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这是我的工作代码。但是，当我尝试单击将客户端连接到端口的按钮时，我的应用程序崩溃了。看我的代码。

public class Order extends Activity {
    Button GoBackHome;
    private Button button1, button3;  
    private EditText txtbox1,txtbox2,txtbox3,txtbox4,textField;  
    private TextView tv;
    Button PayNow;
    CheckBox chxbx1, chxbx2, chxbx3,chxbx4;

    @Override
    public void onBackPressed() {
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
            setContentView(R.layout.order);

            GoBackHome = (Button) findViewById(R.id.gohomebutton);
            PayNow = (Button) findViewById(R.id.button2);
            txtbox1= (EditText) findViewById(R.id.editText1);  
            button1 = (Button) findViewById(R.id.button1);  
            tv = (TextView) findViewById(R.id.editText5);  
            txtbox2= (EditText) findViewById(R.id.editText2);
            txtbox3= (EditText) findViewById(R.id.editText3);
            txtbox4= (EditText) findViewById(R.id.editText4);
            chxbx1 = (CheckBox)findViewById(R.id.checkbox1);
            chxbx2 = (CheckBox)findViewById(R.id.checkbox2);
            chxbx3 = (CheckBox)findViewById(R.id.checkbox3);
            chxbx4 = (CheckBox)findViewById(R.id.checkbox4);
            button3 = (Button) findViewById(R.id.button3);
            textField = (EditText) findViewById(R.id.editText6);
            button1.setOnClickListener(new clicker());
            Button get_view_button = (Button) findViewById(R.id.viewsummary);
            get_view_button.setOnClickListener(get_view_button_listener);

            GoBackHome.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    final Intent i = new Intent(Order.this, MainActivity.class);               
                    startActivity(i);
                }
            });

            PayNow.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    final Intent i = new Intent(Order.this, Payment.class);               
                    startActivity(i);
                }
            });

            chxbx1.setOnCheckedChangeListener(new OnCheckedChangeListener() {
                @Override
                public void onCheckedChanged(CompoundButton buttonView,
                    boolean isChecked) {
                    if (chxbx1.isChecked()) {
                        txtbox1.setEnabled(true);
                        txtbox1.setFocusable(true);
                    } else {
                        txtbox1.setEnabled(false);
                        txtbox1.setFocusable(false);
                    }
                }
            });

            chxbx2.setOnCheckedChangeListener(new OnCheckedChangeListener() {
                @Override
                public void onCheckedChanged(CompoundButton buttonView,
                    boolean isChecked) {
                    if (chxbx2.isChecked()) {
                        txtbox2.setEnabled(true);
                        txtbox2.setFocusable(true);
                    } else {
                        txtbox2.setEnabled(false);
                        txtbox2.setFocusable(false);
                    }
                }
            });

            chxbx3.setOnCheckedChangeListener(new OnCheckedChangeListener() {
                @Override
                public void onCheckedChanged(CompoundButton buttonView,
                    boolean isChecked) {
                    if (chxbx3.isChecked()) {
                        txtbox3.setEnabled(true);
                        txtbox3.setFocusable(true);
                    } else {
                        txtbox3.setEnabled(false);
                        txtbox3.setFocusable(false);
                    }
                }
            });

            chxbx4.setOnCheckedChangeListener(new OnCheckedChangeListener() {
                @Override
                public void onCheckedChanged(CompoundButton buttonView,
                    boolean isChecked) {
                    if (chxbx4.isChecked()) {
                        txtbox4.setEnabled(true);
                        txtbox4.setFocusable(true);
                    } else {
                        txtbox4.setEnabled(false);
                        txtbox4.setFocusable(false);
                    }
                }
            });



