java - TCP 套接字 Android 客户端

Question

我的 Android 套接字客户端有问题。我尝试将字符串从 android 客户端发送到 python 服务器。我在 netbeans 中创建了一个测试应用程序，代码可以工作，但在 android 上不起作用。我通过服务器上的字符串打印来验证数据是否到达服务器。

这是我的代码:

package com.example.tcp_button;

import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
import java.net.UnknownHostException;

import android.app.Activity;
import android.os.Bundle;
import android.widget.Button;
import android.view.View;
import android.view.View.OnClickListener;




public class MainActivity extends Activity {

    Button button;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.fragment_main);

        addListenerOnButton();

    }

    public void addListenerOnButton() {

        button = (Button) findViewById(R.id.button1);

        button.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View arg0) {

                DataOutputStream dataOutputStream = null;
                Socket socket = null;    

                try {
                    socket = new Socket("192.168.0.106", 5555);
                    dataOutputStream = new DataOutputStream(socket.getOutputStream());
                    dataOutputStream.writeUTF("on"); 
                } catch (UnknownHostException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

            }

        });

    }

}

这是日志:

03-27 20:38:49.388: E/AndroidRuntime(2367): FATAL EXCEPTION: main
03-27 20:38:49.388: E/AndroidRuntime(2367): android.os.NetworkOnMainThreadException
03-27 20:38:49.388: E/AndroidRuntime(2367):     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1128)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at libcore.io.IoBridge.connect(IoBridge.java:112)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at java.net.Socket.startupSocket(Socket.java:566)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at java.net.Socket.tryAllAddresses(Socket.java:127)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at java.net.Socket.<init>(Socket.java:177)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at java.net.Socket.<init>(Socket.java:149)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at com.example.tcp_button.MainActivity$1.onClick(MainActivity.java:46)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at android.view.View.performClick(View.java:4439)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at android.widget.Button.performClick(Button.java:142)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at android.view.View$PerformClick.run(View.java:18395)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at android.os.Handler.handleCallback(Handler.java:725)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at android.os.Handler.dispatchMessage(Handler.java:92)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at android.os.Looper.loop(Looper.java:176)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at android.app.ActivityThread.main(ActivityThread.java:5299)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at java.lang.reflect.Method.invokeNative(Native Method)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at java.lang.reflect.Method.invoke(Method.java:511)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
03-27 20:38:49.388: E/AndroidRuntime(2367):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

您应该尝试以这种方式制作Socket:

Socket socket = new Socket();
socket.connect(new InetSocketAddress(host, port), timeout);

// Use this just in case you have to read from the server
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream(), "UTF-8"));

// This will be used to send to the server
OutputStream out = socket.getOutputStream();
out.write("This is my message".getBytes("UTF-8"));

---- 编辑 ----

看到您的更新后，您的代码与此无关。你的问题是你把这段代码放在哪里，因为Android禁止在主UI中放置任何网络操作，因为它会阻塞与用户的界面，导致用户体验非常差，并且可能用户将卸载您的应用。

您必须将该代码放置在Thread 或AsyncTask 中。如果您开始使用它，您可能想尝试后者。这是 nice example .