Android套接字编程

Question

我正在尝试制作一个简单的 Android 应用程序，通过 WiFi 将字符串发送到微控制器，该微控制器稍后将用作打开和关闭 LED 的命令。

以下是我拥有的代码，我在理解它为什么不起作用时遇到了问题。 基本上抛出异常并引发“连接失败”吐司。

     String hostname = "192.168.50.1";
     int port = 5001;
     PrintWriter out = null;

     //access_point.connect(new InetSocketAddress(hostname, port));

    public void command() throws Exception {

        try{
             Socket access_point = new Socket(hostname,port);
            out = new PrintWriter(access_point.getOutputStream(), true);
            out.println("Turn on"); 
            Toast.makeText(getBaseContext(), "Connection successful", Toast.LENGTH_LONG).show();
        //  BufferedReader in = new BufferedReader(new InputStreamReader(access_point.getInputStream()));
        }
        catch(Exception e){

            Toast.makeText(getBaseContext(), "Connection failed", Toast.LENGTH_LONG).show();

        }



    }


     ToggleButton tbutton;

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

        setContentView(R.layout.activity_fullscreen);

        // code for toggle button 
        tbutton = (ToggleButton) findViewById(R.id.toggleButton1);
        tbutton.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                if(((ToggleButton)v).isChecked())
                {
                    try{
                        command();
                        Toast.makeText(getBaseContext(), "Communication ON string sent", Toast.LENGTH_SHORT).show();
                    }

                    catch(Exception e)
                    {
                        Toast.makeText(getBaseContext(), "Communication failed", Toast.LENGTH_LONG).show();
                    }


                }
                else
                {
                    Toast.makeText(getBaseContext(), "Communication OFF string sent", Toast.LENGTH_LONG).show();
                }       
              } 
            });
        }
}

Answer 1

你应该使用

    Log.d(getClass().getSimpleName(), "Connection failed", exception);

您可能遇到的问题是您在主线程上运行网络连接，这可能会在超时时冻结应用程序，因此 Android 操作系统不允许这样做。

查看此问题以获取有关如何在不同线程上运行网络连接并解决您的问题的更多信息：Using AsyncTask for android network connection