    }

    private Button.OnClickListener get_view_button_listener = new Button.OnClickListener() {
        public void onClick(View v) {
          String r = "";
          if (chxbx1.isChecked()) {
            r = r + "\n" + chxbx1.getText() + ".............." + txtbox1.getText().toString();
            txtbox1.setEnabled(true);
            txtbox1.setFocusable(true);
          }
          if (chxbx2.isChecked()) {
            r = r + "\n" + chxbx2.getText() + ".............." + txtbox2.getText().toString();
            txtbox2.setEnabled(true);
            txtbox2.setFocusable(true);
          }
          if (chxbx3.isChecked()) {
            r = r + "\n" + chxbx3.getText() + ".............." + txtbox3.getText().toString();
            txtbox3.setEnabled(true);
            txtbox3.setFocusable(true);
          }
          if (chxbx4.isChecked()) {
            r = r + "\n" + chxbx4.getText() + ".............." + txtbox4.getText().toString();
            txtbox4.setEnabled(true);
            txtbox4.setFocusable(true);
          }
          textField.setText(r);

          button3.setOnClickListener(new View.OnClickListener()
          {

              public void onClick(View v)
              {
                  new ConnectToServerTask().execute(textField);
              }
          });

        }


      };



    class clicker implements Button.OnClickListener  
    {  
        public void onClick(View v)  
        {  
            String a,b,c,d;  
            Integer vis;  
            a = txtbox1.getText().toString();  
            b = txtbox2.getText().toString();
            c = txtbox3.getText().toString();
            d = txtbox4.getText().toString();
            vis = Integer.parseInt(a)*2+Integer.parseInt(b)*3+Integer.parseInt(c)*4+Integer.parseInt(d)*5;  
            tv.setText(vis.toString());  


        }  

    }  



}

我不知道下面代码的位置是否在其右侧。

button3.setOnClickListener(new View.OnClickListener()
          {

              public void onClick(View v)
              {
                  new ConnectToServerTask().execute

(textField);
              }
          });

这是我在服务器端的代码：

公共类 TestTCP { 私有静态最终 int PORT = 1485;

private static ServerSocket serverSocket;
private static Socket clientSocket;
private static InputStreamReader inputStreamReader;
private static BufferedReader bufferedReader;
private static String message;
private static String multiple;

public static void main(String[] args)
{
    try
    {
        serverSocket = new ServerSocket(PORT, 0, InetAddress.getLocalHost());

        System.out.println("IP:  " + serverSocket.getInetAddress() + "  Port:  " +  serverSocket.getLocalPort());

    } catch (IOException e)
    {
        System.out.println("Could not listen on port: 1447");
    }

    System.out.println("Server started. Listening to the port 1447");

    while (true)
    {
        try
        {{
            clientSocket = serverSocket.accept(); // accept the client connection
            inputStreamReader = new InputStreamReader(clientSocket.getInputStream());
            bufferedReader = new BufferedReader(inputStreamReader); // get the client message
            message = bufferedReader.readLine();

            while ((message = bufferedReader.readLine()) != null) {
                System.out.println("Message from Table 1: " + message);}
                inputStreamReader.close();
                clientSocket.close();}

        } catch (IOException ex)
        {
            ex.printStackTrace();
            System.out.println("Problem in message reading");
        }
        finally {
            try {
                if (bufferedReader != null)bufferedReader.close();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
    }
}}}

这是针对 Asynctask 的（如果您想查看它）：

public class ConnectToServerTask extends AsyncTask<View, Integer, Socket>
{
    private static final String IP_ADDRESS = "192.168.1.102";  // Kerv Server
    private static final int DEST_PORT = 1485; //port that is used

    private EditText mTextField;

    /**
     * Store provided views (used later in onPostExecute(...)).
     * 
     * Create socket to communicate with server (blocking call).
     */
    protected Socket doInBackground(View... params)
    {
        // Store provided views.
        if (params.length != 1)
            throw new IllegalArgumentException();

        mTextField = (EditText) params[0];


