EditText.getText Java.lang空指针异常

Question

I'm having a problem with my android program. I have about every thing working what i want, but now im trying to add a password dialog.

I want to show a Dialog with a EditText(enter password) and two buttons (ok, cancel). (working fine till so far)

When clicking on the OK button the password should be saved in mij SendData Class.

But every time I try to get the content of the EditText it gives a Java.lang NullPointerException.

Can some one help me please?

(I don't have a stack trace as i don't know where to find it :( because i'm testing on android emulator.)

If there any thing else you need, please feel free to ask.

Here is the XML-FILE

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <requestFocus />

    <EditText
        android:id="@+id/txt_wachtwoord"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:inputType="textPassword" >

        <requestFocus />
    </EditText>

    <Button
        android:id="@+id/DialogOK"
        android:layout_width="100dp"
        android:layout_height="wrap_content"
        android:layout_alignRight="@+id/txt_wachtwoord"
        android:layout_below="@+id/txt_wachtwoord"
        android:layout_marginTop="22dp"
        android:text="OK" />

    <Button
        android:id="@+id/Cancel"
        android:layout_width="100dp"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/DialogOK"
        android:layout_alignBottom="@+id/DialogOK"
        android:layout_toRightOf="@+id/DialogOK"
        android:text="Cancel" />

</RelativeLayout>

Here is the code:

    package SebApp.Phone.Remote;

    import java.net.DatagramSocket;

    import android.app.Activity;
    import android.app.Dialog;
    import android.os.Bundle;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;
    import android.widget.TextView;
    import android.widget.EditText;
    import android.widget.Toast;
    import android.os.Vibrator; 
    import android.app.AlertDialog;
    import android.content.DialogInterface;

    public class PhoneRemote extends Activity {

    private static final int VIBRATE_TIME = 100;

    /** Called when the activity is first created. */
    public Vibrator vibrator = null;
    public sendData sd = new sendData();

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

        vibrator = (Vibrator)getSystemService(VIBRATOR_SERVICE);      

        //button to call the Dialog
        Button ww = (Button) findViewById(R.id.ww);

        //listener password button
        ww.setOnClickListener(wwOnClickListener);

    }

    Button.OnClickListener wwOnClickListener = new Button.OnClickListener() {    

        public void onClick(View v) {           
            try{
                final EditText ww = (EditText) findViewById(R.id.txt_wachtwoord);
                //set up dialog
                Dialog dialog = new Dialog(PhoneRemote.this);
                dialog.setContentView(R.layout.wachtwoord);
                dialog.setTitle("This is my custom dialog box");
                dialog.setCancelable(true);
                //there are a lot of settings, for dialog, cheout!

                //set up button
                Button button = (Button) dialog.findViewById(R.id.DialogOK);
                button.setOnClickListener(new OnClickListener() {
                    public void onClick(View v) {                 
                        try{
                            Toast.makeText(v.getContext(),"PWfield contains: " + ww.getText().toString(), Toast.LENGTH_SHORT).show();
                            //finish();
                        }catch(Exception e)
                        {
                            Toast.makeText(v.getContext(),e.toString(), Toast.LENGTH_SHORT).show();
                        }
                    }
                });           
                dialog.show();
            }catch(Exception E){
                Toast.makeText(v.getContext(),E.toString(), Toast.LENGTH_SHORT).show();
            }

        }
    };
}

Answer 1

 Button.OnClickListener wwOnClickListener = new Button.OnClickListener() {    

        public void onClick(View v) {           
            try{
                final EditText ww = (EditText) findViewById(R.id.txt_wachtwoord);
                //set up dialog
                Dialog dialog = new Dialog(PhoneRemote.this);
                dialog.setContentView(R.layout.wachtwoord);
                dialog.setTitle("This is my custom dialog box");
                dialog.setCancelable(true);
....

instead use

Button.OnClickListener wwOnClickListener = new Button.OnClickListener() {    

        public void onClick(View v) {           
            try{

                Dialog dialog = new Dialog(PhoneRemote.this);
                dialog.setContentView(R.layout.wachtwoord);
                final EditText ww = (EditText) dialog.findViewById(R.id.txt_wachtwoord);
                //set up dialog
                dialog.setTitle("This is my custom dialog box");
                dialog.setCancelable(true);
....

you had declared EditText before setting the dialog view

Answer 2

I have yet to run your code. However, I would say the variable wwOnClickListener is being initialized before the onCreate method.

Therefore the layout is not set, as the layout is set within the onCreate method. To fix this I would pull out the following

final EditText ww = (EditText) findViewById(R.id.txt_wachtwoord);

From the buttonlistener and make ww a global variable which is initialized in the onCreate method.

I would expect that will resolve the issue.