Disable button till validation

*********Java file**********

import android.app.Activity;

import android.widget.EditText;

import android.widget.TextView;

import android.widget.Toast;

import android.os.Bundle;

import android.text.Editable;

import android.text.TextWatcher;

import android.view.View;

import android.widget.Button;

import android.text.method.*;

import android.view.View.OnFocusChangeListener;

import android.view.View.OnClickListener;

public class ThirdActivity extends Activity {

    /** Called when the activity is first created. */

String uname="ronak";

String pwd="password";

boolean idstatus=false;

boolean pwdstatus=false;

Toast myToast;

static int toast_count=0;

@Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.login);

        

        final Button lbutton=(Button)findViewById(R.id.button1);

        final EditText etUsername=(EditText)findViewById(R.id.editText1);

final EditText etPwd=(EditText)findViewById(R.id.editText2);

        etUsername.addTextChangedListener(new TextWatcher() {

@Override

public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {

// TODO Auto-generated method stub

String data=arg0.toString();

if(isEmail(data))

{

/* if(myToast!=null)

{

myToast.cancel();

}*/

if(toast_count==0)

{

myToast=Toast.makeText(ThirdActivity.this, "Email or Username is correct", Toast.LENGTH_LONG);

myToast.show();

}

toast_count=1;

if(uname.equals(etUsername.getText().toString()))

{

idstatus=true;

}

else

{

idstatus=false;

}

}

else

{

idstatus=false;

toast_count=0;

}

}

@Override

public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,

int arg3) {

// TODO Auto-generated method stub

}

@Override

public void afterTextChanged(Editable arg0) {

// TODO Auto-generated method stub

if(idstatus && pwdstatus)

{

lbutton.setText("Login me");

lbutton.setEnabled(true);

}

else

{

lbutton.setText(null);

lbutton.setEnabled(false);

}

}

});

        etPwd.addTextChangedListener(new TextWatcher() {

@Override

public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {

// TODO Auto-generated method stub

if(pwd.equals(etPwd.getText().toString()))

{

pwdstatus=true;

}

else

{

pwdstatus=false;

}

}

@Override

public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,

int arg3) {

// TODO Auto-generated method stub

}

@Override

public void afterTextChanged(Editable arg0) {

// TODO Auto-generated method stub

if(idstatus && pwdstatus)

{

lbutton.setText("Login me");

lbutton.setEnabled(true);

}

else

{

lbutton.setText(null);

lbutton.setEnabled(false);

}

}

});

    }

    protected boolean isEmail(String etUsername)

    {

int i=1;

int len=etUsername.length();

while((i<len) && (etUsername.charAt(i)!='@'))

{

i++;

}

if((i>=len) || (etUsername.charAt(i)!='@'))

{

return false;

}

else

{

i+=2;

}

while((i<len) && (etUsername.charAt(i)!='.'))

{

i++;

}

if((i>=len-1) || (etUsername.charAt(i)!='.'))

{

return false;

}

else

{

return true;

}

    }    

    

}

************XML File**************

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

 android:layout_height="fill_parent" android:layout_width="fill_parent" 

 android:orientation="vertical"  

 android:gravity="center" android:background="@drawable/desktop_3">

  <LinearLayout android:layout_height="272px" android:layout_width="305px" android:orientation="vertical" android:gravity="center" android:background="@drawable/desktop_7">

 <TableLayout  

  android:layout_width="wrap_content" android:background="@color/Bgcolor"

  android:layout_height="wrap_content" android:gravity="center" android:padding="10px">

 <TableRow>

 <TextView android:text="@string/LoginTitle" android:id="@+id/textView1" 

android:layout_width="wrap_content" android:layout_height="wrap_content"

 android:textColor="@color/Fgcolor" android:padding="10px" android:textSize="25px">

 </TextView>

 </TableRow>

 </TableLayout>

 <ScrollView android:layout_height="wrap_content" android:layout_width="wrap_content">

<TableLayout  

  android:layout_width="wrap_content" android:background="@color/Bgcolor"

  android:layout_height="wrap_content" android:gravity="center" android:padding="10px">

<TableRow

  android:gravity="center"

  android:orientation="vertical" >

  <TextView android:text="Username: " android:id="@+id/textView1" android:layout_width="wrap_content" android:layout_height="wrap_content"

    android:gravity="center_vertical"

    android:textColor="@color/Fgcolor">

    </TextView>

      <EditText android:layout_height="wrap_content" android:id="@+id/editText1" android:layout_weight="1" android:layout_width="wrap_content"

    android:gravity="center_vertical" android:hint="Username">

        <requestFocus></requestFocus>

    </EditText>

  </TableRow>

  <TableRow

  android:gravity="center"

  android:orientation="vertical">

     <TextView android:text="Password:" android:id="@+id/textView1" android:layout_width="wrap_content" android:layout_height="wrap_content"

    android:gravity="center_vertical"

    android:textColor="@color/Fgcolor">

    </TextView>

    <EditText android:layout_height="wrap_content" android:id="@+id/editText2" android:layout_weight="1" android:layout_width="wrap_content" android:inputType="textPassword"

    android:gravity="center_vertical" android:hint="Password"></EditText>

  </TableRow>

 <Button android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content"

  android:typeface="sans" android:hint="Enables only when all fields are correct"

  android:textColor="@color/Bgcolor1" android:textStyle="italic"

  android:enabled="false" android:layout_marginTop="15px"></Button>

  </TableLayout>

  </ScrollView>

  </LinearLayout>

</LinearLayout>