java - 将 float 据发送到我的客户端应用程序

Question

我用 C 语言编写了一段服务器代码，我希望每次迭代都将数据连续发送到我的客户端应用程序。

while (1)
{
    startInt = mymillis();//capture starting time

    Sensor_raw_data_float = Sensor_Read_Values_();
    float data = Sensor_raw_data_float.x * 0.007;

    send(sockfd, &data , sizeof(float),0);//Send to client

    //Wait until 5ms
    while (mymillis() - startInt < (5))
    {
        usleep(100);
    }

}

我尝试在发送之前使用“snprintf”将 float 据转换为字符串，但我意识到整个系统开始变慢并且滞后很多。

因此，我尝试对客户端代码进行编辑。附件是我的客户端代码的主要部分，与我想要做的事情相关

    import android.os.Bundle;
    import android.os.Handler;
    import android.os.Message;
    import android.support.v7.app.AppCompatActivity;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

EditText editTextAddress, editTextPort, editTextMsg;
Button buttonConnect, buttonDisconnect, buttonSend;
TextView textViewState, textViewRx;

ClientHandler clientHandler;
ClientThread clientThread;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

textViewRx = (TextView) findViewById(R.id.received);

    clientHandler = new ClientHandler(this);
}

private void updateState(String state){
    textViewState.setText(state);
}

private void updateRxMsg(String rxmsg){
    textViewRx.append(rxmsg + "\n");

}


public static class ClientHandler extends Handler {
    public static final int UPDATE_STATE = 0;
    public static final int UPDATE_MSG = 1;
    public static final int UPDATE_END = 2;
    private MainActivity parent;

    public ClientHandler(MainActivity parent) {
        super();
        this.parent = parent;
    }

    @Override
    public void handleMessage(Message msg) {

        switch (msg.what){
            case UPDATE_STATE:
                parent.updateState((String)msg.obj);
                break;
            case UPDATE_MSG:
                parent.updateRxMsg((String)msg.obj);
                break;
            case UPDATE_END:
                parent.clientEnd();
                break;
            default:
                super.handleMessage(msg);
        }

    }

}

}

我尝试将 updateRxMsg(String rxmsg) 的代码编辑为

 private void updateRxMsg(String rxmsg){
    private void updateRxMsg(String rxmsg){
    //textViewRx.append(rxmsg + "\n");
    float f = Float.parseFloat(rxmsg);
    String mytext=Float.toString(f);
    textViewRx.append(mytext + "\n");
}

}

但我的 TextView 上仍然打印出垃圾。我无法弄清楚问题是什么，但我怀疑它与编码有关。我想获得一些有关如何将 float 数据从服务器传输到客户端的帮助。

更新:附件是我的缓冲区读取器等的代码......，最初我认为问题不在这里，但我也会将其发布在这里。

public class ClientThread extends Thread{

String dstAddress;
int dstPort;
private boolean running;
MainActivity.ClientHandler handler;

Socket socket;
PrintWriter printWriter=null;
BufferedReader bufferedReader;

public ClientThread(String addr, int port, MainActivity.ClientHandler handler) {
    super();
    dstAddress = addr;
    dstPort = port;
    this.handler = handler;
    StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
            .permitAll().build();
    StrictMode.setThreadPolicy(policy);
}

public void setRunning(boolean running){
    this.running = running;
}

private void sendState(String state){
    handler.sendMessage(
            Message.obtain(handler,
                    MainActivity.ClientHandler.UPDATE_STATE, state));
}

public void txMsg(String msgToSend){
    if(printWriter != null){
        printWriter.println(msgToSend);
    }
}

@Override
public void run() {
    sendState("connecting...");

    running = true;

    try {
        socket = new Socket(dstAddress, dstPort);
        sendState("connected");

        OutputStream outputStream = socket.getOutputStream();
        printWriter = new PrintWriter(outputStream, true);

        InputStream inputStream = socket.getInputStream();
        InputStreamReader inputStreamReader =
                new InputStreamReader(inputStream);
        bufferedReader = new BufferedReader(inputStreamReader);

        while(running){

            //bufferedReader block the code
            String line = bufferedReader.readLine();
            if(line != null){
                handler.sendMessage(
                        Message.obtain(handler,
                                MainActivity.ClientHandler.UPDATE_MSG, line));
            }

        }

    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if(bufferedReader != null){
            try {
                bufferedReader.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        if(printWriter != null){
            printWriter.close();
        }

        if(socket != null){
            try {
                socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    handler.sendEmptyMessage(MainActivity.ClientHandler.UPDATE_END);
}

}

我将代码更新为:

import android.os.Message;
import android.os.StrictMode;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;
import java.nio.ByteBuffer;

公共(public)类 ClientThread 扩展 Thread{

String dstAddress;
int dstPort;
private boolean running;
MainActivity.ClientHandler handler;

Socket socket;
PrintWriter printWriter=null;
BufferedReader bufferedReader;

public ClientThread(String addr, int port, MainActivity.ClientHandler handler) {
    super();
    dstAddress = addr;
    dstPort = port;
    this.handler = handler;
    StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
            .permitAll().build();
    StrictMode.setThreadPolicy(policy);
}

public void setRunning(boolean running){
    this.running = running;
}

private void sendState(String state){
    handler.sendMessage(
            Message.obtain(handler,
                    MainActivity.ClientHandler.UPDATE_STATE, state));
}

public void txMsg(String msgToSend){
    if(printWriter != null){
        printWriter.println(msgToSend);
    }
}

@Override
public void run() {
    sendState("connecting...");

    running = true;

    try {
        socket = new Socket(dstAddress, dstPort);
        sendState("connected");

        OutputStream outputStream = socket.getOutputStream();
        printWriter = new PrintWriter(outputStream, true);

        InputStream inputStream = socket.getInputStream();
        InputStreamReader inputStreamReader =
                new InputStreamReader(inputStream);
        bufferedReader = new BufferedReader(inputStreamReader);

        int bufferSize = 8192;

        ByteBuffer bf = ByteBuffer.allocate(bufferSize);
            BufferedInputStream inFromServer = new BufferedInputStream(socket.getInputStream());
            while (true) {
                int b = inFromServer.read();
                if (b == -1) {
                    break;
                }
                bf.put( (byte) b);

                handler.sendMessage(
                        Message.obtain(handler,
                                MainActivity.ClientHandler.UPDATE_MSG, (byte) b));
            }

       // while(running){

            //bufferedReader block the code
        //    String line = bufferedReader.readLine();
       //     if(line != null){
       //         handler.sendMessage(
       //                 Message.obtain(handler,
       //                         MainActivity.ClientHandler.UPDATE_MSG, line));
      //      }

      //  }

    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if(bufferedReader != null){
            try {
                bufferedReader.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        if(printWriter != null){
            printWriter.close();
        }

        if(socket != null){
            try {
                socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    handler.sendEmptyMessage(MainActivity.ClientHandler.UPDATE_END);
}

}

我很困惑应该更改什么才能使字节缓冲区正常工作，并且不确定我是否正确更改了它。 谢谢!

Answer 1

下定决心。

如果您直接发送 float，请根据您发布的代码，使用 DataInputStream.readFloat() 读取它。如果幸运的话并且字节序是相同的，那么就完成了。

或者将其转换为字符串，将其作为一行发送，将其作为一行读取，然后将其解析回float。

不是两者的混合。