15.Android-實現TCP客戶端,支持讀寫

在上章14.Android-使用sendMessage線程之間通信我們學習瞭如何線上程之間發送數據.

接下來我們便來學習如何通過socket讀寫TCP.

需要註意的是socket必須寫在子線程中,不能在ui主線程中直接使用,所以我們這裡創建了兩個class:

MainActivity(主界面)、TcpThread(獲取socket接收的數據)

由於代碼有註釋了,所以就不解釋了.

1.gif效果如下

2.activity_main.xml如下所示:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    
    <EditText 
        android:id="@+id/et_text"
        android:layout_width="match_parent"
           android:layout_height="wrap_content"
           android:layout_alignParentTop="true"
        android:hint="請填入要發送的內容"
        />
    
     <Button 
        android:id="@+id/btn_send"
        android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           android:layout_alignParentRight="true"
           android:layout_below="@+id/et_text"
        android:text="發送"
        />
     
     <TextView 
         android:id="@+id/tv_recv"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:layout_below="@+id/btn_send"
         android:minLines="20"
         android:hint="接收的內容"
         />
</RelativeLayout>

3.MainActivity.java如下所示

package com.example.tcpdemo;


import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

    TcpThread mt;
    
    TextView tv_recv;
    EditText et_text;        //要發送的內容
    Button    btn_send;
    
    //定義一個handler
    public Handler mHandler = new Handler() {
        public void handleMessage(Message msg) {
            //列印伺服器端發來的消息
            System.out.println("read:"+msg.obj.toString());
            tv_recv.append(msg.obj.toString()+"\r\n");
        };
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        tv_recv =  (TextView)findViewById(R.id.tv_recv);
        et_text =  (EditText)findViewById(R.id.et_text);
        
        
        mt = new TcpThread();
        mt.setHandler(mHandler);    //設置handler
        mt.setIp("10.10.10.104");   //設置伺服器地址
        mt.start();                    //啟動線程
        
        
        btn_send =  (Button)findViewById(R.id.btn_send);
        
        btn_send.setOnClickListener(new OnClickListener() {
            
            //向伺服器端發送數據
            public void onClick(View v) {
                
                if(!mt.write(et_text.getText().toString()))
                {
                    Toast.makeText(getApplicationContext(), "發送失敗", Toast.LENGTH_SHORT).show();
                    
                }
            }
        });
    }
}

4.TcpThread.java如下所示

package com.example.tcpdemo;


import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.net.UnknownHostException;

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

public class TcpThread extends Thread {
    
        
        Handler mHandler=null; 
        Socket socket = null;
        String ip = null;
        OutputStream outputStream = null;        //輸出流
        InputStream inputStream=null;            //接收流
        //獲取另一個線程的Handler
        public void setHandler( Handler handler){
            mHandler = handler;
        }
        
        //設置伺服器IP
        public void setIp(String ip){
            this.ip = ip;
        }
                
        public void run(){
           
          try {
                    socket = new Socket(ip, 8080);        //訪問指定的ip地址:8080
                } catch (UnknownHostException e) { 
                    e.printStackTrace();
                } catch (IOException e) { 
                    e.printStackTrace();
                }
                
         
           //獲取輸出流
            try {
                outputStream = socket.getOutputStream();
                
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }    
            try{
                while (true)         //讀取伺服器端發送來的數據
                {
                    final byte[] buffer = new byte[1024];//創建接收緩衝區
                    inputStream = socket.getInputStream();
                    final int len = inputStream.read(buffer);//數據讀出來，並且返回數據的長度
                    if(len>0)
                    {
                         Message msg = mHandler.obtainMessage(); 
                         //設置發送的內容
                         msg.obj = new String(buffer,0,len); 
                         mHandler.sendMessage(msg);  
                    }
                    
                }
            }
            catch (IOException e) {
                
            }
            
        }
        
        //向伺服器端寫入數據
        public boolean write(String text){
            
            boolean ret = true;
            try {
                outputStream.write(text.toString().getBytes());
            } catch (IOException e) { 
                ret = false;
                e.printStackTrace();
            }
            return ret;
        }
}