Android Socket例子

布局文件activity_socket.xml：

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".SocketActivity">

    <ImageView
        android:id="@+id/socket_actionBar_bg"
        android:layout_width="match_parent"
        android:layout_height="64dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        android:background="@color/colorModel"/>

    <ImageView
        android:id="@+id/socket_back_bt"
        android:layout_width="25dp"
        android:layout_height="25dp"
        app:layout_constraintBottom_toBottomOf="@+id/socket_actionBar_bg"
        app:layout_constraintLeft_toLeftOf="@+id/socket_actionBar_bg"
        android:layout_marginLeft="5dp"
        android:layout_marginBottom="7dp"
        android:padding="3dp"
        android:src="@mipmap/back"
        android:onClick="socket_backClick"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintLeft_toLeftOf="@+id/socket_actionBar_bg"
        app:layout_constraintBottom_toBottomOf="@+id/socket_actionBar_bg"
        app:layout_constraintRight_toRightOf="@+id/socket_actionBar_bg"
        android:layout_marginBottom="5dp"
        android:text="@string/SocketActivity_title"
        android:textColor="@color/colorWhite"
        android:textSize="12pt"/>

    <Button
        android:id="@+id/socket_send_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintTop_toBottomOf="@+id/socket_actionBar_bg"
        app:layout_constraintRight_toRightOf="@+id/socket_actionBar_bg"
        android:layout_marginTop="20dp"
        android:layout_marginRight="20dp"
        android:text="Send"
        android:textColor="@color/colorWhite"
        android:background="@color/colorSelect"
        android:onClick="socket_SendMessage"/>


    <EditText
        android:id="@+id/socket_command"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintTop_toTopOf="@+id/socket_send_button"
        app:layout_constraintRight_toLeftOf="@+id/socket_send_button"
        app:layout_constraintLeft_toLeftOf="parent"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"/>

    <TextView
        android:id="@+id/socket_content"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintTop_toBottomOf="@+id/socket_command"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        android:layout_margin="20dp"
        android:background="@color/colorBlack"
        android:textColor="@color/colorWhite"
        android:scrollbars="vertical"/>


</androidx.constraintlayout.widget.ConstraintLayout>

SocketActivity.java：

import android.content.Context;
import android.os.Bundle;
import android.os.Message;
import android.text.method.ScrollingMovementMethod;
import android.util.Log;
import android.view.Gravity;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class SocketActivity extends AppCompatActivity implements MyHandler.InMyHandler{

    //主线程Handler,用于将从服务器获取的消息显示出来
    private MyHandler myHandler;
    //采用线程池进行线程管理
    private ExecutorService mThreadPool;
    //Socket变量
    private Socket socket;
    //输出流
    private OutputStream outputStream;
    //服务器返回的数据转化为StringBuffer
    private StringBuffer responseBuffer;

    //UI控件
    private EditText editText;
    private TextView textView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_socket);
        //控件
        editText = findViewById(R.id.socket_command);
        textView = findViewById(R.id.socket_content);
        textView.setMovementMethod(ScrollingMovementMethod.getInstance());

        //初始化线程池
        mThreadPool = Executors.newCachedThreadPool();
        //获取处理消息的Handler单例
        myHandler = MyHandler.getInstance();
        //设置接口监听
        myHandler.setInMyHandler(this);
        //开启socket线程
        socket_thread();

    }

    /**
     *开启socket线程，连接，获取输入输出流
     */
    private void socket_thread(){
        //利用线程池开启一个线程并执行该线程
        mThreadPool.execute(new Runnable() {
            @Override
            public void run() {
                try {
                    //创建Socket
                    socket = new Socket("192.168.0.xxx",1000);
                    //判断客户端和服务器是否连接成功
                    if (socket.isConnected()){
                        //连接成功,message.what=1
                        myHandler.sendEmptyMessage(1);

                        //获取socket的输出流
                        outputStream = socket.getOutputStream();

