return new BufferedReader(new InputStreamReader(socketIn));的作用

A：这行代码的作用是创建一个输入流读取器(BufferedReader)，用于读取套接字(Socket)的输入流(socketIn)中的数据。具体步骤是：先使用InputStreamReader将字节流转换为字符流，再将字符流封装成BufferedReader，以便于逐行读取文本数据。最终返回的是一个BufferedReader对象，可以使用它的readLine()方法读取套接字输入流中的一行文本数据。

相关问题

protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); ipEditText = findViewById(R.id.ipEditText); portEditText = findViewById(R.id.portEditText); Button connectButton = findViewById(R.id.connectButton); connectButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { String ip = ipEditText.getText().toString(); int port = Integer.parseInt(portEditText.getText().toString()); new ConnectTask().execute(ip, String.valueOf(port)); } }); Button sendMessageButton = findViewById(R.id.sendMessageButton); sendMessageButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { showSendMessageDialog(); } }); } private class ConnectTask extends AsyncTask<String, Void, Void> { @Override protected Void doInBackground(String... params) { String ip = params[0]; int port = Integer.parseInt(params[1]); try { socket = new Socket(ip, port); in = new BufferedReader(new InputStreamReader(socket.getInputStream())); out = new PrintWriter(socket.getOutputStream(), true); } catch (UnknownHostException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return null; }加入一个滑块能向所连端口发送不同位置对应的数字

你可以在布局文件中添加一个SeekBar，然后在Java代码中获取其值并发送给所连接的端口。具体实现可以按照以下步骤进行：

1. 在布局文件中添加SeekBar组件：

<SeekBar
    android:id="@+id/seekBar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:max="100"
    android:progress="0" />

2. 在onCreate方法中获取SeekBar组件并为其设置监听器：

SeekBar seekBar = findViewById(R.id.seekBar);
seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
    @Override
    public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
        // 发送SeekBar的当前值给所连接的端口
        out.println(progress);
    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {}

    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {}
});

3. 在ConnectTask类中，将out对象定义为成员变量，以便在SeekBar的监听器中使用：

private class ConnectTask extends AsyncTask<String, Void, Void> {
    private PrintWriter out;

    @Override
    protected Void doInBackground(String... params) {
        String ip = params[0];
        int port = Integer.parseInt(params[1]);
        try {
            socket = new Socket(ip, port);
            in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            out = new PrintWriter(socket.getOutputStream(), true);
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
}

import java.net. *; import java.io. *; public class EchoClient{ public static void main(String args[]){ try{ Socket connection = new Socket(args[0], 7); System.out.println("Connection established:"); DataInputStream in = new DataInputStream( connection.getInputStream()); DataOutputStream out = new DataOutputStream( connection.getoutputStream()); String line = new String(""); while(!line.toUpperCase().equals(".QUIT")){ System.out.print("Enter string: "); line = readString(); System.out.println("\tSending string to server... "); out.writeUTF(line); System.out.println("\tWaiting for server response... "); line = in.readUTF(); System.out.println("Received: " + line);} in.close(); out.close(); connection.close(); } catch(UnknownHostException uhe){ System.err.println("Unknon host: " + args[0]); } catch(IOException ioe) { System.err.println("IOException: " + ioe); } } public static String readString(){ String string = new String(); BufferedReader in = new BufferedReader(new InputStreamReader(System.in)); try{ string = in.readLine(); }catch(IOException e){ System. out. println("Console. readString: Unknon error..."); System.exit(-1); } return string;} }哪里错了

代码有一个小写字母错误，它导致了编译错误。第16行中的 `connection.getoutputStream()` 应该改为 `connection.getOutputStream()`。将该行代码更改为以下代码将解决问题：

DataOutputStream out = new DataOutputStream(connection.getOutputStream());

除此之外，还有一些其他的小问题：

1. 在 `String` 对象初始化时，最好使用 `""` 而不是 `new String()`。
2. 在 `catch` 语句中，应该使用 `System.out.println()` 而不是 `System. out. println()`。
3. 在 `readString()` 方法中，有一个拼写错误，应该是 "unknown" 而不是 "unknon"。
4. 最后，建议在 `catch` 块中输出详细的错误信息，以便更好地调试问题。

修改后的代码如下所示：

import java.net.*;
import java.io.*;

public class EchoClient {
    public static void main(String args[]) {
        try {
            Socket connection = new Socket(args[0], 7);
            System.out.println("Connection established:");
            DataInputStream in = new DataInputStream(connection.getInputStream());
            DataOutputStream out = new DataOutputStream(connection.getOutputStream());
            String line = "";
            while (!line.toUpperCase().equals(".QUIT")) {
                System.out.print("Enter string: ");
                line = readString();
                System.out.println("\tSending string to server... ");
                out.writeUTF(line);
                System.out.println("\tWaiting for server response... ");
                line = in.readUTF();
                System.out.println("Received: " + line);
            }
            in.close();
            out.close();
            connection.close();
        } catch (UnknownHostException uhe) {
            System.err.println("Unknown host: " + args[0]);
        } catch (IOException ioe) {
            System.err.println("IOException: " + ioe.getMessage());
        }
    }

    public static String readString() {
        String string = "";
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        try {
            string = in.readLine();
        } catch (IOException e) {
            System.err.println("Console.readString: Unknown error...");
            System.exit(-1);
        }
        return string;
    }
}

希望这可以帮助您解决问题！