        // Create socket.
        Socket client = null;

        try
        {
            client = new Socket(IP_ADDRESS, DEST_PORT); // connect to server
        } catch (UnknownHostException e)
        {
            e.printStackTrace();
        } catch (IOException e)
        {
            e.printStackTrace();
        }

        return client;
    }

    /**
     * Write to server.
     */
    protected void onPostExecute(Socket client)
    {
        try
        {
            PrintWriter printwriter;
            String messsage;

            messsage = mTextField.getText().toString(); // get the text message on the text field
            mTextField.setText("\n"); // Reset the text field to blank

            printwriter = new PrintWriter(client.getOutputStream(), true);
            printwriter.write(messsage); // write the message to output stream

            printwriter.flush();
            printwriter.close();

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

日志猫：

08-29 07:36:54.398: E/AndroidRuntime(31968): FATAL EXCEPTION: main
08-29 07:36:54.398: E/AndroidRuntime(31968): java.lang.NullPointerException
08-29 07:36:54.398: E/AndroidRuntime(31968):    at com.example.controlsystemfinale.ConnectToServerTask.onPostExecute(ConnectToServerTask.java:72)
08-29 07:36:54.398: E/AndroidRuntime(31968):    at com.example.controlsystemfinale.ConnectToServerTask.onPostExecute(ConnectToServerTask.java:1)
08-29 07:36:54.398: E/AndroidRuntime(31968):    at android.os.AsyncTask.finish(AsyncTask.java:602)
08-29 07:36:54.398: E/AndroidRuntime(31968):    at android.os.AsyncTask.access$600(AsyncTask.java:156)
08-29 07:36:54.398: E/AndroidRuntime(31968):    at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:615)
08-29 07:36:54.398: E/AndroidRuntime(31968):    at android.os.Handler.dispatchMessage(Handler.java:99)
08-29 07:36:54.398: E/AndroidRuntime(31968):    at android.os.Looper.loop(Looper.java:154)
08-29 07:36:54.398: E/AndroidRuntime(31968):    at android.app.ActivityThread.main(ActivityThread.java:4945)
08-29 07:36:54.398: E/AndroidRuntime(31968):    at java.lang.reflect.Method.invokeNative(Native Method)
08-29 07:36:54.398: E/AndroidRuntime(31968):    at java.lang.reflect.Method.invoke(Method.java:511)
08-29 07:36:54.398: E/AndroidRuntime(31968):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
08-29 07:36:54.398: E/AndroidRuntime(31968):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
08-29 07:36:54.398: E/AndroidRuntime(31968):    at dalvik.system.NativeStart.main(Native Method)
4

1 回答 1

1

看起来问题出mTextField在. 您要么需要在该类中创建一个构造函数来接受您试图将其传递给您但它看起来错误的构造函数，要么将其设为内部类。如果你要通过它，那么它应该像nullConnectToServerTaskEditTextonClick()

new ConnectToServerTask(textField).execute;

然后有一个构造函数来取一个EditTextlike

public ConnectToServerTask(EditText textField)
{
    mTextField = textField;
}

这会给你带来更多的问题。但是，如果您使您AsyncTask的内部类成为您的内部类Activity并且textField是成员变量，那么您AsyncTask将已经可以访问它而无需传递任何东西。

编辑

public class Order extends Activity {
    Button GoBackHome;
    private Button button1, button3;  
    private EditText txtbox1,txtbox2,txtbox3,txtbox4,textField;  
    private TextView tv;
    Button PayNow;
    CheckBox chxbx1, chxbx2, chxbx3,chxbx4;


    // other functions such as onCreate()
    private class ConnectToServerTask extends AsyncTask<View, Integer, Socket> // inner class here inside your Activity
{
    private static final String IP_ADDRESS = "192.168.1.102";  // Kerv Server
    private static final int DEST_PORT = 1485; //port that is used

    private EditText mTextField;

    /**
    * Store provided views (used later in onPostExecute(...)).
    * 
    * Create socket to communicate with server (blocking call).
    */
    protected Socket doInBackground(View... params)
    {
于 2013-08-28T23:57:13.617 回答