                        //输入流,读取服务器返回的数据
                        InputStream inputStream = socket.getInputStream();
                        //创建一个字节数组用来接收服务端发来的字节流，多大自己说了算
                        byte[] b = new byte[1024];
                        //写一个死循环，不停的接收服务端发来的数据
                        while (socket.isConnected()) {
                            //将数据读入字节数组，返回长度
                            int length = inputStream.read(b);
                            //如果服务端没发数据就return不在往下执行，继续读数据
                            if (length <= 0) return;
                            //如果服务端发的数据不为空，则把字节数组转成字符串
//                            String str = new String(b, 0, length, "gb2312");
                            String str = new String(b, 0, length);
                            responseBuffer = new StringBuffer(str);
                            myHandler.sendEmptyMessage(2);
                        }

                    }else {
                        //连接失败,message.what=0
                        myHandler.sendEmptyMessage(0);
                    }

                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     *socket发送数据
     */
    private void socketSendMessage(String str){
        //利用线程池开启一个线程并执行该线程
        mThreadPool.execute(new Runnable() {
            @Override
            public void run() {
                try {
                    //首先判断一下socket是不是已经创建连接了，如果没有就不管它
                    if (socket == null) return;
                    if (outputStream == null) return;
                    outputStream.write(str.getBytes());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     *连接结果
     */
    private void handlerConnectResult(int result){
        if (result==0){
            Toast.makeText(this,"Connect Failed",Toast.LENGTH_SHORT).show();
        }else {
            Toast.makeText(this,"Connect Success",Toast.LENGTH_SHORT).show();
        }
    }

    /**
     *socket接收数据
     */
    private void handlerDataFeedBack(){
        StringBuffer stringBuffer = new StringBuffer(textView.getText().toString());
        stringBuffer.append(responseBuffer);
        textView.setText(stringBuffer);
        textView.setGravity(Gravity.BOTTOM);
    }

    /**
     *更新UI
     */
    @Override
    public void InHandleMessage(Message message) {
        switch (message.what) {
            case 0:
                handlerConnectResult(0);
                break;
            case 1:
                handlerConnectResult(1);
                break;
            case 2:
                handlerDataFeedBack();
                break;
        }
    }

    /**
     *发送按钮点击事件处理
     */
    public void socket_SendMessage(View view){
        String str = editText.getText().toString();
        editText.setText("");
        InputMethodManager im = (InputMethodManager) this.getSystemService(Context.INPUT_METHOD_SERVICE);
        im.hideSoftInputFromWindow(this.getWindow().getDecorView().getWindowToken(),0);
        //判断传入字符串为空则不作处理
        if (str.length()<=0) return;
        //发送socket数据
        socketSendMessage(str);
    }

    public void socket_backClick(View view){
        finish();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        //视图销毁时断开socket连接
        try {
            outputStream = null;//关闭输出流
            socket.close();//关闭socket
            socket = null;
        } catch (IOException e) {
            e.printStackTrace();
        }
        mThreadPool = null;//销毁线程池
        myHandler.removeInMyHandler();//移除接口监听
        myHandler = null;
        responseBuffer = null;
    }

}

MyHandler.java：

import android.os.Handler;
import android.os.Message;

/**
 * Handler单例的封装
 */
public class MyHandler extends Handler {
    private MyHandler(){}
    private static class MyHandlerHolder{
        private static final MyHandler INSTANCE = new MyHandler();
    }
    static MyHandler getInstance(){
        return MyHandlerHolder.INSTANCE;
    }//返回线程安全的单例

    @Override
    public void handleMessage(Message message){//重写handleMessage方法
        super.handleMessage(message);
        if (inMyHandler!=null){
            inMyHandler.InHandleMessage(message);//调用接口方法
        }
    }

    private static InMyHandler inMyHandler;//定义接口变量
    public interface InMyHandler{//定义接口
        void InHandleMessage(Message message);//定义接口方法
    }
    void setInMyHandler(InMyHandler inMyHandler){//注册接口的方法
        MyHandler.inMyHandler = inMyHandler;//接口的引用指向它的实例化对象,传入的参数inMyHandler为实现该接口的类的实例化对象
    }
    void removeInMyHandler(){//取消注册接口的方法
        MyHandler.inMyHandler = null;//inMyHandler置为null，inMyHandler将不再持有外部类引用
    }

}