在java服务器中发送edittext时出错。 看代码

这是我的工作代码。 但是，当我尝试单击将我的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定位是否在其右侧部分。

 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 {private static final 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（如果你想看到它）：

 public class ConnectToServerTask extends AsyncTask { 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(); } } } 

logcat的：

 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) 

Answer 1

看起来问题是在ConnectToServerTask中mTextField为null 。 您需要在该类中创建一个构造函数来接受您尝试在onClick()传递它的EditText ，但它看起来不对或使其成为内部类。 如果你打算通过它，那应该是这样的

 new ConnectToServerTask(textField).execute; 

然后有一个构造函数来获取EditText

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

这会给你带来更多问题。 但是如果你使AsyncTask成为Activity的内部类而textField是一个成员变量，那么你的AsyncTask就可以访问它而不传递任何东西。

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 // 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) {