Question

我正在尝试使用套接字从VB.NET（服务器）向Android（客户端）发送一些命令。我可以将客户端连接到服务器，但我不知道如何接收服务器发送的命令。

以下是我的Android代码的一部分：

public void connect(View v){ //called on button click
    SERVER_IP = ip.getText().toString(); //it gets the server's ip from an editText
    SERVER_PORT = Integer.parseInt(port.getText().toString()); //and the port too
    Toast.makeText(this, "Trying to connect to\n" + SERVER_IP + ":" + SERVER_PORT + "...", Toast.LENGTH_SHORT).show();

    new Thread(new Runnable() {
        public void run() {
            InetAddress serverAddr;
            try {
                serverAddr = InetAddress.getByName(SERVER_IP);
                socket = new Socket(serverAddr, SERVER_PORT); //It establishes the connection with the server

                if(socket != null && socket.isConnected()){ //not sure if it is correct
                    BufferedReader input =  new BufferedReader(new InputStreamReader(socket.getInputStream()));

                    //Here comes the problem, I don't know what to add...

                }
            } catch (Exception e) {

            }
        }
    }).start();       
}

这是我的VB.NET发送代码的一部分：

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    send(TextBox1.text)
End Sub

Private Sub Send(ByVal command)
    Dim temp() As Byte = UTF8.GetBytes(command) 'Is UTF8 right to use for that?
    stream.Write(temp, 0, temp.Length)
    stream.Flush()
End Sub

问题1：我们是UTF8而不是ASCII编码吗？

问题2：如果Android代码想要使用每秒发送命令的计时器，我会在Android代码中更改什么？

感谢。

Answer 1

要从BufferedReader读取输入，您需要执行与此类似的操作：

BufferedReader input = new BufferedReader(new InputStreamReader(socket.getInputStream()));
String line;
while((line = input.readLine()) != null){
    // do something with the input here
}

有关套接字的精彩教程可从文档中的oracle获得：http://docs.oracle.com/javase/tutorial/networking/sockets/readingWriting.html

Android上的默认字符集是UTF-8 http://developer.android.com/reference/java/nio/charset/Charset.html，所以不用担心，但你总是可以从服务器向客户端发送一个字节流，然后根据需要对其进行解码。

要接收字节流，您需要执行此操作：

BufferedInputStream input = new BufferedInputStream(socket.getInputStream());
byte[] buffer = new byte[byteCount];
while(input.read(buffer, 0, byteCount) != -1 ){
     // do something with the bytes
     // for example decode it to string
     String decoded = new String(buffer, Charset.forName("UTF-8"));
     // keep in mind this string might not be a complete command it's just a decoded byteCount number of bytes
}

如您所见，如果发送字符串而不是字节，则会更容易。

如果你想定期从服务器接收输入，其中一个解决方案是创建一个循环，打开一个套接字，接收输入，处理它，关闭套接字，然后重复，我们你可以保持循环无休止地跑，直到某些命令，如＆＃34; STOP＆＃34;收到了。

如何读取VB.NET发送给Android的套接字命令？

1 个答案: