
new Runnable() {
public void run() {
Toast.makeText(context, "Don't know about host " + hostName, Toast.LENGTH_SHORT).show();
}
};
} catch (IOException e) {
System.err.println("Couldn't get I/O for the connection to " + hostName);
//Toast can not be run using asynctask since it acesses UI
new Runnable() {
public void run() {
Toast.makeText(context, "Couldn't get I/O for the connection to " + hostName + " , check the port", Toast.LENGTH_SHORT).show();
}
};
} catch (Exception e) {
Log.d("E", "#fares" + e.getClass().getName().toString());
}
return null;
}
我有3次尝试发送字符串，全部是从我的搜索栏触发的（我将搜索栏进度值作为我的字符串发送）： public void onProgressChanged（SeekBar seekBar，int i，boolean b） public void onStartTrackingTouch（SeekBar seekBar） public void onStopTrackingTouch（SeekBar seekBar）
所有3的实现都是一样的： public void onProgressChanged（SeekBar seekBar，int i，boolean b）{
progressvalue = i;
textView.setText("Brightness = " + progressvalue + " %");
if (((RecieverPort.equals("Please enter port Number")) || (RecieverIP.equals("Please enter receiver IP")))) {
//Make sure toast isn't persistent
if (IPPortToastcount++ == 0)
Toast.makeText(MainActivity.this, "Please set both IP and Port ", Toast.LENGTH_SHORT).show();
} else {
//Check if connected to internet
if (!isConnectedtoInternet(MainActivity.this)) {
if (ConnectivityToastCount++ < 1)
Toast.makeText(MainActivity.this, "You are not connected to the Internet", Toast.LENGTH_SHORT).show();
} else {
//Send text over wifi
SendText ST = new SendText(getApplicationContext());
ST.execute(String.valueOf(progressvalue), RecieverIP, RecieverPort);
ST.cancel(false);
}
}
}
主要
//Send text over wifi
SendText ST = new SendText(getApplicationContext());
ST.execute(String.valueOf(progressvalue), RecieverIP, RecieverPort);
ST.cancel(false);
服务器端（我的电脑）非常简单：
int portNumber = 44339; // Choose unused port on router
//Open a socket
try {
//System.out.println("in try statement");
try (ServerSocket serverSocket1 = new ServerSocket(portNumber)) {
portNumber = serverSocket1.getLocalPort();
System.out.println("Created socket at port " + portNumber);
Socket clientSocket = serverSocket1.accept();
System.out.println("Accepted");
DataInputStream DIS = new DataInputStream(clientSocket.getInputStream()); //get input from socket
//System.out.println("Created reader");
String inputLine;
// System.out.println("About to read");
while (DIS.available() > 0) {
inputLine = DIS.readUTF();
System.out.println(inputLine);
}
}
} catch (Exception e) {
System.out.println("Exception caught when trying to listen on port "
+ portNumber + " or listening for a connection");
System.out.println(e.getClass().getSimpleName());
}
这种工作，除了在接受服务器套接字之前需要很长时间（秒）。它也只适用于onprogresschanged，这让我相信多次尝试
//Send text over wifi
SendText ST = new SendText(getApplicationContext());
ST.execute(String.valueOf(progressvalue), RecieverIP, RecieverPort);
ST.cancel(false);
。如何确保一次点击或该函数的一次调用足以发送字符串？ 对不起，很长的帖子，但这是我第一次问：）
编辑：我的新服务器代码：
try {
//System.out.println("in try statement");
try ( ServerSocket serverSocket1 = new ServerSocket(portNumber))
{
portNumber = serverSocket1.getLocalPort();
System.out.println("Created socket at port " + portNumber);
while(true){
Socket clientSocket = serverSocket1.accept();
// System.out.println("Accepted");
DataInputStream DIS = new DataInputStream(clientSocket.getInputStream()); //get input from socket
//System.out.println("Created reader");
//String inputLine;
//System.out.println("About to read");
System.out.println(DIS.readUTF());
}
}
} catch (Exception e) {
System.out.println("Exception caught when trying to listen on port "
+ portNumber + " or listening for a connection");
System.out.println(e.getClass().getSimpleName());
}
值得注意的是，即使在while循环中，服务器也会始终显示4个数字然后停止。
编辑：这是一个示例日志： 10-06 20：08：09.145 26372-26372 / com.example.fares.ledslider D / E：测试方法中的#fares值= 50 10-06 20：08：26.475 26372-26372 / com.example.fares.ledslider D / E：#Fares in start tracking 10-06 20：08：26.722 26372-27004 / com.example.fares.ledslider D / E：#fares连接套接字 10-06 20：08：26.810 26372-26764 / com.example.fares.ledslider D / E：#fares连接套接字 10-06 20：08：27.241 26372-27003 / com.example.fares.ledslider D / E：#fares连接套接字 10-06 20：08：27.304 26372-26372 / com.example.fares.ledslider D / E：停止跟踪中的#fares
答案 0 :(得分：0)
可以删除ST.cancel（）。也不等待可用性看起来不太好。